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CROCODILES
Proceedingsof the 14th Working Meetingof the CrocodileSpecialist
Group
of the SpeciesSurvival Commissionof IUCN - The World Conservation
Union
convenedat
Singapore,13 - 17 July 1998
(UneditedandUnreviewed)
tiR${t0l}ll,lt
IUCN - The World ConservationUnion
RueMauvemey28, CH-I196,Gland,Switzerland
1998
Coven Chineseallig or Alligator sihensisA criically endangeredspeciesand lop CSG priority for
@nserration. Cunenl captjve breding and habibl prolecllon effons under*?y in Chitu rvill be crucal
for this speciessurvi\al (seeWan ZFmng, Gu Chang-min& WangXiao-ming & Wang Chao-lin Pages
80 -1001. R GodshalkDhoto
Litemturecitationsshouldrcadasfollows:
Forindividualanicles:
Crocodiles.Proce€dings
ofrhe l4rh Working
I4udro4. -1998 lAnicle tirlel. pp lnunbersl 1,:
Medng oftheCrocodile
Spe.ialisl
Group,ruCN- TheWorldConservadon
Union,CtandSwiderland
and (lmbndse
uK
For the rolume:
CrocodileSpecialig Croup. 1998 Crocodiles. Proceedingsof the l4rh Workine Meetins offie
Crocodile SpecialistCrou-p.ruCN - T}|e World Conservad;trUnjon" Cland. Swi-klrland;nd Canbridge.
uK: x+ 4ft PD.
O Copfight 1998ruCN - The World ConservationUnion
The designalionof geographicalendties in this book, ard tl€ presentationofthe material, alonot iflply
the e&ression ofany opinion *hatsoeveron lle part of ruCN concemingthe legal statusofaiy co!ffry,
territory, or 6re4 or ofils authorities,or concemingtlle delimitation ofitJ frodiers or bounclaries.The
opini!_nsex?ress€din this volume are thos€ofthe aulhorsa d do not necessadlyrcpresentofrcial policy
of ruCN or CSG or its members.
Reproductionofthis publication for educalionaland other non{onmercial purposesis aufnrized
$rithoutpenDssronfiom rhe copFight holder.piovided the sourceis cited and ihe copyriglt holder
rccflves copy or urereproduceomaterrsl.
Reproductionfor resaleor other conmercial purposesis prchibited {ithout prior rrTittenpemission of
tne copyflgnr noner,
ISBN: 2-8317{457-7
Published
by: ruCN/SSCCrocodileSpecialistGrcup.
Table of Contents
Summary
oftheMeetiry.
............................................v
Acloowledgements.,,...,.,
Conservation of crocodilians in S.E. Aria
Stuebing,R B, Engkanat Lading & JohnsonJong. The statusofdre FalseGhaiat (Tatuistoma
rcrleg€lttMueller)in Sara&"k
......................1- 9
B€zuijeD,M. R, G. I W. Webb,P. Itunoyo, Samedi,W- S. irmono & S. C. Mamlis. The False
Ghaial (Tonistomaschlegelit)in Sumatia.
.......................................
10 -31
Simpso4 B. K., A. Lopez, Sharunbin abdLatif& Alias bin mat Yusoh. Tomis.omz(Tomistoma
- 45
rcrlegelt)at TasekBer4 Peninsular
Malaj'sra.................
..................32
Ross,C. A., J. H. Cox, H. Kmdati & S. Frazier. Pr€liminary sun€ys ofPalustrine crocodilesin
- 79
Ks1irnaflr.n....................
.............................46
Wan Zi-min& Gu Chang-ming Walg Xiao-ming & Wang Chao-lin. Consemtion, managem€nt
- 100
in China....-..........-.........
andfarmingof crocodiles
........................80
- f34
frega G. v. PhilippineCrocodileconser%tion,
Comprehensive
report.......-.............................l0l
Cao Van Sung& R
.w'
G. Jenlcins.CrocodileConsenationand developmentin Vietnam. -.-.-...135 - 140
in captivityandin the*ild-.......................
NaoThuok. Currentstatusofoocodilein Cambodia
141- 154
Impects of contamina[ts oB crocodilian populrtions.
Brisbio, I. L., C. H. Jagoe,K. F. Gaines& J-C. Gariboldi. EnviromnentatCo aminantsas concefirs
- 173
for the consenationbiolog/ ofcrocodiliam......-.....
........................155
Crews,D. & J. P. Ross. Consequences
of homone disruption oi sexualdevelopmentfor crocodrlian
- 190
conseirvation.
...._................_...................174
Rice,K. G., H. F. Percil€l;, A. R Woodward& C. L. Abercronbie. Populationd)1l?micsoflake
Apopka'salligators.
.......
l9r - 205
........................
RainEater,T. R, S. Platt & S. T. McMurry. + A population studyofMorele!'s crocodile
- 220
(Crocodylus
noreletii)]n theNew RiverEatershed
of NorthemBelize...........
......................206
SwanAoel,t. G. I Nile crocodile(C/rcoaylr.r rilofrcl/s) researchprojectin the Kruger National
-229
ParlqSouthAfrica....-....
........................221
*
Indicalespapersnot presentedat the me€tiry.
World Trade in crocodilianski . Current eventsandtrctrds.
RosrJ.P. TradeWorkhop
- 232
................._........230
KoL C.H. Asiareport..Takehara,
Y. CrocodileskinmarketinJapan..............................-..
-240
.................233
.-....241-242
- 253
Ross,
J.P. Repo(onqocodilian
traale
fromLaiinAmerica.
.............-.-.-..-.-...........
.....................243
- 263
Asbley,D. Intemational
alligator
ard qocodileuadestudy.
........-.........-......
............-..--..-.-..-.-...254
Sin[es4V CrocodileIduslry PloductionData NorthemTerritoryAustralia1994-1997.
.........264- 267
Evrlualiotr of re-introductio of crocodilia.ns
as a cons€rvation
tool.
-Price.General
- 284
Soorae,
P. S.& M. R Stantey
i{roduction!o rc-introductions.
..........................268
Soo.ae,
P. S.,J. Elliott & P.Muruthi. Relativecostsofre-introducingcrocodiles
to thewild.......285-291
Elsery,
R M., L. McNease,
E. B. Moser& R. G-Frcderick.Re-introduction
ofalligatorsandother
crocodrlians...................
.........................................292
ChabrechR H., v. L. Wright& B. G. AddisonJr. Survir€lindic€sfo. faim-released
American
- 304
alligators
in a freshwater
nursh.........................-..
........................293
Addiso4B. G.,R H. Chab.eck& V. L. Wriglrt. Movenentofjw€lile faim-released
andwild
Americaialligatorc
in a freshwater
marshin Louisiana
.................
305- 3l0
Ferguso4
R Re-introduclion
of Nilecrocodiles
to L.ake
Kariba,Zimbabwe.
..............................._.
3l l-312
Munoz,M. del C. & J. B. Thorbjamarson.
Radio-tracking
captiv€rearedOrinocooocodiles
(Ctocodylusintermedius)relersedintotheCapanaparoRiver,Venezuela............................3l3-31
progmmfor Americancrocodiles
Velasco,A. & A. tander. Evaluadonoftlrc reintroduction
(Crocodylus
- 324
aattus)in theCu.are
WildlifeRefugqlalcon State,Venezuela.
........................320
Physiologrof r€pmductiodin captivity,
Lanc€,v. A. & R. M- Elsey.Physiology
of.eproductionandcaptivebreedingin lhe American
alligator.........................
................................325
L{ayer,R, S-Peucker,B. Davis& H. Stephenson.
Envirorunental
conditionsfor regJingCracodylus
polosll'onfarnrs........._.
...........................326-332
Davig8., R J. Mayer& S.K. PeuckerRese€rching
therequircments
ofcaptiveestuarine
- 344
crocodiles
in Australia.
..........................333
Huchzedray€r,
F. W. * Apparentimprintingof crocodilebarchlingsandpossibleimplications.. 345- 346
Iaon Ojeda,F.J.,P.L. AredondoRamos& MC. RoblesMontijo.* Artilicial incubationofeggsof
- 352
Crccodylus
norcletiii^ captivity.
.....-..........-.-...........
....................347
I-€on Ojed4 F.J., P. L. ArredondoR2mos& M.C. RoblesMontijo.* Use of anabolicsteroidsin the
-359
..................353
commercialiaisingofqocodiles..-..-...-.......-......-.-.-.....Methods and t€chniques.
Britto4 A. R C., B. Otley & G. Webb. A report ordle helicopter surveysofC/ocodylus poroslls in
360- 364
........................
theNorthemTerritoryofAustralia........................
Miller, J. D., M. Read& P. Koloi. Application ofceographic Infoimation System(GIS) technolog/
365- 370
in Quee$land,Australia...........................................
to crocoalleresearch
andmanagement
Slleddor! H., P. G. Hepp. & C. Manolis. A pre-hatchmethodfor influencing the diet eatenafter
.............37| - 317
balching in the saltwatercrocodiile (Crccodllus poroslts).
MiscellaneousDapers
adtus i\ ihe Ta.rcoles
River,CostaRica............................378
Abadi4 G. &M. F. Oduela.* Crocodylus
lrrriei4 A. 'f me Caimanlatirostris nnching programin Sada Fe, Atgentina: the first
- 385
........................3?9
cofimercialrearing1998
Rao, R J .. Conservationstatusof crocodilesin India: a compamtivearal)sis in protectedanc
...... .......386_401
u n D r o t e crt ievde r s . . - . - , . , . .
whitaker,N &H. Andreffi. * IGdns CrocBar*: ar update.....................-.-..........
Stacey,B. + The trouble with high density:
BarkTrust.
Veterinary
aqpects
oitheMadrasCrocodile
402- 406
- 410
..............407
Indicatespapersrct presented
at themeetrng.
CROCODILE SPECIALIST GROI]P
The Crocodile Specialist Group (CSG) is a worldwide rctwo* of biologists, wildlife managerc,
govemmentofrcials, independentrcsearchers,non-governmentalorganization reptsentatives, farmers,
traders, tanne6, manufacturers and private compames actively iNolved in the consenadon of
crocodilians (Crocodiles,Alligaton, Caimansand Gharials). The Group opemtesunder the aus?icesof
the Species Survial Conmission of ruCN. The CSG provides a network of experts to assess
@nseri,:rtion priorities, devel@ plans for research and consenation, conduct suveys, estinate
populations,Fovide lechrical information ard trainin& and to abaft conselration prograns and policy.
CSG also assi$s monitoring intemational tnde ard identifying products. The CSG work closelyrYitl
CITES to promote srstainableus€ aIId intematronaltrade that benefits rc conservationof cocodilians.
The Group is headedby ils chairmaq ProfessorHarry Messel, and maintains ofiices in Gainesville,FL
USA. Working Meetingsofthe CSG are held everytwo )€ars.
iv
FOR.EWORD
Onceagair CSGmembers
havecoN€nedftom aroundthewoddto adalress
cllrrenlugent consen?tion
issuesofdocoalilia$. This meetinglr€s deliberately
locatedin S.E.Asiato highlightthe high dir€rsity
of crocodiliais and the severethreatsfacing them ilr this rcgion. Rapid economicdevelopment,
includidgan inGnseinterestitr crocodilefarmingand trade,providesus with drc opponunityto ensure
that use of crocodiliansin tlie regionis $rstainableand providesconsemtionbenefitsto the wild
populations
andthei.llabitats. At this meetingFe haveseenthebenefitsderivedfrom higblightingone
sp€/cies,
Tomistoma
schelegelri,which has re$rltedin ftnding ard an intens€srrvey efort. We a&
coDfidentlhat we calrnow changethe consenationassessment
of this speciesfrom DataDeficientto
Endar€erEd.This is the Ir€y the CSG$orks, identifythe pmblen, conductthe research,prcvidetlrc
information10direct plicy and consemtionaction. We expressour geai thank to out frienalsin
Singapore
andthroughout
the regionfor providingthevenueandpladord ard thevital supFononwhich
ouf efortsrely.
Prolessor
HarryMess€I,ChainnalCSG.
SUMMARY OF TEE MEEIING
About 140 CSG membersconvenedin Singaporcbetween14 and l7 July 1998for our biennial
\rorldwidemeetiDg.Thefacilitiesandarmngements
of&e meetinghosts,Singapore
ReptileSkinTrade
Association,
wercimpeccable
andpanicipantswerequicklymadeto feel comfortable
amongSingapore
slgscrapers. Th€ meetirg w€s openedby Dr. Ngiam Tong Tal! Director, prinary production
Depafirnent,Mnishy of NationalDevelopmmlafter welcomingcomments
by Mr. Koh ChoonHeong
representing
thehosls,Singapore
ReptileSkinTradeAssociation,
andProfessor
Messel.Chairnllt ofthe
csG.
The wo*ing pan ofthe meetingbeganwith a seriesof Fesentationson rccentwork on forrjrtoma in
Sarawah Sumata and Kalinaitan, follo!'ed by vigorons discussionby Frticipants. In lhe aftemooq
colleaguesiiom China presentedresults and idonnation on the rapidly developingsituation lhere and
Gerry Ortegaofthe CrocodileFarming Institute gavea comprehensivedescriptior of lie many admnces
rnadewitl th€ captivepopulation ofthe Philippine crocodile.
The meeting corfiflted i high gerr with a sessiondetailing the newly recognizedproblern of s:ub.
lethal le\€ls ofpollution affecting rcproductivehormonesin alligators. The recent similar phenomena
observedin l-ak6 Griffn, Florid4 wele describedand in discussionthe possibility that such efiectsmight
be widespreadi! both wild ard captivesituations*?s presented.That aiemoon a seriesofpresentations
on world trade detailedthe c1rrrentdeFessedstateof the crocodileskin na*et and led to a discussiol of
lrorc acti\€ meas.rlesCSGmight take to promotethe consenation\due ofcrocodilian use_
The combination of indepth papers and er.lensive discussion continued the following day widr
sessionsewluating reinttoduction as a consemtion tool aIId more presentationson tle sitoation of SE
Asian crocodiles. Quite striking contmsts b€tween results of {€introductiotrs obtained in difierent
situalionsand by ditrercnt workerswere rcpoded. Thereforeeachparticular situation shouldbe analyzed
rigorcusly. An introduction to generalpdnciples of rcinUoduclion progams bryPdtpal Sooraeof the
IUCN Reintpduclion SpecialislCroup provided a r"luable fi'amework{or discrssion. New information
ftom Cambodia and Vietnam ard an upalate on the situation in Thailand fiflher brcadened our
rmalerstandiqgof the need for conservationaction in the r€gion to hamessthe energy of al:veloping
comrnercialintercststo ensureconsemtion ofwild croco&lians.
In a special sessiorlpanicipads used the ruCN crileria to re-ajsesslhe statusof SE Asian species.
Nel/' infornation ar€ilable on Tomistomaas a rcs!7t of the aclivities promotedby declaring this species
our 6rst pliority in 1992wEreeBluated and the meetingconcludedthat the conec1s1^t\sfor Tomistoma
was Endangered. The orrent e\,aluationsof crocodiliansin the Asian xq were confrnae/l. Alligator
sinenis, Crccodybs siatnensisand.C. minilorensis rcmain Criticatly Endangered.and C. polosus, C.
johfisoni and C. noweguirede remain l,ow Risk of Extinction. Howevet it was noted that c. polo.rrs
may be Endangeredin many pans of jts range,but is securein Austr:alia,PNG and Indonesia. This led
to a detaileddiscussionof rhe applicability of ahecdteria to longlived specieslike crocodilia$s.
On the final day oftlE meetingVal Lancechaireda sessionon physiologic€lbasrsof reproductionin
captivit and gave a comprehensivereview of2o-years res€arch. Additiona.l contibudons on the recent
mycoplasm dise€seoutbre.akin St. Augustine Alligator Farm and ressrch on captive husbandry in
Queenslardlounded out this useful practical sessionard again promptederlensive discussioo, Afrer a
brief closureand er?ressionofthanks to the orgranizen,participar[s went on field trips to the Heng Long
lannery and Lng Koan Hung Crccldile Farm whereagain they receivedthe generoushospitality of our
Sin9pore hosts.
Paperspublishedin this volum€ include thosepresentedat the meeting,exlendedabstiacb of seveml
postersdisllayed at th€ meetingard a numberof reler€nt papersslbmitted by authorswho were uiable
to attend. As custonurt for CSG Proceedingsthes€are prcsentedas they werc submittedby the authors
without review or corection aad serveas a rcadv soulce of ournt and new information on docodrlia!
rcs€archmanagementard consenadon.
PerranRoss.Exe&d!€ Offrcer CSG. Ma$ging Editor l4d ftoceedngs.
ACKNOWLEDGMENTS
The Crocodile SpecialisrGrcup would like to tharik the Singpore Reptile Skin TraaleAssocratior for
hodting tle l4th Working Meeting ard the Organizing Conmittee for plafiing and coordinating the
four{ay event in Singapore- The oqanizers *ould like to acknowledgethe following companresard
organizationsfrom Singaporefor their sponsoNhipofthe meeting:
(s$3o,ooo)
Sponsors
Hery Lolg l,eather Co (Re) Ltd
(s$3,ooo)
TanMohHongReptile& Crccldile
ReprileSkinTiadeAssocratioir
Singaporc
- s$2,000)
(s$r,soo
Abadi Jala fte Ltd
ChekHong LeatherCo
Long Kran Hung Pte Ltd
Nam Heng L€athe! Dr€ilg
(s$1,000)
B S Anmugsm
HoongCheoq
K*anFn Reptilehoducts
(below5$1,000)
AC Galstaun& Co.
ChanYewLeatherBagsMlr
ChyeSengTanaeryPteLtd
FarEaslReptileHouse
FerraganTradingCompany
GenghizKur Enterprise
Krm Thong
LeeChingLeatherCoodsMfi
I-eong'sLeatherProducts
Mfr
Lim's ReptileGoodsMft Co
Lift Pui YongReptileGoods
NagoyaReptileCofte Ltd
Nar Kai CrocodileSkinGoods
TanHengTanneryfte L1d
WahCheongI-ealher
Singapore,
Specialthanksaredueto Mr. GeraldOng,Ms. WedadSunnyofForewodCrmmunications,
andtheir slafrfor excellentmeetinganangements
andassistalce
to delegates.
Travelsrpportard
assisrarce
for panicula.rdelegale's
travelwasproudedby thefollowinginsritutionsandindrviduals:
FarmaIIdZoo;
SingapoleReptileSkinTradersAssociation;
N{r.UthenYoungprapakor&
Samuorakan
MelboumeZooiJackCox;Wildlife Instituteof India;Mr. Vem Weitzel,
Wildlife Consen€tionSociery;
Australia-ViehamScience
Technology
Link; EmirateAirwats;EcologyAustmliaPty.Ltd..
Participants
at the 14' WorkingMeetingofthe CSG
TheNanrc@cy
P.O.Box 630162Ch6a Zrhbir
chlone, Nc 282rr-2635 UsA
El Shddai 14200sw s4 sir€t
Tibe I, 2942r Bald
In LBia
Dcpdtraent otz@log/ ad Pctrlol.
Itr51iture
of Dcoloe/ ed Biolosicd
lod Big #4 M,rDllo'tu
603104Tmil Nadu tldi.
wel Topi6 Mmgdar
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stateUniv6ity
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Bals R@ep70803 Idlsi@ usA
Audnrid cro.odile Tndrs
QLD4870 Caitu Auslralia
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Que@ AveN DiliM Q c 1100
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Banekok10120 Th.ildd
Wildlife MegdBr
InGnaliml
Min, Smxik
Sxrdtu
Mala)3ia
NT 0312 Arslrali.
westh Als1Flia 6276 A!*.alia
Ta Moh lldg RertiL Skin &
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W6rqn A&{ali! 6276 AIdnli.
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5476 Cr&d ClEir g*t
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PO Box r 8, Ctodrabdi,
Ctrodik fffi
Assialion of
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lliglJo& Hare Zimhabw
Wildlife M@e;Et
Sar{kMNTO8L
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Bund€sdr tur NanFhuE
KvdF
Reptiletroducls
Bll 5071 Ang Mo Ki. Ar 5
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Cabor4 ACT 2601 AIsL.lia
Blk 5071 Ang Mo Kio Ar 5
Arg Mo Kio Induslial ParL2 tr02-
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H.dds
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15CNnd n@, wis
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Kel!.n CepB Chatuchnli,
Bo8ldq 10900 Th.ilard
st b.4
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Fldid! MwM
ofN.rional gi{ory
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Kua 1168 CraodiL rld
GainNiI€ nqid. 32611-7800USA
I 1350sro.*ltolin swcd4
V.rai!.ry RMch
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Hflg lag t!*htr
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gens l,ng lathd
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Derardlq'l
ed Thining
t ng (e
Hmg CraodiL lm
OrddlI.?@!t veldin ty lr$iate
01l0 Oldqd.pdt
SoulhAAie
Chmbui CeodiL &d Rsi
ttl
lrinuiy rrod!.lid
Dcpartnat
Uai!6ity of stellobcchE
ex.l
ENnqnHrr/CMdd
N.1t@.1Cr@dile Mditdins Unjr
Hengrrg
rsdd
Co. (Pt ) LLl
PqtMoc6y
Cr@dile F.ffi
Asiatio
?.O.BoxIlCrl
of
!.pu! Ns Guin€
Ldosie Indtnrle ofs.iei$
Widyet*slo&. Building
J.k rla-Bogd cibinds 1691l,
viii
Bi.Ea
Produclid D.p{tberlr
Sin8!9cE Zelogi.ai
Pdhory Prod!.tid
2F M.it! Bld& 2-4-9 Keituinon
Ttitcku Tokyo 1114034 J5p@
D
CantqE
DcpoltDot
Cr@odileFmjrs
tO Box l0l
P.l.w
Islhrr.
Sonn CNlina 29J98 USA
3500 PhilippiB
Te Mon Hog Re/il. skin &
790 Uppd Stugm
R@d
N..k i Creodile Skin Go.ds
Radduluqi701l0 TlBiland
p03.12t13
Takasnimy. S. C, NCe ArD Cily
Japd Larhd o.l t aihd Gbo&
WiLlif. Meganerf lnrdnalioral
Sanlcrsor,
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T.ncku Tokyo 1114034 Japd
Scb@lofstudia in Z@los/
AIBASRercl' & llnialic
Oldmw-kn 90+002 J.p.r
D€d .trPrinEry
Qu$Ijd
Sinllpor. Z6l%i6l
O{da$
Croodil€ M&Egdh Asiario
of
Dcpt oiz@Iory. laalty ofsci@
AanCkl& 10900B.ngkok TlaiLd
D,p. of Primrt Inrnrdty & rilndic
GPOBd99O
PO Box 105
QueELnd Itp.rt:rdl
Ql|€6lddrl8l0
of
AEialia
tO. Box J39r
nd{et*
C.ic
CE k Crcedil. F@
QLD 44,
Q@land
4810
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Cn@hli 20110 Thailard
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Thail,ld
The Statusof the FalseGharial
(TomistomoschlegeliMueIIer) in Sarawak
RobertB. Stuebing
ITTO Unit
SarawakForestDeparbnent
lluchin& Sarawak
EngkamatLading
NationalPar}s and Wildlife Office
SarawakForestDepartment
Kuching, Sarawak
JohnsonJong
Jong'sCrocodileFarm
P.O Box 670
Kuching Sarawak
INTRODUCTION
Though lnown for over a c.ecuy as rruseurnspecimens,the ftlse gbariat Tornistorrra
xhlegeb, Ms rcnnirrad,somewhalof a nrysteryin tems of its dishibutiooard abundanc€.
A
ctypticallycolouredand secretiveAecies,the inacc€ssibility
of its swampyhabita nukes it
dificult to d€tect,while its non-aggressiedispositiondoesnot betrayits preseuce
by conflict
with busuls. Therebavebeenno cn€ys in SamrEk dsrcted exclusiletyto the species,
althoughCox & Gombek(1985)ircludedit it their gercralsurveyofcrocodiles. Therehave
beenfew field zurve1ssinc4 parttyb€causetav€rsingT. schlegeliha}idixbboth difficult and
time coooming. Lack ofid€rest cor d alsobe causedby the specieshavingno localorltural
irlportflrce nor any significaft economictalue (the skin is not traded loc€ty). Tlnls the
distributionand strtus of T. scuegeli in Sua] ak i! yet to be propedydocutrrflte4 and the
specieshas receivedlitde attentiondespiteits listing among Sanwak's protectedwildlife
(Anoq 1990).
DISTRIBUTION
the historicaldistributionfor the fals€ gharialuas frorr southeastem
Chir4 Thailandand
Bunn4 PeoinsularMalals4 Surnata and Bomeo. Its qJlreot distibution in Malaysia-
Indodesiaincfudesa srnallportiooofPednerlar Malaysia(TasekBera), east€f,n
and southem
Suuntr4 and the islandof Bomeo (Sebastia41993). De Rooij (1915)IistedSadongaad
Muka in SarawalgandSingkawang,
PontianahBanjarrusi4 LakeIamuda (?} KapuasRivo
(1993) added
aodMuara Tebeh(=Teweh)aslocalitiesfor tlre speciesin Bomeo. Sebastian
Ifutai National Park', Gurung Palung (smounding swanp9, TanjungPuting and Danau
Setarum (Kapuas)in Kalimartan. Cox & Gombek(1985)reportedthat in Sarawak,frlse
gharialscould be found in the upp€rRejang;Tutuh, Suai,Tisak, Set€rap,Kelauhand Dor
(1993)addedthe lowv BaramRiver,foag,an
Riversandthe Ens€ngeiBaki River. Sebastian
BunutandN-{aludam
swampforestto the Salalv"klist.
If plotted on a map of Borneo,manyrecordsle within a geologicalstratun larown as the
KuchingZooe(Figulel; r"anBernmelen,1949),whichfollowsthe northernedgeofthe anci€nt
SundaShield(H. Hazebroek,pers. cornm.;Ilall and Blwdell 1996). this zone ccerds
tlToughweslemSarax"kinto WestKaliourtan in thevicinityoftlrc DanauSentarum(Kapuas
Laket, th€r:l@rvesin a northe€sterlydirectionto enclos€part of the ulu Barito and utu
Mahakam. .?1schlegeli lvs been reliably repoded from most of these sit€s apaft Aom
Singkawang,
the Grlurlg Palungareaand Ta4iungPutingNationalPark. The sum of tiese
rccordsseemsto rcflecta formeriycontinuous,now tragmerteddisributign for Tomislotra i
Bomeo.ilr int€riorwetlards.
Firsthandrcportstom west€rnSarawak8rerumerous,mostofthern Aom swampytributaries
ofthe I-uparandthe SadongRh'ers,srch asthe Sg.' EruengeiBaki (Fig. 2; Tablel). Tbis
vegetationrhokedtributaryofthe Sadong,meand€rsftrcugh peat swarnpsfo! about2G25
kq oft€n obstruct€dby floatingrnatsofvegetation.Cox andGombek's(1985)ordysighting
ofthe speciesoccunedin the &uengei Baki, whereoneofus (EL) reconfirmedthe stiistenc€
ofthe speciesdruinga 1996srrvey. In late Mad\ 1998, residentsof KampungEnsengai
Baki related6$1handsighti€s of T, schlegeli,d'eAf.trte
the permaner*loweringofwater lsvels
by two metres,beoause
ofa recqt drainageploject.
Anoth€rrecqt reood of T. schlegeli odgirEtesfrom a sitenearthe to*r ofEngkelili (1" 12
N, 111" 40 E) andin the Sg. Tisat alsoa Lupar tributffy. In Augus! 1994,at Sg.Runjilg,
E'lgkelili, two adult false gharialswere sigbtod,and about two weekslato, a threemeter
fenale was capturedaJher nestby Sarar"k NationalParksand Wildlife statr(ading and
Stuebing;1997).In the Sg.Tisakon Cbdsftus day, 1996,an lbanwomanbathingat thejetty
ofa log pondwas seized(probablyby a Crrcdylus porosrzs)andkilled. H€r r€rnainswerc
found the ne){t day about one kilometer upriver. Severalclals after the incideff, an
apFoximately3 m long T. vhlegeli fvr/]alqvth 20 partiallydwelopedeggs,lras caughton a
hook and killed in rwengefor the wornan'sdeath.Its stomachwas found to containa srDall
amournof humanrernains(nose,lips, somehair). The mostrec€ntlocaliryin Sararakis was
reponedin Aprt 1998Aom the upperSg.May€ng;a tribut ry ofthe Sg.Kakus(M. Gun4
pels.coltm.). A compilationofthe mostrec€ntinfomation on the distnibutionofthe species
in Sanwakis civenin Table1.
' Alparendyar error(R Blouch,p€rc.Colnm.)
' sg. = sungi (river)
ef:
I
.,_*
'.\
::-'"b,
SARAWAK
i',/tt),
Tit
'''/
'r':
'/,,.kt
;-''..a--,-{
I = confirmedrecord
? = unconfrrmed,
doubtfirlrecord
xxxxxx
Figure l.
= Ourlineof&e KuchingZone
Approximate distribution ol Tomistomaschlqgeriin Borneo in relation
to a geological
feature,the.Kuching Z,one"ofVan Bemmelen
(1949).
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Cox & Gombek's(1985) recordsof T. schlegeliftom the lower Baramin the northw€st,
includhgthe searcnallake,Loag;anBunut(alsomernionedby Sebastiarl1993),arc doubtful.
andrr|ayrepresenteithersmallnon-viablepopuldions,or l"grants, in sluinkingpocketsof
habitat.A visit by one of us (EL) in 19% could not confirmits existenc€therevia dirccl
zurveys,andcornrnerns
&om localpeoplewerevague. Both ofthe Mukah recordsarebased
on old rmrsanmspecimens,
one tom the SarawakMusorm and De Rooij's from L€id€n.
Therehavebeenno reportsof T. schlegeli frorn the Mukah areafor suny yean (C. Tyller,
NPWO, pers.comm.). Thoe are few reliablereportsof the speciesoccrmingbeyondthe
MaludamRivernearthe LuparRiver. The only recerf confmed brcediogpopulationof&lse
ghrxialsfrom qstern Sara*akexistsin theabovenentionedSg.Mayeog.
Table 1. I,ocditiej fot Tornistona$chlegdi in Saiaryak
Ircdity/River
Sourte*
Sg.Enser€EiBaki
Sg.Kerang
Sg.Seterap
Sg.Kelauh
Sg.Dor
Sg Runjing
Sg.Tisak
Sg.Mayeng(Kalos)
Sg.Mukah
Loag,atr
Burut
Sg.Ba&rn& tdb.
1,6
6
'It
I
I
4
Strtus*'
B
B
B
B
B
6
1'
)
2
c
Corrm€[b
Mults andjuveniles
Aduh caughtandreleased1997
Crocdlltls porosus!.'ewnt
Croc@lus poroats pre*m
Nestingfemalgtwo adults
Croco.rlusporosuspresrrr't
Flyingfox zurvey
Extirct?
Crocdylus poroslrsV esrLt
Crocdylrs porosls prffit
t
f =DeRooij,f9l7; 2 = Cox& Gombek,
1993;3= SurvEFbylading,19%-97;
=
=
4 Ladinga4dStuebing;1997;5 M. Gunal (!ers. comm.);6 = 1998survels
*'r A= Cjo4fumed
sighting;B= Reportsby localpeople;C = S€codhalldreports
(pres€bc€
doubtfiD
EABITAT
Themajodtyofrecolds of T. scdegeli mSuawakaxefrom peatswarnpsformedin the interior
tributariesofrhe Sadonglxpar and TatadKakusrivers.Vegetationis composedofa giart
spff,iesof P@dorus,andtheriverchamelsareoftenblockeddebris8rd by large0oatingnats
of Hagaoa nalalwa, and now with srotic wato 1r1'acinth.
Basedon the irtensiveishiug
practicedin thesecotree-colou€ddv€rs,fish evideftb rernainerfenely abudatrt.Fishspecies
barvest€d
from threeivers with lolownpopulationsof T. schlegeliareli*d inTabh 2.
Fo! oestingareas,aotrditionsobs€rvedat the Sg.Ruojingnestsuggesttbal forestcov€ris an
importantfeatureofnestingareas.Unlike C poroats, T. schlegeh apparendyavoidthe su1
andifgiven the opponunity,chooseto rcstin the shadewher out ofthe water.
IYESTING
In July,194, a farmernearEngkelili,Sarawak0' 08' N, 1I I " 39' E) wascleatioga plot for
wet ric.eandcameupona Tmislorrraschlegeliguardinga moundofleavesandotherddris on
a bank of the sg. Rutliiqg. Detailsof this rcst baveb€enrepofi€delsewhue(,ading and
Stu€bhg;1997),but the basicfedures will be mentionedh€re. The n€stu,asconstruct€d
underanapproxioBtely5 n highcanopyin distubedpelt swampforest ar thebaseofa tre€
Trble 2.
Fish speci€sof economicsignilic$c€ in thrce rivcrs w\qc Tornistlrrr4
rc[rqgdi is known to occur
Species
Sc.
Elsclgei
Brki
Blau
Udun
Bo€ng
Acloog
Biavan
Baug
L'ldcrobrachhm,
rosenbergii Udanggalah(pnwn)
gourutti
Kalui
Osph'onetrrus
Bantak
Osteocult/s
sp.
Betutu
Oxyeleotrisnqm<trota
+++
Clwvaq.
Chqva striqt4
qogon
CycLrcheilichtlrys
Hqt rpqla macrolepidota
Helosk rraW.
Hemibagns qp
Ptttttits collingwodi
Rab<n'a qp.
KQrat
Eueluai
Wallagosp.
Tapah
Sg.
Kcraq
Sg
Setersp
++
++
+
++
t
'l_
+++
-i+
++
++
+++
about2 m ftom the strearnbark about1 m abovea snall strearn. Thenestmat€rialsdiff€red
fronthx of C. poraws, becauseoo grasswas used ad the rDain@t€dals were dry leaves
andwoodydebris. The &ls€gbarialoestuas not built asa isolaredmoundoike rcsls ofeost
C.porara), but wascolsuqted at tbe bas€ofa &e€in relaivelydeepslude.This situario4if
h plor'€scoruistent,may meanthat the heatgenentionand dissipaioncharatl€ri$icsof Z
schlegeli ne,F,ts
difer siglificady from thos€ of C- poross lests. The Sg. RDqiingnest
reseurbled
thar of a megapode(Megqdius cxtntiingA seenon Pular Tig4 in Sabah The Z
rcNegeli c\tct. sxzewas 16, and after the eggswere r€orcrcdin mid-August the relarivety
docilefenale l,as captu€dby statrof the Wildtfe Sectionard trdDfenedto MatangWildlife
CedrenearKuchitrg.
The Jorg CrocodileFarm on the outskfutsof Kuching, Sarawakciur€oly holcls39 false
gharials,most of which were obtainedtrom tnbuuries of the Sadory River, ircluding the
Ens€ngeiBaki, Keraq(an) and Sinunjan. Sweral maleshavebeenin captivityfor 30 yeaxs,
while severalof the fernaleshave be€nkept for about 18 years.Irtuestirgly, Tontisonto
schlegeli,w\ke CftEdyluspolo$ar caob€ kept in mixedgroups(sizeandage)with minimal
aggressive
irteraction.. This diFerencein captiveanimalsmay imply differencesbetweenthe
two species
in thewild in t€f,msofsocialirteEctionsandterdlorialdefense.
lnthefuoarlte T. schlegeli havesurvivedwell andhavebeenobservedcourtingandmating.
Ofa total offve nestsov€r the last four yess, all havebe€nconshucted), betweenMay and
July (19 197) by a singlepair, a 2.6 m femaleand a 3.2 m rrnie. Nest construction
commencedaboutsix monthsafter the farm enclosurewas modifiedto simulateconditioru
se€nin the 1994Engkelili nest. Eggs were subsequently
laid in four ont of five nesting
atternpts,with froo| 12-23eggsp€[ nest,but only onehatctrlingwasproduced.The reasonfor
the low fertility is not lnown, afthoughthe relativelyyoungageofthe malemiglrt be a &ctor.
Thehafcl ingthafwasFoducedgrew to a lgrlgthoffl crnin approxiflat€lyoneye3r.
L,EGAL STATUS
Tomislomaschlegeli1slistedas a ProtectedSp€ciesuoder Scheduletr of the SarawakState
W,ldlife ProtectionOldinarlce(Anonymous,1995). Uder this regulatio4 no p€rsonnuy
'ltrutt, kilt captug
se4 otrer for sale impon, oport or be io poss€ssioo
of the live animal
fophy or fl€sl/organe)(c€ptund€ran acrordancewith the termsandconditionsofa lic€ns€"
issredunderthe Ordirunce. Tbe pemlty is a 6ne ofRMl0,000, and imprisonmertfor one
year. Lic€nsefeesto o<polt o! to hold h captivityare RMl0.00/head4/r. Expofi of I
schlegelialfo rqwres,CTIESctrdfication.
TEREATS
Hunling
Fals€gharialsarenot aslikely to b€ hurted asC.polo.rr.r,asthe skin olrelttly haslittle value
in the local market. tlatcbling or jwenile I scl/e6elrusedto be sold ho{e!€r, in the Balai
Ringinarea. Cox & Gombek(1985)rerurked that the tradeaJthat time probablynnnbered
'1esstbanteo anirnals'. It was probably
srbstantiallymorethanthat the4 and p€rhapseven
oow. Onlycareftl surv€}l atrdcoopentionfiom localpeoplecanshedlight oo this. TheJong
AIm k€€psa s$staffial oumb€!of I &hlsgeli :ol,Aerlicgol€ obt,i'rfd 2045 yea$ ago from
theulu Sadongare4 possiblytrornthe Sg Ens€ngaiBaki andthe Sg.Kerang.
Fishing
Cox & Gombek(1985)ergres^sed
concernoverinteruivefisling in riverssuchasthe Ens€og€i
Baki. Fishingis cari€d out via the useof deepselonbet rretsW to 30 metresin lengtll which
arecormody op€nedacro$smaindver chamelsor mouthsoftributaries. thes€ rcts €r$irely
blocka channelandif the villagersr€portthat lll:o;crats T. schlegeliaredrownedasa r€$lt.
The ,€&d net takesadvadageof tidal fluctuations,an thoughlesslikely to trap an aduh Z
schlegeli,cclid, tq juveniles. Somefshermenregardfalsegharialsas a rnrisanc€,hlling
belief
themanddiscardingthe carcasses.Othelswill releasethe animalsout ofa superstitious
that crocodilesshouldnot be distuM. Ilatcl ingsarenot aslikelyto berelease4howwer.
The useofpesticidesfor fishinghasoccurredin rec€ntyearsnearSedar!vltin T. schlegeli
habitat(A Fong;Pers.Conm.). this practicehasnot beendirectlylinkedto anydeclineof Z
sc egelipop,iations,htt the lotrg-t€rneffectscouldbe s€rious.
CONSERVAIION
Until htensivesurvqs in Sarawakprove otierwise, Tonistota schlegeltsfuitld be regarded
as tlreatercd. From the most rec€{t spotligh s.rveys and intervie*s witb local people,
densities
offalse gbarialss€emnth€r low, thougha&nittedlythe animalsarc alwaysdificult to
detect. A rnatterofgaat conc€rnfor long-t€rrnsuryivalT. schlegelipo4tltions is the impatt
riversin Sarawak.Thenain arcaof
of landdeveloprnedon pe3tswampsad thei associated
conconis specifcallythe axea&omSeriatrto ElEkelili. Existinggovemmqf laflts still codain
mall forestres€rves,
but tll€ r€rnainigareasarelikelyto undergodw€lopm€ntfor agdculMe,
anddrainedvia the construciouoflorg; parallelchamels. Z scllqeli populationsoristingin
pdvatd heldlands(mosttyundernarivetide) InayAc€ a blsk futureaswe|l shcemarlyp€at
swampsarenow targetedfor cotN€rsiorto oil palmplafltdions.
Cuneoily,thereareno giazsttedparksor protectedareaslying within the cale distributionfor
T. schlegelim Szra\\zk The MaluriamWildlife Sanctuary(8,700ha),wh€reT. scuegeli lrtzy
occur, hasbeenon the propos€dlist for ser€ralyears,but as of earty1998hadoot yst been
gazetted3.
This proposedSanctuarymay, in &ct, lie outsidethe areashistoricallyhavingthe
W$t densityof T. scuegeliin Sarawak.
To reiterate,most ofthe areaswherc T. schlegeliI&s ti*oically beenabundar*areur ikely
candidates
fur protectio4 sinc€theyalreadyfrl underoth€rcategpriesofland us€. A multiple
usearfingemel$is probablythe bestsolutionto this tlilesur4 involvingaclivemaDagemqt
fshing practices.
Coosiderable
consen"tiod efon hasbeqr underwayduring the last few y@rs,to promote
legislationto discou€e all forEs of hrmtingin Saxawak.Unforhtatety, speciesslch as
us€ of resourcesand
Tonislona schlegeli will b€n€fitmore from guidelineson sustainable
gharid
habitatnust b€
offalse
wiselanduse,ratherthana banon killing. The disappearance
halted,followedby ivofu€mmt ofboth gov€rnm€ntandlocal corrnuoitiesin rnanagemetof
thisuniquewildlife resource.
ACKNOWLEDGEMENTS
Our thanls for the help and support of CheongEk Choon (Director, S'arawakFo!€st
t Maludambas,in Act been
Foposedprifiarify for thecorsenationoflrtds ard pri&ates(Gual and
Ablrad 1995).
Departm€rt),Saiun AhrDad(NationalParla and WrldlifeOfice), Mcbael Megang Almad
AmpengandStephenSungan(SarawaLFishedesDeparhnent).
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Anonlmous, 1990. Wildlife kotectioo Ordinance,State of Saraw"dk. State Attomey
General'sCharnbergKuching Sarawak.
Anonlmous, 1995. Wildlife Plotectio! OrdiDa&e,1990(A[!€ndm€rf), Stateof Sarawak.
StateAttomeyGeMal's ChanbergKucling; Sarawa&.
Co4 J. and F. Gombeh 1985. A preliminarykrcwn srrvey of xhecrocodileresourcein
Sarawak,EastMala)tia. ruCN4VWF ProjectNo. MAL 74185.World WildiifeFund
Malaysi4Kualalurnpur. 62 pp.
in Sarawak'sTotallyProtecl€d
Gumal,M andS.Ahma4 Gnpress).Biodiversityconserrration
paper
presented
Proceedingsof the
Areas Past, presentand fittule. WolkiDg
1995.
MalaysianFor€stryConf€rence,
M'Ii, Sarawak,Nov€Nnb€r,
IIa4 R & Blundell,D. (eds.),1 . Teclonicevolutionof Sodlv6t,4rt4 Geol%ic€lSociety
SpecialPublicatiorNo. 106,pp. 153-l&. London
Stu€bing;R B. and E. Irding, 1997. N€st ofa frlse gharialtom Sarawak. IUCN/SSC
Crocdtle SpeciqlistGrovpNewsletter,16(2)t12-13
Rooij, N. de, 1915. np reptilesof tlre lrrdo-Austqliqn arcWago. L Lac.crtilia,Chelo!4
Emydosauria.E.l Bri4l€id€o. 381pp.
A, 1993. The Tomistoos or &lse gharia[ Tot,inorra schlegeli: The oeedfor its
Sebastian,
Asia" Proc.2ndReg.Meetingsofthe IUCN/SSCCrocodile
cons€n"tionill Southeast
SpecialistGroup,Daryin, NT., Aushalia12-19Marcl! 1993)
Van Bemmeler!R.W., 1949. The geologr of Indonesia(Vol. Itr). Gov€rnm€ntPrinting
Oftce, Thellague.
The FalseGharial (Iot inoma schlegelAin S\ ^tra
Mark R Bezuijetr'r,GrahameJ.W. Webbr,Pardu gartoyos'Samedi',Widodo S.
Ramono3and S.Charlie Manous'
rlvildlife ManagementIntematioDalPty Limite4 PO Box 530,Karama,NT Austalia 0812; '?Cutrent
Ecology Austalia W Ltd"272-276ll.1delb€xgRoa4 FairEel4 victoria, ABtralia 3078
adalress:
3Dircctorate-Geaeral
ManggalaWanabaki Blok VII Lt. 7,
ofForest Prot€ctionandNatue CoDservatioD,
Jalarta Pusat Java.hdotresia
Abshaci
The False Gharial (Tomistoma schlegelii) i.t one of the world's least-known
erocodilians and is consideredto be globally endangered. This paPer presents the
results of a lesearch proiect undertakenfrom 1994 to 1996 to assessdistibulion,
abundanceand ecologt of the speciesin Sum1ffa. Thespeciesis cltfte ly distlibuted
population in
from North Sutata to South Sumatra Provinces, with 4n ^ol^ted
in
Lampuhg Proince. Eistorically, the species occarred
freshwater ecosystent
throughout most of eastem Sumatra,and its cwrent distributiort representsa range
decline of some30-40o1. Local people repolt a decline in distnbution and abundance
owr the last 30-40yeart, coinciding with increasing lossoJnestinghabitat and hunting
species
for the skin trade in the 1950s-70s. It has always been consideredthat the
wete
26/Ion)
occafted irl low densities. Thehighest recordeddensities(0.21/lanatd 0
on the Merang Ri'ver (South Sumatra Provitce) and Berbak National Park (Jambi
Province) lespectively, where bteeding populations w*e confrmed to occur'
Tomistomaschlggelii wasfound to forage and nest in at least twoJorest categoriesit1
Sumatra,peat $lamp forest and lowlahd seco dary folest. Nest and egg dimensions
egg mass is almost double that-of every other
are presinted. O7 iigttiTc*"",
croidilian species. Th" globol ruCN ttotus ofthe speciesis Data-Defcient, b'tt withitl
Sumatrathe speciesmay be consideredto beEndangeredor Citically Endangered'
Itrtroduction
The False Ghaial (Tomistoma schlegeli, is one of the world's least-Lnown
crocodilians,and is listed asthe fifth-highest priodty speciesfor conservationaction by
the IUCN-SSC Crccodile SpecialistGroup (CSG) (Thorbjama$oo 1992) Originally
widely <tistributedin South-EastAsi4 the only populations are now- known from
Sumata and Kalimaltan (Indonesia), Saxawakard Peninsular Malaysia (Malaysia)'
'Data-Deficient' under the IUCN (1994) citeria'
The formal status of the spe.ciesis
Sebastian(1994) receutly emphasisedthe treedfor clarification ofthe curent statusand
distdbution of the species.
Lr 1994the CSG initiated a project to assessthe conservationandmanagementneedsof
T. schlegelii. Wildlife ManagementIntemational (WMI) agreed to co-ordinate a
cooperativeresearchproject on the specieson behalfofthe CSG with fimding from the
Gl;bal GuardianTrus! sTvII, the GermanLeatherIndusky Association(Intemationaler
10
R€ptillederverbard-IRv), CSG and the Asian Cormervationand SustainableUse Group
(ACSUG). Additional staffand resourceswere providedby WMI.
With the largest remaining populatious thought lo exist in Sumata and Kalimantar
(Cox 1987), researcheforts were dir€cted at Indonesia. A co-operativeproject was
initiated with the Dire.ctoiate-General
of ForestProtectionand Nature Conservationof
Indonesia@HPA), which has identified Z schlegelii as otre of the most endangered
clocodilials in Indolesia (Ramouo and Raharjo 1993). Fieldwork was resEicted to
Sumatrain order to maximisethe amountof informatioo obtainod&om a single, large
area.
The aimsof the project were:
.
to locatearcaswith breedingpopulationsof T. schlegeliit
.
to obtain a broad overview ofthe curent and historical distdbution, abrmdanceand
statlrsof T. schlegelii in Sumatra;
.
to conductsuweys fot T. schlegelii iniver systemsin easteroSumatra;and
.
to collect asmuch additional information aspossibleort the eaologJof T- schlegelii
itr Sumat4 including aestingbiology, morphometricsand scalatioq diet, histodcal
tade and local beliefs.
This paper describes the results of the ploject, undedaken ftom 1994 to 1996.
Conservationandm:r:gemeD:tof T, schlegelii in Sumata is discussed,
Study ar€a
Sumah4 the secoud largest island of Indonesia (after Kalimantan), extends fom
5o40N,95010'E(norttremtip ofAceh Prcvince)to 5o55'S,106o0OE(south-eastemtip of
Lampung Province). The island is divided into eight provinces (Fig. 1). Westem
Sumata is dominakd by the Badsan Mountain Ranges,a large chain of mountains
which extend from the northem to southemtips of Sumatra. ID many areasof western
Sumat4 only a narrow stip of coasbl plain separatesthe mountainsftom the Indian
Ocean. Riven in westem Sumata are relatively short, rccky and drain west into the
Iodiar Ocean. In coutast, eastern Sulllata is dominated by large plains of low
elevation,charactedsedby loDg,meandedngrivers which drain eastinto the Malacca
Stait. Mudflats and extensivematrgrovesystemsdominatethe eastemcoast
The climate of Sumatravad€s coDsidcrablydue to its varied topography. Average
annualrainfall is 2500 mll], but ratrgesiou 1500om (someareasofeastem Sumata)
to 6000mm (west of the BarisanMountains) (Whitten €t a/. 1984). EastemSrlmata is
chancterisedby a poorly defined wet seasonlasting 7-9 months (October-April) and a
dry seasonlasting 3-5 months (May-Septembet).Mean aanualtempemturesin easterr
Sumatrarange trom 23oCto 3l'C and meanannualrelative humidity is 85% (Whitten
et al. 1984), Itr eastemSumatrathere is usually onetidal cycle per day, but can be two
po day during neaptides. Tidal range can be up to 5 m in some areas,but is highly
ll
vadable;tidal influenceextendslvell upstreaminto totally ftesh walet a\eas(Hadr et al.
1977).
Methods
Field suweyswere couductedin Sumatlafiom 1994to 1996. In 1994,preliminary field
trips and interviewswele conductedin SumatraatrdEastKalimantanProvince@amono
1994). In Malch 1995 a trip was made to South Sumatra Prcvince to ascertain
fieldwork logistics and identiry areas for rcsearch (Bezuijen et al. 1995a). Two
extensivefield trips to Sumata were undertakenfrom August-October1995 and JulyOctober 1996 (Bezttijen et al. 1995b, 1996). Fieldwork and methodsare describedin
Bezoiie(Let al. (19954 b, 1996)andare summarisedbelow.
Interviews. Interviervs with fishemerq fonner crocodile hunte$, Foresky officials,
reptile skin tradcrs and clocodilo farms werc a key sourceof inforlnalion. Prcvincial
Department of Forestry records of T. schlegelii sightings werc accessed. A
comprehelsiveinterview (consisted format) covetedT, schlegelii distribution (cunent,
historical), abudance (changesin number and size stucture over time), taxonomy
(diffelent colour forms), uestingbiology, local customsand beliefs and historical trade.
Interviewswere cotrductedin all provincesof Sumatraand infomation was obtainedon
a total of27 river systoms. Histodcal atrd curent distibution was defined as records
prior to I 990 and after (and including) I 990 respectively.
Szlveys. Surveys for T. schlegelii were conductedon ssveral river systemsin eastem
Srunata, by speedboator canoeusing a spottight 02 V battery) or torch (6 V battery)
respectively. 'Eyeshines' were assumedto be T. schlegelii unlessthey were within a
few kilometes of the sea and in blackish lvater, where they were assumedto be
Crocodylusporosus.
Capture, morphometrics,scalation and diet Attempts werc made to captw€ all
irdividuals sighted. Scale counts and morphometric data were recorded. Stomach
conterts were removed following Webb et al. O982). To aid with analysesof li
were collectedfrom the Merang River
schlegelii stomachaontents,fish and crustaceans
in South Sumatra Province, Incidental obs€rvations of mammals, reptiles and
anphibianswere record€d.
Nesting biotogl. Sidecreeksand mainsaeambauks wele searchedfor nests. Nest
dimensions,uest habitat, clutch size and egg dimensions were recorded. Where
possible,one egg ftom eachnestwas opeDe4preservedand enrbryoageestimated.
Habitot quantifcatior. To quadiry the foraging and breedinghabitat of T. schlegelii,
forest q?e, stucture, dominant ttee species,river lengJh,depttt temperature,salinity
andpH were recordedon most rive6 surv€yed,
t2
Resultsand Discussion
Histo/ical distribution in Indonesia
In lndonesi4 the speciesis known historically Aom Sumatraand Kalimantan. The
specieswas fomrally describedfrom Kalimantanby Muller (1838) and later Boulenger
(1889), and the first Z schlegelii wasbro\ght to the Zoological Gardensof Amsterdam
in 1890(de Langeand de Rooij 1912). Thereare no histolic r€cords&om elsewherein
Indonesi4 except for a museum specimell with the coll€ction locality as 'Java',
althoughthe sperific locality is unhown (Strauch 1866, as cited by do Rooij 1915).
Stauch did not seeany oIr Java (de Rooij 1915) and it has never been reported there
since. Mountain rangesand oceanic isolatiotl may have preventeddispersalto other
Indon€sianislands(e.9.the NusaTenggaraislandchain eastofJava).
In Sumatrq T. schlegelii has only beenreported from provinceson the castemside of
the Barisan Mouotains: Acei! Jambi, Lanpung, North Sumatra"Riau ard South
SumatraProvinces(Fig. 2). Most historical rc.c.ords
of T. schlegelii are from the central
andsouthernprcvincesofJambi, Riau aqd SouthSumatra(de Rooij 1915,de Lange and
de Rooij 1912,Sudharma1976). Thereareno recordswest ofthe BarisanMormtainsin
West Sumatla and Bengkulu Provinces, as this mountain lange probably prevented
dispersal ftom eastemSumata, It is unlikely that the spe.ies has ever occurred in
westernSumatra.
Pdor to the 1950s,T, schlegelii appea$ to have occurr€dfiom south-eastemAceh to
LarnpungProvince, ahnostthe sntire length of eastemSumatra(Bezuijet et al. 1996).
A sighling i! Aceh Province by a Foresty ward€n in 1993 was the most northerly
record reported (Bezuijen et al. 1996). A record from the 1960s in North Sumaba
Province near the border with Aceh Province indicatesthat until 2G30 years ago, T,
schlegelii occurreAin uorthem Sumata. If the 1993 r€cord from Aceh Province is
coofimred, this would exteud the historical (and possibly culrent) range by
approximately400 kn oorth. There are no mormtairrrungesexterding to the coastal
plain in southemAceh which might haver€stricteddispersal,and it seemspossiblethat
the s?eciesmay have occu8edin southemAceh Province. In conhast,a narow coastal
plain is presentin northem Aceb, boundedby the foothills ofthe PusatGayo Mountain
Range,and it seemsudik€ly that the specieswould have occunedthis far nolth, due to
a lark ofupstean, freshwaterhabitat,
ln Kalimantan. thorc are histodc records Aom Central. East and west Kalimantan
Provinces,wherc the spe.ies appeaBto have beeu widely distributed (de Rooij 1915,
Flazier andManuborgs 1990).
Cufteqt distibution in Indorlesia
The o y known breediDgpopulationscurrendyin lndonesiaare in eastemSumata and
central, e-astemand westem Kalimantan. Thqe are unsubstantiatedrepolts from the
early 1980sftom north Sulawesi(Thorbjamarson1992), althoughthe occrlrrenceofa
breedingpopulation on the island seemsun.likely,given its isolation Aom Kalimantan.
Thereareno recordsofthe speciesfrom Javaandthe NusaTEnggaraislands.
ln Sumata, post-1990rcports of Z schlegelii were rccordedftom local fishermenand
othe$ ftom all eastemprovinces: Aceh, Jambi, Larnpung, Nodh Sumatr4 Riau and
South Sunatra @ez]ijer. et a/. 1996). Seventy-eightrecords of T. schlegelii werc
rcportedby interviewees(24 pre-l990 and 54 post-l990) @ezuijen et al. 1995b,1996).
The majodty ofpost-1990 recordswere tom Jambi (26), Nau (11) and South Sumata
Province (8). R€cords of I schtegelii sig}ljrn1sin Sumata held by Asiar Wetland
Bureau-Indonesiaar€ ftom fuau (8), Jambi (5), South Sumatra (2) and Lampung
Province(1), ofwhich 10 arep!e-1990and6 areposrl990 (AwB-IndonesiaDatabase,
September 1995, unpubl. recods). Records of T. schlegelii obtained by other
rcsearchersaremost commonlyfrom Jambi,fuau ald SouthSumata Provinces(J. Cox,
FAO-PHPA Crocodile ResourceManagerrentProject unpubl. dat4 Muin and Ramono
1993b,1994).
1994,Raurono1994,S€bastian
Curierrtly,T. schlegelii is thoughtto occur from south-eastemNorth SumstraPlovince
to southem South Sumatra Province, with an isoLatedpopulation in Way Kambas
National Park in Lampung Province (Fig. 2) @ezuijen e, al. 1996' Sebastian1994)'
which probably representsthe southem-mostextent of the species' current range in
Sumata. The fiIthest west the spe.ieshasbeenrecoldedis the eastemfoothills of the
Balisan Mountain Raugesin West Sumata Province @eaijer. et al. 1996), which is
probablythe westem limit ofits rangein Sumata.
Basedon a slmthesisofthe aboveinformation andby compadngthe approximateareas
encompassedby the histodcal and current lauge (Fig. 2), it is estimated that the
distdbution of T. schlegelii in Sumatn has contacted by 30-40% in the last 30-40
years. Jambi,fuau and South Sunatra Plovinces are the stongholds of the speciesin
Sumatra.
Statusin Sumatr.t
'Data Deficient', due to insulficient
The IUCN-SSC status of I schlegelii is
infodration to enable au assessmentof the global risk of extinction, basedon ruCN
(1994) criteria- This situation is largely unchangedon a global basis, but data from
Sumata indicates that the speciesmay meet the IUCN criteria for Endangered,and
possibly Critically Endangeredwithin Sulnatla. Data fiom the surveys oonfirms the
high priority listing given by the CSGto the species:
.
there hasbeen a documenteddecline in the distribution of X schlegelii in S]J'J].afJ|a
over the last 30-40 yeals, dudng which the species'total rangehas contractedby an
estimated30-40%:
.
there has been a documenteddecline in the extent and quality of habitat for I
schlegeliia Stt'jLatlah the last 30-40years;
o the nfrmberof mature individuals and subpopulationswithin Sumatrahas declined
in the last 30-40 years;
.
T, schlegelii pop,Jlationswithin Sumatraand Kalimantan arc sepamtedby mountain
rangesand oceanandmay be isolatedftom eachother.
Abundancein Sumatra
Prior to the 1950s,the specieswas consideredrelatively abundartby former crocodile
hunterc. Therc are no quartitative data to indicate the speaies'historic abundance,but
interviews with fishermen and former crocodile huntels suggestthey have always
occured at low densities,althoughthis may be partly becauseI schlegelii is r]:otlnr\own
to folm large aggregationsard appea$ to be a particularly shy crocodilian. De Rooij
(1915) folmd th,i T. schlegelii was 'not rare' in SumatranriveE and Muller (1838)
statedthat it v/as 'fairly abundant'in Kalimantan.
Surveyswere undertakenon l0 rivers and their tibutaries in Jambi, Riau and South
SumahaProvincesin 1995ad 1996 (Table 1, Figwos 3 al.d 4). Tomistornaschlegelii
vr'ererecordedon ody two dvers, in Jambi and SouthSumata Provinces. The highest
mean density of Z schlegelii rccorded&lding surveyswas 0.26 individuals,4cnoll the
Air Hitam Laut fuver in BerbakNational Park (Jambihovince) in 1996(Table 1). No
T. schlegelii were rccordedduring spotlight surveyselsewherein South Su1natrqJambi
or Riau Provinces (Table 1). However, suwey conditions were not ideal on several
occasions(e.g. high water levels afrer rain). Local people reportedthat T. schlegelii
occurredat low densitieson all l0 ofthese river systems.
Table 1. Spotlightsurveyresultsin SouthSumata(SS),Jattbi (J) andRiau@) hoviaces,
1995-1996.Resultsreferto fonErozd tcrlegertitmlessrnarkedwith'+' (Crocodyhs
SlrrnaFa,
porosrs).ES= Eyeshine.Ahl = Air HitalnLautRive! andSimpangMelala Cleek(Berbak
NationalPark). Btg= BatangEali River.FIomBezuijener4l (1996).
Yr
River (lsn $rveyed)
(ft)
Sizeclasses
Prov
2-3
34
4-5
ES
5-6
Total Densiry
>6
95
Melzlg (045)
ss
3
95
Meraq (46-66.5)
SS
5
96
Merang(0-45)
SS
96
Merary (4666.5)
ss
95
Medak(G53)
95
Medak trib's (321m)
95
7
'7
0.16
1
2
0.04
5
10
0.49
SS
2
0.03
0
0
Irlan (0-160)
ss
ss
0
0
95
Kepatryaae(G16-5)
SS
0
0
96
BeDu(0-38)
ss
0
0
96
Afl (0-27)
I
7
o.26
96
Btg (325-465)
J
0
0
96
Alai (4-9.5)
J
0
0
96
Tes;(o-la)
Kubu(26.5-34)
R
0
0
R
0
0
96
21
-l
0.34
The Merang River (South Sumata Province) was surveye.din 1995 and 1996.
Spotlight-court densitiosotr the Merang River rangedfrom 0.04-0.49individuals,4<m.
In the downstreamsectionofthe MerangRiv€r (km 045), densitieswere lower in 1996
than in 1995,but in the upstealll section,.wcrehigher in 1996than in 1995 (Table l).
The overall densities of Z schlegelii seat along this river (sectionscombined) were
0.21,4snin 1995 and 0.18,4snin 1996. The Merang fuver is tidally influenced along
kn 0-45, wherebanksare offen clear ofvegetation and the mainsaeamis more than 30
m wide, Foviding good survey conditio$. Atong kn 46-66.5, the banks are densely
vegetatedand often only sevenl metes rvide, and survey conditions are poor. The
survey dansitiespreseDtodhere provide an index to population fluctuations,nther than
an indication of absolutepopulation size. Caution is rcqufted when interpreting these
data,due to the low numbers. Oneother surveyof the Metang fuver was conductedin
1990, by J. Cox, whq recorded the same density of T, schlegelii along km 0-23
(0.04r<n) asthat recordedalong km 0-45 itl 1996(TablesI and2).
The few datawith which to comparethe abovedensitiesare unpublishedrecordsor are
included in the results of brcader crocodile surveys, and do oot present specific
densitiesof
schlegelii- Tlte raw data fom thesereports have been extractedand,
wherepossible,tho specific densitiesof Z sci legelii calulated. Table 2 summarises,i
schlegelii dansitiesrecorded in other oocodile surveys in lndonesia ard Malaysia.
De\sities of T. schlegelii recordedby other researchersare of similar magnitudeto those
in Table l, and most densitiesappearto be low. Irnnediately apparentis that the
highest densities of T. schlegelii are ftom three locations: the Merang River, South
SumatraProvince (highest overall density of 0.21 T. schlegeliilkm in 1995), the Air
Hitam Laut River, Jambi Province (highest overall density of 0.34lkn in 1990) and
DanauSentarumNational Park, WestKalimantan(0.12lkm in 1994)(Tables I and 2).
Table2. Summaryof Z scllegelridensities
recorded
by otherresearchos
duringcrocodile
=Air
suveysin IndonesiaandMalaysia.Al
HitamLautRiver,NP-NationalPark.CK, EK atrd
WK{entraL EastalldWestKalimantanProvinces,
SS=South
SumatraProvince.Es=Eyeshine
(assiu$ed
to be T.schlegeliifor this summary).Km = totalkilooehessurveyed.
Surveyd.te
No,I
schleselii
MeIary River (sS)
S?90
I
22.75 0.04
J. Co& i! litt.
MedakRiver (SS)
Sep90
2 (ES)
36
0.06
J. Cox, in litt.
Lalan River (SS)
Sep90
2
150
0.01
J. Cox, in litt.
AlIl (BerbakNP, ,
Oct90
7
20.5
0.34
J. Cox, in litl.
severaldvers (EK)I
Aug-Sep90
5
156.8 0.03
Frazie! & Matu$ongs (1990)
s€veraldvels (CK)'
Sep-Octgo 19
802.5 0.02
Frazier & Matubongs (1990)
DaDauSeqtarumNP (WK):
Aug94
6
51.9
0.r2
Frazier(19t4)
Jul-Sep85
3
102
0.03
Cox& Gombeck(1985)
Locrtion
D€na Source
Sumrtra
Kalimrntrn
Sarawak
l6
'Total suryey length derivedby addingaI km surveyedbyF&M (1990) exceptfor 'Tidal-Matrglove
NWa habitat' (assumedto be unsuitablehabitatfor z scilegelt . 4xES in EastKalirnrnta! werc
ass'JE&dta be T. schkgelii for this cdculatioD"
'4xES v,/de assunedto be I rcrl€geli for this calculauon. All si'( crocodileswere seeEon a 7.6 hr
spaDof oneriver (=0.79cocodiles/km).
3All3 T. schlegelii \xerc seelro! a 13km spanofone n.,er (4.23 T. tchlegelii/krt.
Tomistoaaschlegelii is a specieswhich appea$to occur at lolv de$ities tbrcughoutits
cunerf mnge in South-EastAsia. The highestrecordeddensitiesare from tbree river
systemsin Sumatraand Kalinantan: the Merang and Air Hitam Laut Rivers (South
Sumaaaard Jambihovinces) andDanauSentarumNational Pa* (West Kalimantan).
Nestilg biolog/ and habitat
Brceding populationswere locatedon the Merang River (South SumatraProvince) and
confrmed to exist in Berbak National Park (Jambi Province). The presenceof a
breedingpopulationin BerbakNational Parkhaspreviouslybeennoted (Atnoso€dirdjo
1993,MacKinnon 1982,Silvius et a/. 1984).
Sixteensiteswhere U schlegelii tests werc ples€nt o! had be€trpresentwele examined
in 1995and1996(Bezuijen a aI.1995a.1996).All exceptoDesitehadbeenpleviously
locatodby rcsident fishemrenandwere shownto the surveyteam. Fifteen siteswerc otr
the Merang River aad one, a site Fom the early 1970s (shown to the team by the
fishedEatrwho originally locatedit, andwhich no longer containedany tlacesofa nest)
was on a tibutary of the Medak River (South SumatraProvirce) Only three sites
containedintact nestswith eggs. The fifteeDnest siteson the Merang fuver were &om
1996(n'= 2),1995(t=7),1994(n= 1), 1992(n= l)
the followingnestingseasons:
=
and 1987 (n 4). Nest iofomration ftom seasonsprior to 1995was supplied by local
fishermen. Of the sevgn nests ftom the 1995 nesting season,six were intact whetr
locatedby fishermenand 6v€ containedeggs,althoughall five had beel predatedwhen
visited by the surveyteam l-5 weeks after discoveryby fishermen. One site contained
an unfinishednest (scratching9.
Tomistomaschlegelii is a fteshwater,folest-nestingspecies. Nest sites on the Merang
and Medak Rivers were in peat swamp forest. Repo s ofjuvenile T. schlegelii and
nests fiom local fishermen on all othet river systetns surveyed were in lowland
secondary forest, a widespread forost category distinct from peat swanp forest
Structual diffelencesbetweentheseforcst types wasquanlified. Peatswampforest v/as
characterisedby the presenceof well-defined peat moundsalong the banks (fomred by
gradual deposition of organic matt€r arouadtree roots), poody-definedrivel channels
and a ml,riad of short waterways adjacentto the mabstearn, low pH and very low
elevation. This fotest categorywas only recordedon th€ Merang River and Air Hitam
Laut River (Berbak National Park, Jambi Province). Lowland secondaryforest was
characterisedby well-defined river charmelsand river banks,absenc€ofpeat mounds,
dry land adjacentto the river channel(i.e. few waterwaysadjacentto the mainstream),a
'secondary'asvirnrally all
higha pH andhigher elevation. This forestt)?e was temed
folest visited had been logged at some time. All river systemswele freshwater
t1
(although some were tidally influenced) and all interviewees st ed T. schlegelii
inhabitedfreshwater.
The I 6 nestsiteshad the following charactelistics.
.
All were situatedat the baseofa large tree on a distinct peat mound (Fig. 5). Nests
were madeofpeat andwere compact.
.
Nest siteswere direcfly adjacentto (fifteen sites) or 100m away &om (one site) the
mainstream,surounded by a systemof small, shallo$/ sideqeeks (Fig. 5) with a
meandepthof 0.4 m andmeanlength of l8 m in July 1996(n = 228). All nestsites
wele within 2-4 m ofa waterway.
.
Nest sites were in mostly shadedareas,with all nestsin shadeat least 50% of the
day, and 13 nestswhich were in shade80-100%ofthe day.
Threeoestswere intact and containedeggs(l in 1995and 2 in 1996). Nest height (top
ofnest to bottom egg) was 33, 37 atrd 59 cm. Nest basal diameterwas 1.2-1.4m and
the baseswere 1 m abovewater level. Egg and ernbryodimensionsare suumarised in
Table3.
of2 semi-intacteggsfrom a
T.ble 3. Surnmaryclutchdatafo! 3 intactnestsanddimensions
(South
arewith t standatd
Province).
Measulemeds
nes!
Merang
River
SuEatra
Fedated
deviatiod(range,tr). TCM=TotalClutchMass,NT-NestTemperatue,EI{I-=EmbryoHead
Length,EA=Estimated
Ageofembryo(days).FromBezuijen€t d/. (1995b,1996).
Ncst
1Ce6)
Clutch
size
34
Egg mass
G)
Egglery&
(nn)
Eggwidt!
(El[)
TCM
G)
NI
oC
EHL
EA
(Dm,
64.99!t.12 8300 31.8 t3.23 24-25
244!13.11 98.15!2.73
(22r-276, (92.30-t04.82, (63.01-67.90,
F32)
*=32)
a=32)
2('96)
29
23t!4.67
97.19!1.89 63.39!0.70 6692 32.4 34.39 52-53
QLs:236, (94.7GrO2.06,(61.82-&.82,
F29)
F29)
8 C95)
3s
278!'.82
102.a3ji2.44 64.8510.67
(2s3-29s, (97.63109.45,($.n-66.00,
n=34)
tF34)
n=34)
5 ('95)
kedatedrast
8759 3t.4 35.88 57-58
96.44,95.11 57.67,55.46
The nesting data from Sumatra are similar to data collected by other researchers.
Witkamp (1925) recoded tblee T. schlegelii nests in fteshwater swamp forest on
upsteam tributalies ofthe MahakamRiver in EastKalimantanPlovince. Nestswere on
dry dver banks 2-3 m above the v/ater and betweenthin saplings alld modeBte-sized
tlees. Tivo nestswerewithin 500m ofearh other. Nestswere 1.2-1.4m diameter,0.6
m high and contained33, 34 and4l eggs. Intemal nesttempelaturesw€re 3l'C (n = 2)
and 33.5"C(Witkamp 1925). Witkamp (1925) measuredthe dirnensionsof one egg as
103.5om diameter,6l.5mm width and206 g mass,andnotedeggmassto be almost
doublethat of C.poros4.reggsrcceodymeasuledby anotherresearcherin the regiotr.
18
Habitat,proximity to a strearnand dimensionsof a single T. schlegelii nestin Sar". ak
describedby Lading and Stubing (1997) were similar to the nest sites on the Merang
River, althoughthe Sarawakn€stwas locatedat the edgeof a rice field. Clutch size and
eggdimensionswere notably smallerthanthoserecordedon the MeBng fuver.
Of sigrificance is the fnding that meanegg massis alnost doublethat fo! every othe!
speciesdescribedby Tholbjamarson(1996)within the Order Crocodylia.
Nestingsucc^s
The most significant natrual factor affecri.g T. schlegelii egg mortality on the Merang
v.ild pigs (slls tc,'qfa). Five of seven
River appearedto be predatioDby noD-indigenous
nests(717o)&om the 1995nesting seasonon the Merang River had been predatedby
wild pigs. Nests had been pulled open by pigs and eggshellswere strewn around the
site when visited by the suryeyteam. The extent of nest flooding is unl(Ilown and no
flooded nests werc reported by any of the fishennen interviewed. Habitat loss and
modification by fte is probably a significant factor i!flu€lcing the availability of
nesting habitat for T. schlegeliii extelsiYe areasof swamp forest in eastemsumatra
were bumt by human-inducedfires in 1994and 1997.
Hll:rnanpressu"es
The habitat utilis€d by T. schlegelii is also exlensivelyutilised by local people Fishing
and logging are the two pdmary human activities within T schlegelii habitat. Most
river systemsin eastemSumatraare populatedand forest areasadjacentto waterways
are regularly searchedfor fish and hltles. All river systemssurveyedexceptthose in
Berbak National Park (Jambi Province) had been logged at least once and all were
fishedto someextent,including the uppermost,remotecreeks. Tomistomaschlegelii is
widely rccognisedby local people as having little economicvalue and is not usually
detberately capturedor hunted. Local people in most rivcl systemssurveyedwere
familiar with the speciesand consider€dit to be harmlessand shy. Huma!-induced
mofiality of T. schlegelii listed by intervieweeswas incidental drowning of young
individuals caught in fish traps an4 at two rivers in Jambi Province, occasionalegg
coosumption.
Trcdition and local calnre
Thereis a diverserangeofcultures and socio-economicco[ditions at legional and local
scalesin easternSumatra-which would need to be identified for conservationof Z
schlegelii ot specificriver systems.Fo! examPle,in SouthSumata Province, a unique
system of river ownership exists ('lebak lobang'), whereby local heads of villages
gather once a year and bid, on behalf of their village, for exclusive fishing rights to
sectionsofa river or a whole river. At a local scale,fishemen on the Merang River
have pdvate agr€ementsas to where each fisheman may harvest fish, h[tles and
snakei. Suchagreementsvary on n€ighbouringrivels. Tributariesor sectionsof a river
areoften fishedby a farnily, andthe feeling ofcommunal supportis strong.
l9
Other
Information obtainedon the diet, morphometricsand scalation,local beliefs and former
sk)ttade in T. schlegelii is swrunarisedbelow.
Diet. Base.don interviews with former qocodile hunte$ and fishermen, T. schlegelii
has a broad diet and is not a specialist6sh-eater. The most frequendy reported food
items by intervieweeswere monkeys,wild pigs and snakes. Birds, othcr marmals and
reptiles were also listed. StomachconteDtswerc removed from six wild T, schkgelii
(total lengths 66.6-190.0cm) capturedon the Merang fuver and included shrimp and
Pandanus leaves. At least two stomach contents contained numerous nematodes.
Galdikas and Yeager (1984) observeda T. schlegelii predate a Crab-eatingMacaque
(Macacafasciculark) in Tanjung Puting Reserve(Cental Kalimantan Province) and
notedthat the local peoplein the ReserveSaditionally usedmacaquesasbait to catch li
schlegelii. MnlIet (1838) stated the diet of T. schlegelii consistedof fish, monitor
lizatds (Varanusspp.),waterbirdsandmammals.
Molphohetlics. Fiom 1995to 1996,morphometricsand scalationwas r€cordedfrom a
tolal of70 T. schlegelii (55 captive and 15 wild individuals, all from the Merang River
in South SumatraProvince exceptone captive individual fiom the Alai fuver in Jambi
Province) (Bezuijen et ql. l995qb,1996). Snout-venllengthsrangedftom 32.4-188.8
cm. The largest individual measuredw8s a nesting female caphr€d oD thc Merang
River (total length 343.0cm). The largestZ schlegelii sigftd was estimatedto be 4.85.2 m (16-17ft), on the Memng fuver in 1995@ezuijerLet al. 1995b).
Scalation. TwerLtypattemsof precaudalscalationwere recordedfrorn 70 individuals.
Thity-six individuals had a single precaudalpattem ('Type l',Be
ijen et al. 1996),
'Types
and the remaining individuals had
2-20'. Nl T- schlegelii except the single
individual from Jambi Province were from the Merang River, tlus no conclusionscan
be infered as to geographicaldifferencesin morphometics and scalation that may
9XtSt.
Local beliefs. No specific local beliefs were associatedwith T. schlegelii anLongst
interviewees. Somefomrer hrmtersusedchantingand pray€r prior to hunting to ensule
a successfulcrocodilehunt. Specificbeliefs are associatedwith C/ocodyltu porosus.
Historic skin trade. T\e majority of crocodile hunting in easten and souih-eastem
Sumata was in the 1950s-70s. Crocodyhtsporosus skins were ofhigher value than Z
schlegelii shins and all former hunte$ agreed Ih,i C. porosus skins lvere of better
quality. Hrmters sold T. schlegelii sk)nsfor about half the price of C parosr skins.
Tomistomaschlegelii is still widely lecognisedashaving litde commercialvalue andno
evidence of commercial hunting of T. schlegelii was recorded. Specimens are
occasionallycaphuedi! fish traps and sold by fishernen to clocodile farms, who keep
them @izuijen a al. 1996,Webb and JeDkins1991). Cox (1990) notesthat skin tadels
relate the preseuceofosteodermsin the ventral scalesof T. schlegelii as the rgasonfor
its low economic value, although the specieslacks osteoderms(King and Brazaitis
l97l). The large size of the vental scal€s(relative to crocodilo specieswith smaller
ventral scalese.g. C po,"osr.lJ)
may also contibute to the low economicvalue @razaitis
1987).
Conclusions
l. In Sumatr4the largesttemainingpopulationsof T. sehlegelii arein Jambi,Riau and
Souti SumaaaProvinces,wherethe speciesis widely distibuted, althonghplobably
in low densities.
2. The primary threatsto the folagiDg and Destinghabitat of T. schlegelii i east'J!
Sunatra are outight loss of nesting habitat (logging, fue), modificatiou ot
distubance of nestinghabitat (logging, fishing, regular humandsitation of nesting
aleas,motorisedboat activity) and egg predationby wild pigs. The extent of nest
flooding is unloown.
3. RiveN with the highestrecoldeddensitiesof T. schlegelii andwhich are confirmed
to suppolt ble€ding populationsare in Berbak National Park (JarnbiPrcvince) and
the Melang River (SouthSumatraProvince).
4. Berbak Nalioml Pa* is the only prctect€d area in eastem Sumatra which is
curently know! to hold a viable breedingpopulation of I schlegelii. T}re tlor4
fauna aod managEmentroquirementsof Berbak National Palk is well-documonted
(e.g. de Wulf 1982, Giesen 1990, Santiapillai 1989, Silvius et al. 1984) alld a
Aameworkfor maaagementand researchthus exists.
5. Tomistorna schlegelii also occurs in Way Kambas National Palk (Larpung
Province). However, given the widespreaddeforestation,clearanceof river bank
vegetationand inteDsivefishing in the Prcvince, this population is probably small
andisolated.
6. The Merang River is not protected and is currently under a logging co[ces$on'
From 1996to 1998,km 5040 of the dver were logged to within 250 m eith€r side
of the river Qndonesianlaw prohibits loggiog any closet); this is the sectionwhere
the majodty of Z scrleger'i nestswere le-corded.Upon expiry ofthe logging lease'
the IndonesianGoverDrlentrvill decidethe rive!'s future.
7. Prctectiol of someviable breedingpopulatiors on selectedriver systemsmay be the
most effective iuterim and lotrg-tenn method for eusudng the loog-term
cooseryationof the species This stategy would need to incolpoBte upst&am'
fieshwaterforestedareaswith suitablebreedioghabitat.
8. A harvesting program involving T. schlegetii individuds or eggs, and which
provides dire.t financial incentivesfor local peopleto protect foraging and nesting
habitat,may be a! effective lotrg-telm conservahonstrategy.
9. Most areasiohabitdby T. schlegelii re also utilised by humansand aonservation
will only be possiblewith the supportand involvemerf oflocal people,as hasbeen
suggestedfor conaeryationin Danau SentarumNational Park, West Kalimantan
2l
(JeNLeset al. 1995, Jeas€net al. 1995). The socio-economicconditions of local
peopleliviug on a river with a breedingpoplulanonof T. schlegelii would needto be
assessed.
RecommeDdations
10. Conservationof T. schlegelii in Sumata should focus on river systemsin Jarnbi,
Riau and SouthSumatraPrcviuces.
I l. The following st"ategyis lecommendedfor optimal use of conservationfirnds for
the speciesin Swlratra.
. Annual spotlight and rcsting surveys on selectedriver systems. These will
provide baselinedataoDpopulationsize,stucture and fluctuations.
. Formulation of nanagementplans for seleotedrivers which are curendy not
plotected. Manag€mentplans should be specific to eachrivq and describeand
identify: data on distributiorq abundanceand rcsting of I schlegelii',ttrdets to
foraging and nestinghabital; existing socio-economicconditions;local attitudes
towards the species;optimal methods for protection of nesting and foraging
habitat.
. Identification of other river systemswhich suppod breedingpopulations of I
schlegelii,
12.Annual surveysshould be conductedil1 at least one repres€ntativeriver syst€m in
eachofJambi, Riau and SouthSumah"aProvinces. Bas€dou the datacollectedfrom
1994 ta 1996, recoEmeDdedrivers are: Air Hitam Laut River and tributaries in
Berbak National Park (Jambi Province), Teso River @iau Proviqce) and Merang
River (SouthSumata Province).
13.Bas€lin€ suweys should be conduqtedin Way Kambas NatioBal Pa* (Ldrpung
Province)to assessthg statusofthe species.
14.Nesting and foraging habitat for T. schlegelii in Berbak National Park is secure.
Aside fiom annual surveys, no active managementof the speciesis considered
necessaryat this time.
15.It is recorunended that the Merang River be given high priority as a site fo! a
m:nagementplan for T- schlegelii, fot lhe reasonslisted below,
. Baselinedataon densitiesandnestingnow exist ftom 1995and 1996.
. lJntil rccent yeals,the river hasbeensubject€dto relatively low levels ofhuman
disturbance;most oth€r rivers in the region bavebeon extensivelybumt, cleared
or fished.
. Local people on the Merang Rive! are intqested in the speciesand possess
exte$ive lolowledge on T. schlegelii- They have indicated their interestin the
conservationofthe s?eciesandwere involved in field wo* in 1995ard 1996.
. As a result of the project, the Provincial Ministry of Forestry is aware of the
conservatio[ significance of the Merang River for ]1 schlegelii. Prelimilluy
discussionson conservationof the species in the Province were held with
Provincial officials in 1996(Baz'rijenet al. 1996).
. The river is ooe of few remainingin the north-eastr€gion of the Provincevrith
peat swampfolest andwhich supportsa variety ofother thrcatenedfauna.
. A iegional conservationstategy ircorporating atreasnear to the Merang River
hasbeenproduced(seebglow) and a ftamgwork for cotrservationaheadyexists.
16,The intemational importance of th€ mangrovg and swarnp forest ecosystemsof
eastemSumatrahas been recognisedfor many yearc. Regional socio-economic
conditions and land useshave been described(e.g. Danielsenand Verheugt 1990,
GOI-World BaDk 1995). A regional sEateg/ for int€grating conservationand
developmentof forestedcoastalwetlandsin SouthSumata and JambiProvinceshas
recendybeenformulated(Davie and Sumadja 1997,GOI-World Bank 1995)andis
centr€dalormdBeftak National Park. The Senbilang River catchment(eastofthe
Merang River) is proposedfor ptotection as an extensionof Berbak National Park
(Davie and Sumardja1997). The proposed€xtensioncurrently doesnot incorporate
the Merang River. A formal prcposal to National authodties describing the
conservationvalus of the MerangRiver for T, sehlegelii nd proposingthat the river
be incorporatedin this regional strategymay be the optimal method for initiating
conservationofI sciJegelii in Sumatra.
Ack|rowledgments
We are very gBtefirl to thg many people who oontributedto this project from 1994 to
1996. Sponsors(listed in the lntroduction)provided firnding for all project costs. Field
work in 1996 was undertakenjointly by staff ftom WMI and Cental and Provincial
PHPA olfrces in Indonesia. Staff of LIPI identified fish and crustaceans Bumi Raya
Utarna Gloup, CV. SumateraAquaprim4 P.D. Budiman and P.T. Sinar Gunung Mas
Jaya provided enormoushelp. The following p€rsonnelprcvided logistical support,
advice and hformation and were instrumental to the successof the project ln
alphabeticalorder, we give ow sincerestthanks to: B.A. Baker, Dr P. Carmucciari,k
Dwiatno, M. Elliott, Mr Hasan and Joh.Dny,Ir. Hertiarto, R. Kadarisman, h E
Kusmarini, Ir. S. L€gowo, Madari, Mawardi, T. Muk, T. Muladi, Nasrul, Y.R. Noor,
B.I. Ottley, D. Ottway, Ir. R. Paletg h. S, PalggabeaD,Rambi, A, Ruswan,Ruswendi,
A. Sah&, B.K. Simpso4 K. Soemam4 Ir. H.W. Sukotjo, Ir. SuFaltno, Dr A.H.
Tjahav/idjaja Z. Udin, Y. Usman,M. Vardon, S. Wanaputraand Dr D. wowor.
This paper was improved by corments from G. Carr and B. Simpson. Ecology
Australia Pty Ltd plovided lart-funding fot travel costsofM. Bezuijen to atiendthe 14"'
CSG Meeting and logistic support for preparation of this papet. RH. Bezuijen
tnnslated Dutch scientific papers. Finallt we givc our wamest thanks to the fishermen
ofthe AA Hitam Laut, Alai, Benu, Kubu, Merang and Teso Rivers, whose help, interost
and good humour allowed us to work on their rivers successfully.
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Witkamp, H, 1925. Een en anderover Ikokodillen in Koetai. D€ TropischeNatuur, Jaargung
)<IV. Afleveing tr, Buitenzolg.
Wulfde, R. 1982. BerbakGameReserveMamgernentPlan 1982-1987.UNDP/FAO National
ParksDevelognent Project,Field Report38, INS/78/051. Bogo!, Indorcsia.
21
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Tomistoma (Tomistoma schlegelii)at Tasek Berz',
Peninsular Malaysia.
Boyd K. Simpsonr, Alvin Lopez'?,Sharun bin abd Latif
and Alias bin mat Yusoh3
I Wildlife ManagementInternational,PO Box 530
Sanderson,N.T. 0812,Ausualia
2 WetlandsInternational-AsiaPacific,IPSR
UniversityMalaya,50603,KL, Malaysia
3 PERIILnAN,
Jalan Bahagia,28000,Temerloh
PahangDarul Makmur, Malaysia
AbstIact
As part of the management plan for Tasek Bera, Malaysia's first Ramsar site,
spodight sulveys for Tomistoma wele conducted over 12 nights in the
swamp and suuounding rivers. No ctocodiles or "eyeshines" were sighted
in 92.8 km surveyed. Local residents reported commercial hunting of
Tomistoma for skins in the late 1950'sand early 1960's,where all sizes were
taken ard the population greatly reduced. Nests have not been reported in
recent times, although historically they were seen along the barks of the
Bera,Jelai and Tasek Rivers (but not in the swamp itsel0. Sor.e Tomistoma
still occur in the swamp, but are seen infrequently.
The loss and alteration of large tracts of forest habitat due to logging, oilpalm and rubber plantations may have hindered the recovery of
Toflistoma after the hunting period. The area has also seen a large influx of
people living and working in the area over the last 15 -20 years, with
recreational activities becoming popular. Fish poisoning and netting of
some watelways still occur.
Several tributaries of the Pahang River in Peninsular Malyasia reportedly
co\tai\ Tomistomd, ard nests have been reported over the last 5 years.
Tomistoma and C. porosus may occasionally be hunted for meat in these
areas.Extensive surveys are needed in Peninsular Malaysia to confirm and
consolidatethe scatteredreports of this species,which is clearly endangered.
INTRODUCTION
The Malayan False Gharial or Tomistoma (Tomistoma schlegelii) is a large,
slender-snoutedcrocodilian growing up to 5 m in length; it is considered to
be one of the least known of all crocodilians. The Species Survival
Commission of the ruCN has ideniified it as a crocodilian specieswith the
highest pdority for researchand conservation action (Thorbiarnarson 1992).
Histodcally the speciesmay have ranged flom south-easternChina through
to Indonesia. Tomistoma is now thoueht to be confined to Indonesia
(Sumatra, Kalimantan) and Malaysia (Peninsular Malaysia, Sarawak) whele
it is found in the freshwate! upper reachesof rivers and swamps (Sebastian,
1994).The speciesis thought to be extinct in Thailand.
Tomistomais currently listed as 'Data Deficient' in the IUCN Red Data List
(ruCN, 1996),due to the lack of information. Published infolmation on
Tomistomais meagre and scattered throughout the literature. In Peninsular
Malaysia, Tomistoma have only been confirmed frorn a few locations: The
North Selangor Peat Swamp Forest (Butler 1905, Itentice 1990, Sebastian
1994), Pelak River (Boulenger, 1896) and histodcally, the Tasek Bera
Swamp. The Pahang and Setiu River Basins and the Southeast, Jemaluang
and Beriah Swamp Forests are all possible sites where Tomktomamay exist
or areas of unconfirmed reports (Sebastian, 1993). Tofiistom4 ale now
legally plotected throughout Malaysia but there have been no systematic
crocodile surveys carried out in the Peninsula.
Tomistoma surveys were undertaken at Tasek Ber4 by Wildlife
Management International (WMI) under the auspices of the ruCN
Crocodile Specialist Group. These surveys were conducted in conjunction
with The Tasek Bera Proiect and had the following objectives:
. Assesscrocodilian speciespresence;histodcally and currently.
. Assessthe status of species:their historical distibution and abundance
(in relation to habitat types) relative to their cullent distribution and
abundance.
. Determine habitat conservation priorities for Tomistomaand identify
cuEent or potential threats.
. Collect information on breeding status and reproductive biology if
possible
The Tasek Bera Proiect
The Tasek Bera Proiect involves the development and implementation of a
management plan for Malaysia's first Ramsa! site: the freshwater swamp
ecosysiem at Tasek Bera (Lake Bera). The proiect is being developed @
Wetlands International - Asia Pacific (WIAP) in coniunction with the
Institute of Advanced Studies (IPT) of the University of Malaya, and aims to
integrate wetland conservation, reqeation and ecotourism. The initiative
will be carried out with the PahangStateGovernment and involves the
indigenouspeopleof the aleal the Semelai.
Duling the initial stages of the project, numerous flora, fauna and
hydrology sulveys were being conductedto provide information for the
developmentof the managementplan. The core zone of the Ramsa! site
covers 26,000hectaresand includes the lake, surrounding swamp and
lowland forests.A furthe! 22500hectaresis a buffer zone compdsingpart of
the catchment a!ea.
Study Area
Tasek Bela is a large alluvial peatswamp forest situated apploximately 100
km east of Kuala Lumpur in central Peninsular Malaysia (Fig. 1). It consists
of a dendritic complex of meandering tracts of swamp folest some 35 km
long by 25 km at its widest point, though each arrn of swamp may only be a
kilometre or two wide. The swamp covers over 60 square kilometres
between areas of raised lowland forest. Water flows into the swamp
throughout the year and it dlains northward through a single confluence,
into the Tasek River, which in tuIn drains into the Jelai and Bera Rivers.
Duling the dry seasonwate! is lestlicted to a single naFow channel which
flows through the healt of the swamp folest. The wate! is usually less than
1.5 m deep at this time of the year, but the channel is intersPersed with
many deep, wide pools or lubuks. Channel width is usually between 3-7 m,
but widens into an open lake at the northern end of the swamp uuhich is
approximately 3.5 km long by 500 m wide.
The most common habitat, which occupies two thirds of the swamp, is
peatswamp forest, composed of Eugenin trees with Thoracostachyum sedge
fringing the waterways and forming an understorey. This forest type
dominates the dendritic arms and waterways of the southem swamp. The
northem reaches are dominated W Panda us clumps and Lepironia tePJd
beds which make up the remaining thild of the swamp errea.This habitat
fringes the open lake which is dotted with mar.y Pa danus islands.
The wetlands of Tasek Bela are surrounded by dry lowland Dipterocalp
forests, characte sedby Dipterccarpus a\d Shorea tlees. Most of this folest
has at some time been logged, cleared or altered, and very litde (if any)
primary folest lemains. Large kacts of this forest have been cleared under
the government's Federal Land Development Authority (FELDA) scheme,
which develops and allocateslarge oil-palm and rubber plantations to new
settlers.Such schemes have resulted in the isolation and enclosure of the
wetland of Tasek Be!a, leaving only a small strip of dry lowland forest of
aboutlo 000 ha, surrounding the swamp.
METHODS
All fieldwork at TasekBerawas carriedout ove! 2 weeks(26June - 11 July
1997)using local guidesand boat drivers.
Sutveys
Surveyswere undertakenat night ftom a 4.2m fibreglassboat,Poweredby a
15 IIP Yamahaoutboardmotor. In some survey units, the moto! was not
used and the boat was paddled. Spotlighting proceduresfollowed that
'DolPhin' torch
outlined by Messelet. aI. Q987).A 12 V spotlight or a 6 V
wele used, dependingon the width of the stream being sulveyed. Fou!
m), were surveyed by foot
naqow water holes,of varying lengths (100-400
ftom the banks,using torches
Interviews
Interviews with local residentswere carried out to assesslocal knowledge
on various aspectsof TomistomQ.Most interviews were conductedin and
around the 14 villagesof TasekBera(Fig 2) and the maiority of interviewees
were known to have had dealingswith Tomistoma at some time. Most of
the peopleresiding at the swamp had lived in the area all their lives and
were only familiar with the TasekBeraregion.
A standaldisedquestionnaire(Bezuijen et al. 195b) covered current and
historicalprospectiveson: speciesplesence,distribution,abundance,nesting
'Recent sightings' of
biology.hunting and trade, and other information.
Tomistomawere classifiedas thosewhich had occurredin the last five years
(ie trom 1993-1997).AU pre1993 sightings are referred to as 'Historical
Sightings'.As Tomistoma sightingsare quite well known throughout the
community, 'Recentsightings'of the Tomistoma also include secondhand
information: that is, reports made by the interviewee who knew of
someoneelse who had seena Tomistoma.
Mapping
Broad scale habitai t}?e was recorded for vegetation adiacent to the
navigablechannelrunning south-northin the Tasek BeraswamP.Channel
depth was measuled and width estimatedvisually every 2-3 km. DeePer
waterholes, or lubuks, were recorded with the aid of a Garmin GI'S 40
Global PositioningSystem.Lubuk depthswere rneasuredusing a weighted
cord with 1 m graduations.Localnamesfo! the lubuks wete recordedand
the width and length estimated.Water temperatureand pH were measured
in a number of locationsthloughout the swamP.
35
RESULTS
Surveys
All navigable waterwayswithin the swamp, from the JelawatBridge to
Pathir village, were surveyedtwice over 8 nights (57.4km). A further four
waterholes,the Tasek and part of the Jelai and Bera Rivers were also
surveyed (35.4km) over 4 nights. No crocodilesor eyeshines \ /ere sighted
during any of the spotlight surveys(Simpsonet al. 799VInterviews
A total of 19peoplewere formally intelviewed from 8 villages (or areas)in
TasekBeraand the surroundingregion (Simpsone, al, 199n. A\ additional
number of people frorn the villagers of Kuin, Benal and Bukit Gegerish
reported that their village had no infolmatio\ o\ Tomistoma. Most of
thosequestionedhad spenttheir entire lives at TasekBeraor in the region.
RecentSiehtines
Twelve reports of Tomistoma were lecorded within Tasek Bera and
associatedrivers to the North ove! the last five years(Fig. 2). Sightingshave
occulled thloughout the swamp from Jelawatvillage in the South, to the
BeraRiver in the North. Most Tomistoma were seenin the deeperwaters
of the lubuks, and where the sizewas known, they were estimatedat greater
than 3 m long. Largeindividuals were said to dive immediately on being
seen.One exceptionwas a small individual (< 1 m long) seenbaskingon a
log. Usually 3-4 sightingsof Tomistoma are reported from the Tasek Bera
regioneachyear.
HistoricalSightings
Sightingsof Tomistoma plior to 1993were repolted by 16 of the 19 people
questioned,with nine of these people being involved in some form of
hunting. Of the people interyiewed who were over 50 years of age, most
had been directly involved in hunting o! had personally see\ Toflistoma
in the Tasek Bera region during that period. Some interviewees reported
seeing "many" Tomistoma in the 1950'sand early 1960's,with all size
animalsbeing reported(hatchlingsto animals6 m long).
The greatestnumber of reportscamefrom the Tasek,Jelaiand BeraRivels
directly to the Nolth of the TasekBeraswamp (Fig.2). "Many" Tomistoma
were seen along these rivers, and were reportedly found all along the Bera
River from the TasekBeraswamp to the confluencewith the PahangRiver,
a distanceof approximately50 km. Within the swamp itselt the majority of
sightin-gsoccurredin the nolthetn half, from Benalvillage to Pathir village
Saltwater Crocodiles, Crocodylus polosusl were also reported flom the
Tasek Bera area, mostly in the 1930'sand 1940's.Only two old hunters had
see^ C. porosus in the region. Most reports came ftom sightings made by
the parents or grandparents of intelviewees. Saltwater crocodiles have not
been reported in the region since the 1950's.
Nesting
Thele were no historical rcpofts of Tomiston a nesting within the swamP
itself. All historical nests leported were found outside the Tasek Bera
Swamp, on the banks of the Tasek, Jelai and Bera Rivers. Numelous nests
were sighted prior to the 1960's, but reports since have been sporadic.
Nesting was said to occur all along the Bera River, on the banks of the dry
lowland/secondary forest. Of those interviewed (n=19) the latest sighting
was of an old flattened nest in 1980,in Lubuk Perah, off the Tasek River.
Nest and egg descriptionswere similar to previously published repolts flom
-1997,
Ladr^g and Stuebing 1997).
other regions (Bezuijen et aI. 7995b;
Interviewees reported nests to be composedof leaves and small twigs raked
into a mound, 30-60cm high and about 1 m in diameter. Clutch sizes were
reported as 15 - 30 eggs,each approximately 10 cm long. Nests were rePorted
to occur in the dry season,from June to August. Femalesdid not defend the
nest which was usually within 20 m of the river. Wallows or deplessions
beside the nest were not reported.
Diet
Tomistoma was reported to eat a valiety of Prey items, including fish,
mouse deer, dogs, pigs, snakes, monkeys and stones. One old hunter
reported that all Tomistoma caught greater than 15" in circumference
lapproximately 1.2 m longl had stonesin their stomach.
Hunting and Trade
Tomistotnawere commercially hunted for their skins over a 3-4 year Period
from approximately 7958-1962.Hunting occurred in the Jelai, Tasek, Bera
and Serting Rivers (north of Tasek Bera), as well as the northern readtes of
the swamp, from Benal village to Pathir village (Fig 2). ftom those
interviewed, it was estimated that up to 750 Tomistoma may have been
taken from the Tasek Bera Swamp and the surrounding rivels during lhis
period. Tomistofi4 may have also been taken by hunters who were not
canvassedin these intewiews.
The majority of Tomistomawere repodedly caught using a Pointed sti& 30
cm loqg which was baited, usually with fish or pig, and attached to a length
of dried lattan vine. The bait was set 15-30cm above the wate! edge. After
the crocodile had swallowed the bait and swam off, the floating vine could
be tracked dowa and the crocodile pulled to the surface with the pointed
stick lodged in it's stomach. This method usually caught crocodiles larger
than 1.5 m long. Teams of 2-4 professional crocodile hunters used this
method and worked during the dry season. Hunters mostly worked the
Tasek, Jelai, Bera and Serting Rivers and did very litde hunting in &e Tasek
Bera-swamp itselt whele the Tomistomanumbers were too low to produce
gooq retutns.
Villagers also catght Tomistoma on an opportunistic basis, catching them
by hand, in fishing nets or spealing them. Most of the opportunistic catches
occurred within the Tasek Bera swamp and continued infrequently afte!
commercial hunting had ceased.
Tomistoma of all sizes, flom hatchlings to 6 m animals were caught, killed
and sold. Animals greater than 1.2 m had the belly skin takerL while
smaller animals were sold whole or as holnback skins. Most of the
Tomistomacaught came from the Tasek, Jelai and Bera Rivers to the North.
Within the swamp ploper/ the number of crocodiles caught during the
huntinS period from 1958-1962was estimated at 2G30. By the end of 1962,
Tomistomanumbers were greatly dirninished (in all size classes)and prices
were low, blinging an end to sedous hunting in the Tasek Bera area.
Skin prices varied durirg the period of hunting, but generally the plice for a
belly skin was RM2.00-3.50/inchAfter the main hunting period, the price in
the mid-1960's increased to apploximately RM5.00/inch. Smaller crocodiles
up to one metre in length could be sold whole, and would bring prices of
around RM15.00.
A Tomistomaskull was inspected at Papak village which had been obtained
from a fishelman about 20 years ago. The skull was 61.0 qn long (Head
I€ngth), which, using regression equations derived by Bezuiie\ et al. (7995a,
b), equates to a Tomistomawith a total length of about 3.76 m (124).
Tasek Bera Swamp
The navigable swamp channel within Tasek Eera measures approximately
20 kms from the Jelawat bridge to Pathir village. Channel width is usually
between 3-7 m, with the depth usually less than 1.5 m. The wate! level at
Tasek Bera during the field tlip (26 June - 77 Jrlly 7997) - the dry season, was
quite low. The standard water depth scale at the Tangung Kuin Jetty (Fig. 2)
measured apploximately 80 cm for the duration of depth measurements.
The water level did rise to 110 cm with rainfall in the alea during the last 45 days of the trip.
There are 38 deep waterholes, or lubuks, which intersperse the dry season
channel from the Jelawat Bridge to Pathir village (Simpson et at. 1997).
Nine of these ale !n the open water of the northern swamp. Most of the
38
lubuks in southern part of the swamp, from the Jelawat bridge to Benal
village usually measured less than 3 m deep. Those lubuks from Benal
village north to PatN! village were usually 46 m deeP.Lubuk sizes varied
but were usually 100-300m long, although some measured only 20 -30 m;
lubuk width was between 20-100m.
Water temperature was lower in the faster flowing areasof shallow channel
(26 C) than in the deeper lubuks (27.5- 28.5 C). Water pH was the same
throughout the swamp (5.5).
DISCUSSION
Tasek Bera
The population of Tomistomaat Tasek Bela and in the Tasek,Jelai and Bera
Rivers has been clearly reduced over the last 40 years, and only a few
individuals may remain. The commercial hunting of all sDes of
Tomistoma for the skin market was the most obvious reason. It aPPeals
hundreds rather than thousands of Tonistome may have been removed
from the region during that peliod (i958-1962),but such losses Probably
represented a large proportion of the population. Very few animals
remained after the commercial hunting had finished in 1962.The sPeciesis
now legally protected and in coniunction with very low densities, is not the
subject of deliberate hunting in the area.
The loss or alteration of the natulal habitat throughout the area is a factor
which threatens the recovery of Tomistoma populations. The remaining
dry lowland forest at Tasek Bera has been subjected to varying degrees of
clearing and alteration. Forest has been logged to varying degrees, and
subjected to shifting swidden agricultule. The large oil-palm and rubber
plantations of the and Federal Land DeveloPment Autho ty (FELDA)
schemes further isolate the swamp. These schemes result in la!8e tracts of
forest being cleared for agriculture and 8leatly increase the Potential fo!
feltiliser run off whidr can impact on the swamP in many ways.
The increasing number of peoPle to the a!ea, through toudsm and FELDA
schemes, may also impact o\ the Tomistoma's ability to !ecove!. An
inclease in the numbe! of powered recreational and fishing boats on the
ver cruises
Bera River has occuded ove! the past few yeats, with
in$easing in popularity. The increase in human activity since the main
FELDA settlements in 1983 has also resulted in an increase in fishing
intensity, especially netting and poisoning of ttle Bera Rive!. These fishing
activities are leal threats to Tomistomaand the aquatic fauna generally. The
use of tladitional loot poisons (which have a limited effective range) have
been o;vershadowed in recent times by the use of Pesticide Poisons and
cyanidqbased industlial chemicals. Such chemicals indiscriminately kill
and affect all aquatic life forms. Fish netting occurs frequendy along the
Bera Rive!, with large nets stretched acoss the rive! width. These catch all
sizesof fish, restrict the movement of Tomistoma, result in individuals
drownin& and may decreasefood availability.
No Tomistoma wele seen duling the surveys, but information from
villagels indicated that some individuals are still present in Tasek Bera.
Thesehave beeninfrequentlysightedove! the past severalyears,with most
reporting largeanimals greate!than 3 m long. It is probablethat there ale
only a few individuals which are seenas they move within the swamp. The
report of a smatI Tomistoma may suggestsuccessfulnesting somewherein
the legion, within the last 5 yealsor so. It is possiblethat breedingstill takes
place,although clearly infrequently. All previous nesting lepolts indicate
that the lowland forest of the Tasek,Jelai and Bera Rivels provide suitable
nesting habitat for Tomistoma, although no nests have been reported in
nearly20 years.
PeninsularMalaysia
Information obtained dudng the Tasek Bera surveys indicate that
Tomistoma can still be found in t butalies of the Pahane River. The
Departmentof Wildlife and National Parks (PERHILITAN) at Temerloh
have four Tomistoma in their minizoo. One was confiscatedflom a
fishermen in 1995 from the Jengka Rive! (Fig. 3). The 3 others were
obtained since July 7997.Two small individuals came from Tasek Chini,
while the other from anothertlibutary of the PahangRiver (Fig,3).
lnformation from Menchupu village (nea! the RasauRiver) indicatesthat
all sizesof Tomistoma(aswell as C. pmosudare frequently seenat night in
the Rasau,l€par and PahangRivers (Fig.3).The Luit and Rompin Rivers
were also said to hold populations of Tomistoma. Batin Kandol of
Menchupu reportedseeingTomistoma nestsduring the dry seasonon the
banksof the Rasauand Lepar Rivels 4-5 yearsago.A 40 kg [estimatedat 2.4
m longl Tomistomc was caught in a net in 1996.The lower jaw was
examined and the dentition noted as 4/15 (Simpson et al 7997), in
accordancewith other descibed Tomistoma specimensOordansky 1973,
Bezuiienef al. 1995a).Tomistoma caughtasincidental catchin fishing nets
in the RasauRiver areacan still be reportedlysold for RMs/kg, but during
the Chinesefestive seasonpricescan reach RM40,/kg:Tomistona (a d C,
porosus)are sometimeshunted at this time.
The Tomistoma surveys at Tasek Bera were the filst such surveys to be
carried out in Peninsula!Malaysiaalthough Tomistoma have beenknown
fiom the Peninsulafo! more than 100years.Histolically leported from the
Perak,Pehangand SelangorRivers (Fig. 3) (Boulenger1896,Butler 1905),
Tomistomahave only been recordedfrom the North SelangorPeatSwamp
Forestln lecent times (Prentice1990,Sebastian1993).As the curtent status
and digtribution of Tonistoma within Peninsular Malaysia is unknown,
comprehensivesurveysare urgently needed.Tomistomo
may still be under
somehunting pressurein someareas.
40
ACKNOWLEDGMENTS
This field trip was jointly undertaken by staff of Wildlife Management
International, Wetlands International-Asia Pacific and the Malaysian
Department of Wildlife and National Parks. Clawford Prentice and his staff
from the Tasek Bera Project in Temerloh provided enormous helP.
Teacherhousing was provided at the Pos Iskander school while we worked
in the area. Our sincerestthanks goes to Stam, our boat driver, and his
family who allowed us to'take over'their house at Pathir village. Mr
Rapiah bin Muda and the staff at the Temerloh PERHIIJTAN minizoo
allowed us to catch and measure their Tofiistoma .
Funding was provided by the Asian Conselvation and Sustainable Use
Group (ACSUG), Wetlands International-Asia Pacific (WIAP) and the
Crocodile SpecialistGroup, through a donation flom the Chicago Zoological
Society.
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Tomistoma.Reporl on the MalayanFalseGharial ('fomistoma schlegelii)
Malaysia.
at TasekBera,Peninsular
Thorbjarnarson,
J.B.1992.Crocodiles.An Action Plan fo! their
Conselvation.ruCN, Gland, Switzerland.
o
northernrivers
Figurel. TasekBeraSwampand associated
Eera RjverBridge
ranjun
Kuin
e
*
.c
\Q
\E.
\"s
_lT
IJ
Village
Recentsightings(1993-97)
o Historicalsightjngs(pre-1993)
Figure2. Sightingsof Tomistomaand associatedvillagesat TasekBera
44
THAILAND
MALAYSIA
KualaLumpur
Key
l. PahangRiver
2. JengkaRiver
3. Luit River
-
SINGAPORE
5. RasauRiver
6. RompinRiver
8- Tasek B€ra Sw?mp
9. North SelangorSwampForest
tO. Tasek Chini
Figure
3.
Areasin Peninsular
Malaysia
with reported
sightingsof Tomistoma
45
Preli.dinary
charles
surveyg
of
Palugtrine
A. Ross1, Jack H. cox2, Hellen
iD KaliDanta!
crocodile6
Kurniati3
and scott
Fraziera
t
a
g s s r o r e n l,ane, DuDl<irk, MD 20754 USA
Nc 28211 usA
2919 Colony Road, challotte,
" Ferpeloloqy
'ral.an Raya
Bogoriense,
Diwision,
Museun zoologicun
,lakarta-Bogor
Km 45, C i b i n o n g 1 6 9 1 1 , l l e s r J a v a , I n d o n e s i a
l'letfands hternational,
P.o. Box ?002, 57oo cA WageningeE, The NeEherlands
Abstsrac!
crocodif ians rePorxedl y occur in
Thr'ee species af pafusErine
(Indonesian
an apparent
raninus,
Kalimanxan
Botneo) : Crocodyfus
A fourth
Bozrtean endemic, C. siamensis,
and Tomistona schlegelii.
river
systefis, but is
specjes, C. porosus, afeo inhabits
freshwater
and
was
aox a focus
more connoalfy known from caastaf
habitatg,
j.rl
are
C.
siamensis
stoma
schlegelji
a,'ld
specjes
chis sLudy. Torni
by
theactian
priority
fot
conservation
considered
highest
species
(CSG).
recenx
evidence
The
most
IUCN/SSC Crocadile
Speciafist
Gtoup
of c. raninus is a juveni]e
specimen coTTected ca. 7878.
1995 and 7996 as
were conducted
in twa phases during
surveys
(SI) -Indonesian
Institute
part of a joirt
Inexitution
Snith;anian
(LIPI)
elere to
I4ain objectives
af Sciences
z:esearch project.
in xhe
and oceurrence
dacument an exxant popufation
of C. raninus
gpecimen seties
for taxonomjc
wifd of C. siamensis,'
and xo obtain
and data on
study.
ar?d c. porosus/
Specimens of T. schlegelii
were
of a7l fout crocadifians,
distribution,
ha.bitat
ajad nesting
of popltl-ation
baeis.
At evafuaxion
coTTected on an opportunistic
status vas nat a project
objective.
In f995 a wifd popuTaxion of c. siamensis was contitmed in xhe
of a
Two individuafs
Mahakam River
system
of East
KaJ-imanxan.
in
South
group
an a farn
raninus
ctoeadife
were
examined
Phase 2 1n 7996
Rafimanxan,
and Xigsue obtained
fram
one.
riwer
in xhe Arat
and JeLai
emphaslzed
eearches
for C- ranious
area edrere the raninus
sysXems of CenXraf Kafima'lXalj.,
the general
grodp individuafe
but yieTded no ewidence
were said ta originate,
specimens of
additionai
af the epecies.
Mahakam surveys produced
nests, one
c. siamensis and inspections
of xwo active T. schleqelii
with
Three nests
vegetatiat.
on land and xhe oxher on ffoating
to T. schlegelii.
spoiTed cTutches were aTso atttibuted
Nidhf ..trnfa
in pl pvct fakes and riwers
of West and Centraf
by fTooding
comprornised
Kafimantan
taxaljng
199 km were Likely
(d=o.oJ/krt).
T.
a juwenife
was fron
recorded
The anTy eyeshine
eighx T
In East l<afimantan,
schlegelii
and an aserlj.nedC. porosus.
Rantau
juveniTes
Kedang
frofi
Sungai
were tecorded
schlegelii
(d=0.11/kn).
encountered at
were frequentTy
captive
T. schlegetii
(80 individuais
and iE obviousfy
at 20 sites),
the viTTage l"e;ef
of Kafimantan.
crocadifian
the corfuon pafustrine
critical
to compEise
sixes
apptaised
wetfand
are described
pafustrine
in Kal"inantan
crocodiLiaiA
f^?
F^n)1
^r^ra^r;
^n
46
for
habitat
and recon'nended
IatroducCion
for
(Map 1) is
interest
of
special
a region
Kalimantan
Ct:ocodyius
Four
species:
management.
researcl
al1d
crocodilian
have
c
ren;ntiF . a. Fiamensie ar\d Tomistoma schfegeLij
-been
The
region.
Asia-Pacific
area
in
the
recorded, the most of any
highin
(C.
ar'd
T.
EchLegelii)
siamensis
presence of two species
to the IUCIi/ssC Actlon
prlority
surveys according
need of status
litt1e
(Thorbjarnarson
1992)
i,tan fo-r crocodifians
, and a third
(Ross
to
and
cox)
authors
1ed
two
of
the
C. raninus,
known species,
and
of
biological
suite
proposala
addressing
formulale
a research
problems.
conservation
were: 1) to document or
The main objectives
of the ptoject
confirm the occulrence
population
rani'lus
and
C.
disprove an extant
series of whole
specimen
2)
obtain
wild
csiamensis;
and
in Ehe
of
gamples
specimens
study.
for
taxonomic
and
tissue
animals,
skulls
habiEat
d
i
s
t
r
j
b
u
t
i
o
n
,
p
o
r
o
s
u
l
,
d
a
t
a
o
n
c
.
a
n
d
s
c
h
i
e
g
e
f
i
j
a
n
d
of Tcrocodil'ians
all
four
of
ecological
aspects
nesting'
and
other
and
basis, Asse6einent of population
on an opportunistic
were collecLed
sEacus was oucside Ehe scope of this study.
smithsonian
the
through
by
Ross
money obtained
Grant
to the ReEearch
to be submitted
Institution
allowed the proposil
(Puslitbang),
of the
a division
and Developnent centre for Biology
vrith
discussions
After
of Sciences
fodonesian
Institute
{LIPI) .
was revised to
officials.
the proposed project
LlPr and Puslitbang
of surveys to two
by expandj.ng
fieldwork
facilitate
-approved.the duration
of field
the
start
Prior
to
phases,
and
was
seasons or
on
join
co-inprenenlor
project
as
a
the
Kurniati
agireed
to
work,
(MzB),
arrangements
and
Bogor
],IPI
and
Museum
zoologicun
behalf of
in
wiEh the CITES Managerdent Authority
were made for collaboration
Nature
and
Protection
of
Forest
Directorate
GeDeraf
lndonesia:
the
(PHPA) , Ministry
of Forestry.
conservation
involved
aspects of the research
one of the most intriguing
to
Conmonly referred
oi C. taninus.
attempts to document survivllas a
described
the species was initially
as th-e Borneo crocodile,
(= crocodylus
cuvier
biporcatus
pa-Iustrlne
variant
of Crocodilus
obtained
of a skull
Schneider
1801) from the type series
lorosus
preserved
(=Barito)
and a juvenile
River in ie:e,
trom the Banjer
from the
collected
betneen l-836 and 1844 by Diard
in atcohol,
The
(Mliller and schlegel
1844).
Pontianak area of west 1(alihantan
Museuan,
scries
is denosited
at the Nationaal
Natuurhistorisch
ta C. raninus
specimens attributed
Tvro additional
l,eiden (RMNH)i
fron "Borneo" in the American
are known. One is a skull ostensibly
an
(AMNH). The other
is
New Yotk
History,
Museum of Natural
at
the
juvenile
by w.T. Hornaday, and is housed
collected
alcoholic
The only
Harvard Universixy
\l4cz).
zoolory,
Museum of domparative
specimen is "Borneo, Hornaday",
wilh the juwenile
d.ata associaGd
collecting
by him in 1878 while
collelted
was like1y
but lt
orangutdns j-n southern Sara\,/ak (see Hornaday, 1885) .
the
Dedpite
reigned
regarding
long
confusion
of museurn specimens,
existence
palustrine
of this
identity
the unequivocal
skulls
fnclusion
of one C. potasus atld two C. sialnetsjs
crocodile.
among Mriller and Schfegel's
s1mt14)ica1 series of five specimens was
by
was resolved
li
a992 the confusion
the principaf
reason.
from Pontianak as the I'ectotl'pe
desj"gnation of the Diard juvenile
to
In addition
at c. raainus Muller and schlegel 1844(Ross 1992).
a
skull
morphology,
squaination vras amended to include
distinctive
group
scale"
pattern
ventral
that places the species in a "large
The taxon was
122-2'7 tra.Lsverse rows) of crocodifians
liden 1992).
date
no attempt
valid
species,
and
to
as
a
therefore
"resurrected't
its status.
has been nade to refute
aethodE
series of specimens for taxonomic research were aesembled from
T.
l4osE juvenile
animals whose origiin was considered indisputable.
cag'es at
fron holding
and c. siamer1sjs were obtained
schTegefii
habitat.
viltages
of crocodile
and huts in the imnediate vicinity
on a night
Tomisxofia \iras hand captured
One specinen,
a juvenile
from rarrch
was obtained
C. sjametrsj,g material
survey. Additional
from the Mahakam River system,
stock in Balikpapan
that. originated
were pithed and preserved in
collected
individuals
East Kalimantan.
15* formalin,
then transferred
Eo MZB, where the preservative
Tomistoma Echfegel-ij
with
75? ethanol.
solution
was replaced
by Iocal
residents.
where made available
skulls
were collected
in river
systenrs
Distribulion
records
were accepted for species
were observed,
and where wild
where captive
individuals
or skulls
individuals
were sighted or captured.
of
were conducted with owners, managers and staff
Interviews
persons
professingi
most crocodile
farns
in Kalj.rnantan, and with
level . At captive
knowledge of crocodiles
at the town and viflage
numbers of
wa6 sought on species present,
locations
informati-on
A
separate
actiwity.
origin,
and breeding
6tock,
ag.e groups,
where
1eveI,
procedure
the village
waE foIlo!,/ed
at
standard
present,
questions
were asked regardjng
Ehe nufiiber of species
abundance,
and current
by habitat
t]tpe, historical
discribution
patterns,
During Phase 2
and nesting biology/ecology.
exploitat.ion
showinq neck and body
a laninated
sheet of Crocodyfus photographs
assist
species
names was used to
squamation
without
written
names.
local
of species by informants
citing
identj.ficat.ion
primarily
documenc species
!o
Night
counts,
conducted
A
methodologY.
follorated
standard
occurrence and obtain speclmens,
lakes
and
projected
surface
of
afong
the
bright
was
beam of tight
indentions
care taken to cover shoreline
waterways, with partj-cu1ar
'cu1-de-sacs'.
warious
bow
of
from
the
observer
scanned
and
The
motors,
outboard
40
h.p.
with
vessels:
speedboats
equipped
longrshaft
(narrow
powered
shalLow
by
wooden
vessels
ketintings
from small boats and p?ddl-ed
propelleis)
and, less frequently,
calculating
maps precluded
of
targe
scale
iarnpans.
Unavailabitity
Kalinantan'
West
particularly
in
preaise distances
of some surveys,
from liwe animals by direct
data was collected
Morphometric
In addj'tion,
squamation.
length and ventral
neasurem'ent of total
dorsal
to
record
and Sony Hi-8 mm video \dere used
35 nm fihn
lateral
and ventraf
scale patterns.
Clutch
a trip-Le beam balance and vernier caliper6,
and 0.2 mm respectively.
data were recorded
accurale Eo within
wlth
I gr
(GPS) coordinaLes
were taken for
Gfobal Positioning
Systen
survey
nest
sites,
were conducted,
villages
where intervievrs
of
points.
Coordinates
eyeshine/capture
!4ral4)oints and crocodile
speedboat
assist
recorded
to
map points
!.tere also
important
syslems.
wia the sea between river
when tsravelling
navigation
Regul.tsE aud discuE8ion
frorj. 20
was conducted
in
Kalimantan
Phase 1 fieldwork
in
farms
Most
crocodile
13
Deeember
1995.
september
through
present
to
collect
and
for
species
were
exanined
Kal-imantan
origj-n of stock
data.
Information
on the purporced
morphological
selected river
plan
Phase
2
of
intensive
surveys
i!1
was used to
for
journeys
to village
undertaken
were
As
time
a1lowed,
river
systems.
and EasL
west,
Central
in
the
interior
of
facilities
holding
data on
specimens and additional
Kalimantan provi.nces to collect
niqht counts and
rn conjunction
with these excursions,
occlrrrence.
were conducted in lakes and rivers
daytime assessment of habitat
were said to persist.
where crocodiliarls
co 21
17 July
fron
out
were carried
Phase 2 activities
for
by Frazier
The research
team was joined
septemler
.1996.
1
Phase
of
the
basis
west
Kalimantan.
On
with
KurDiati
in
surveys
Arut
in
the
taninus
priority
given
for
C.
was
to
searches
results,
river
systens of Central Kalj-mantan and the Kapuas River
and.telai
of c. siamensis
in
west
Kafimantan.
Continued investigation
system
out by
Mahakam River of East Kalimantan was carried
i; the central
of a
documenE the occurrence
counterparLs
Eo fully
cox and focal
aod to collect
data or1 basic breeding biology
breeding population,
including
Incidental
observations
on T. schfegeTii,
and ecology.
funds
were rnade as time and lj-mited
nesting
biology
and ecofogy,
permitted.
Species
ctocodyLu'
aceounts
siafrea'ig
recently
distribution
of c. siame''sis was untif
Historical
of
countries
Asian
mainland
Southeast
considered
to
be the
from
cambodia and vietnam (Groombridge 1982), but skulls
Thailand,
.lava (Ross, 1992; Ross et a-I. 1995) suggest that the range extended
as
1992 C. sjamensis was reported
Until
at least
to that island.
extant popufation
but a substantial
in the wild,
virtuafly
extinet
(several thousand?) is now kno\tn from Cambodia, refimants of ca 100
in
in vietnam and Lao DPR, as do a few individuals
each persisc
Thailand (Ro66, 1998).
Ii 1990, an unusual 2 m captiwe crocodyTus was photographed
(Frazier
East Kalimantan
at Muara Ancalong in the t'tahakam River,
was
data
squamation
ventral
1990) . Although
and Matirrbongs
with
c'
consisteot
were
characters
the
dorsal
unawailable,
49
juvenile
C. siamensis were docunented
siaJnensis - T\ro years later,
acquired as smaff
vTere
reportedly
and
on farms in Easi Kalimantan,
(cox
juveniles
1993).
et
a-2.
Mahakam
from the central
dala were recorded
During Phase 1, morphological
Morpbology.
fron
the Mahakam River
from 42 captive
specimens that originated
Surya Raya,
at
C.v.
stock
\4tere farm
Most of these
systen.
(sevet!
juver1iles
examined)
which
were
of
but nine were
Balikpapan,
and
deduced
Mahakan,
central
in the
holding facilitj-es
from wiilage
more
breeding
possibfy
or
three
from at least two,
to be offspring
from 28 captive
data was obtained
Fufl
squanation
crocodileJ.
were taken from
scute
clippings
Tai,l
using Hi8 video.
individuals
aduLt c.
five
group
An
additional
DNA studies.
for
che same
v/ere
(from
individuals)
ca.
15
stock
of
totat
siamersis
near:
farm
nh-rddra.had
^i
P 'T'
Al as
Watu
Utama crocodile
is
less
animal-s
of
these
origin
South
Kalinantan.
Banjarbaru,
Kalinantan.
to be Central
certain,
but purported
Table
1.
sample
eomparison of mainland Southeast Asj-an and
Morphometric
include
c.
siamensis - Measulements
EasL Kalimantan
(range,n).
ftonr
are
Mainland
data
deviation
astandard
R o s s (1 9 9 0) .
Transwerse ventral
scale rows
Mainland
SE Asia
(29-33,n=14)
East
Kalimanta1l
32 -7 lL.23
(30-35, n=35)
Transverse throat
scale rows
50.3 11.49
f 4q-q?
ur -,
Basal
'i rradrrl
caudal
.Yi
i-1r
y e s ( n = 1 5)
n=1 ql
i 4 7 - 5 5 ,"t.r,
n=35)
y e s ( n = 35 )
In the East Kafimantan sample, the nu$lcer of cransverse throat
the highest nunicer of in
scale rows, of which c. siame.asjs exhibits
rows,
ventlaf
scale
transverse
and the number of
Crocadylus,
to those from
tlpical
of "small scale" Crocodyfus were very similar
in
mainland individuals
sarnpled by Ross (1990) . Small differences
in sample
due mainly to variation
the two data set6 are piobably
frord lthi-ch ventral
At1 35 individuats
fron East Kalimantan
size.
as
irregularity
caudal
data vrere recorded
showed median basal
(1973) .
reported by Brazaitis
buE few of
No c. siamel?srs sku11s were examined in Kalimantan,
showed the extrene
individuals
and adult
captive
the sub-aduft
in
ani.nals
of mainland
characteristic
raised
squamosal ridges
altd many did not clearly
Thailand ;nd Vietnam iRoss, pers. obs.),
These
ridges '
of
these
coloration
unigue
light
exhibj-t
the
study
and further
influeoced,
a-re ontogenetically
characteristics
any, of these
if
the importance,
before
assessing
is required
(Ross 1996) .
observat-ions
daca
The. characLer
in
inspected
indivi-duals
-consisEent
morphologically
thal
however,
c]early
show,
sets
Phase I are
during
East Kalimantan
with c. sjamensjs known from mainland
50
(Ross, 1990; Ross,
(Thailand
Asia
and vietnam)
southeast
in Kafimantan examined by Cox et af.
data), and ind,ividuals
unpubl '
(1993) '
crocodilian
ResulLs of a recent
oecufiedee
ia
the witd.
survey in the Danau (=Lake) Sentarum area? Kapuas River system of
patterned
of an unusually
included
a photograph
west kalimantan,
vllLage
(Frazier,
with
juvenile
1994) . Interviews
crocodyTus
Danau Sentarum and
in particular
in the Kapuas drainage,
residents
this
inhabiting
of c. siamensis
vicinitv,
showed nb indication
Visuaf inspeccion of sEock ar the P.T. cipEa
large r-iver system.
farm outside Pontianak also failed
Mandlrl crocodife
Khaiustistiwa
r^
ari6l.r
.h'/
6rri.lah^a
^-fi-- -l 1 e s p e c l e s .
From informaLion
in reports by Muin and Ramono (1994) , Frazier
and Maturbong's (1990) and cox et a-l. (1993), and a wealth of
(C.V' Surya Raya)
prowided by Messrs. Tarto Sugiarto
information
in East
(P.T.
surveys
Makmur A.badi Permai),
and l^rel]y Mikawang
River
system
in areas of the Mahakam
were conducted
Kalinant;n
where wild C. siamensis was reporLed !o occur.
or stream) Bongan in the lakes region of the
At Sungai (=river
huDter and
(Map
2), Mr. Safeh, a former crocodile
central
Mahakam
guided-the
juveniles
for capLive breeding,
supplier
of C. siamensis
geveraf
young
nests
of
and
sites where
su-tey team to
"buaya kodok"
to in the
(frog- crocodile)
referred
, as c. siamensis is commonfy
region,
were said to have been harvested.
(59.5'80 cn total
lenqth
[Tr,] ) being reared by
Four juveniles
Danau
came from nearby
in october
1995 reportedly
Mr. Saleh
(dry
depths
season
This is a larg'e1y owergirorirn, shallow
Belibis.
mats of reeds
floating
with
is fringed
of ca. 1.5 m) lake thai
hexandta '
,eetsia
aod
sp.,
hangtLrana Hanguana mafayana
Phraggites
for nests
search
an unproductive
restricted
oense, boggv vegetatlon
to the outer edge of the lake.
Danau
Another reported area of C- siarne'rsis breedingi habiLat,
Thls
.
km
channel
by
a
2
Bongan
Tanah Liat,
is aonnected to sungai
hanguana,
with
Eafl'
fringed
is
densely
isolated
lake
relatively
Idater hyacinth
draped with fianas.
reeds, and broadleaved thickets
and is braided
water
patches
in
open
as
crassjpes occurs
Eichhornia
years aqo Ene
20-30
since
its
introduction
fringe.
in the floating
and
grovrth
the
fringe
of
accelerated
weed
has
apph'ent1y
aquatic
constricted
the area of open water by almost half.
where c'
shoreline
has some non-floating
Danau Tanah Liat
individual
A
large
bask.
were
said
to
occaeionally
siamensjs
ca.. tv/o months
fishtrap)
a bu-iru (rattan
reportedly
destroyed
j-nterviewed
at this
vil-1ager,
another
sane
time
about thJ
eailier,
water'
the
in
floatj-ng
crocodlle
a
large
1ake, cfaimed to have seen
fringe,
floating
the
placed
in
w-re
bulrus
more than LOO
Although
hawilg been trappedwere received of young crtcodites
no rep;rts
juveniles
not been observed for
have
altiva
nests
and
Furthirnbre,
and/or recruaEnenE '
poor
success
nesting
several years, suggesting
spotlight
sulveys by pe.rahu
Two evenings were spent conducting
(paddfe caooe) in Danau Tanah Liat,
eyeshine was
but no crocodile
obsenred (see Table 5) .
i.n the Kedang Rantau tributary,
At Danau Mesangat viIlage,
in the
abundant
residents
reported
C. siarLensis to be fairly
adjacent
overgrown lake system (Figure 5) . A 73.5 cm TL juvenile
was obtained as a
captured in Danau Mesangat about 10 days earlier
locality
voucher for MzB.
'_'^-mation
siamensf3
that
C.
indicated
lakes, villagers
permanent marshlands aod small isolated
preferred
the
lakes
bordering
shallow
of several
large
in the vicinity
there.
occurred
C. sjalne4.sjs also
central
Mahakarn reported
that
said juven.iles obtained from
Kampung (=vi11age) Melintang residents
being informed
Danau Melintang were released in 1986 or 198? after
At Kampung Resak tqTo captive
that iL was illegaL
to keep them.
juveniles
at nearby
were said by the ow!1ez: to have been captured
Danau ,fempang.
NT
L]IVU:jII
TLUDL
CrocodyJus
siameneis
uninhabited
lake that can
sungai wahau, and several
Danau ceddang),
associated
difficulty
by perahu from
constrraints
none of these
and
was said to occur at Danau Sekentalg,
on
Bengkal
Muara
be reached by foot from
(including
or narshlarlds
6ma11 lakes
\dith sungai Keteng, and acceseed with
Danau Padam Api. Due to time and funding
sites were investigated.
at
observed
siameneis
C.
the
captive
At least
some of
of
Central
systems
came from western river
Banjarbaru
reportedly
there
(Kasan, falm caretaker,
pers.
colhm.). surveys
Kalima4tan
Jelaj
sungaj
and
Kotawar-ingan
the
sungai
during
Phase 2 in
Crocadyfusfound only anecdotal
evidence of palustrj-ne
drainages
resident
described
\^rere
used
to
lolal
names
Three
to
four
the
Kalimantan
In
East
anong them
crocodilians,
"buaya kodok".
varying
based
on
but
name is referable
only
to C. sjame.l?sjs,
an
of species photos during interviews
descriptions
and selections
tlle
rn
certain.
is
less
central
Kafimantan,
the exact species
claimed that
at several villages
informants
Sungai Barito drainage,
occurred
C.
siamensis,
resembles
"bu;ya kodok", which as described
of the
a
tributary
Al.u,
Bu)rui
on
sungai
in the area.
At Karnpung
inhabit
to
was
kno!'rn
kodok"
said
upper Barito,
residents
"buaya
buL fast seen five years earlier.
lakes and rivers,
rtbuaya kodok" was reported
to occur in the
In west Kalinantan,
at Kubu'
((etapaltg
hunter
former
by
a
area)
river
systens
southern
Pinggan
sultgai
1982
at
in
of
these
crocodilee
two
He cited catchint
in
lives
species
the
and
said
that
area,
in the Gunung l-alung
particular
in
west
Kalimantan,
areas
of
Irr other
freshwater
l-akes.
the Kapuas River systen,
-reports lhere was no mention of "buaya kodok"t
a
of
villag'ers
from
were received
howevei,
several
(toad
katak"
to
as
referred
CroeodyTis
freshwater
"buaya
described as aggressave,
was frequently
. this ciocodile
crocodilE)
On other occaslons'
from C. po-rosus.
ar1d distinct
dark colored,
'buaya katak"
sometimes 1n
tivers,
coastal
from
large
was reported
brackish conditi.ons.
c'
where successful
to Danau Belibis,
In addition
Ne'ti',g of
the
capture
by
1993
as
as recently
is inferred
Eiamensis n;sting
in 1995, Danau Tanah Liat was also claimed to be a
smalt juwenifes
(Craeodyfus
presumab.ly C. sian?ensis
nestin-g area for crocodiles,
sianensis,
C
wich
Ehere
sympacric
porosu; was said to be formerfu
_but
years) '
many
for
extirpated
the former has been reportedly
ot
mats
floating
as
Mr.
saleh
by
was described
habitat
Nesting
j.ncluding
found
sapt-Lngs,
and
hanguana
vegecation,
herbaceous
inl:r.l
frdm rhF frinde
ue could not recall the months when acEive
ne6ts were seen.
that Danau Pekah, a smaller lake S (?)
Mr Saleh also reported
maEs of vegeLacjon,of Danau Tanah LiaE, ind connected by ffoating
i]ad
Many years
atea.
nesting
good
C. sjafle]],si.g
was another
site'
secluded
this
visiced
since
he
last
elapsed, howe:]er,
by the
recounted
locality
breeding
C. siall,ensi'
The other
to
was
said
The
lake
v11lage.
near
Resak
was
Danau
Panan
informant
and
smaller
forest
by
surrounded
locality
hunting
be a former
-hunt'ed
C eiamensis for its skin for
fakes. Mr. saleh said he not
by
prices
and protection
1ow
to
past
or
so
due
decade
the
were no fonger pursued, he said'
Juveniles
gower:nment regulatj-ons.
found in bubus.
but were occasionally
was
Rahnan,
At'dullah
hunter,
and renowlred
Another
formel
He
Kanan'
Muata
of
center
in
the
district
at
home
intelvievred
from r94g/r949
afield
Mahakam and further
hunted in the central
s
j
a
m
ensis prefers
C
.
E
h
a
t
r
e
p
o
r
t
e
d
M
r
.
R
a
h
m
a
n
1
9
8
0
s
.
until
the
during August / september '
and eommences nesting
open lake habitat
mats in lake fringes
on floating
consttucted
N-ests are reportedly
swanp.
permanent
herbaceous
mixed
and
of the central- lakes region in the
Danau Mesangat, northeast
with open
mixed swamp woodland interspersed
Mahakam, is a diierse
mats of haDguana,
Floating
pools and hez:baceous associatrions.
spp'
sumaEranurn and sc_Zeria
hexandra,
ThoracostaclTyum
ieetsia
Eichhotnia
rntroduced
dis€ribution.
a patchy
sedges
exhibit
Local
open water surface
otherwise
co.rers *o._t of ihe
cralsipes
of
mats
on floating
fishermen said C. siamensjs nests exclusiwely
or
August
in
began to be laid
cfutches
herbaceous vegetation.
if
most,
to find eggs as
septenrlcer, buf october was the bestlime
by that time.
not alf,
nests were finished
eggs (MKI'I 001) was
of rotten
clutch
A nest with a partial
(Tabl-e
2) ' Egg size
1995
team it1 October
shown to the survet
(Bezr.!ijen- et,.af ', L995i T'
appears too small f-or T- schfegelii
the range
Although welf within
report) .
section
this
sLLlegeTii
in
lixt')
' C'
for cJptiwe c. sjamensjs i-n Tha.iland (Youngprapakorn-,
the
within
because egg Jize is also
be rejected
!"i""u'"
Furthermore'
iange of ""tt""t
this species (webb et a7., a9'7b; cox, l-985) ' .
in Kalimantan
upri"ver habitat,
evidence- af c. parosus in sinifar
study'
wis found in this
(e.g. Dainau Sent-arum, sungai Bila)
lEt-ore z.
Measurements of five eggs (in mn) from a nest at Danau
MesangaE, MahakamRiver, East Kalinantan.
ocEober -Lvv5.
WAclEN
88.0
aa.2
a a. ' ?
x =
83.1
Further
investigation
of nesting
in the Danau Mesangat and
Muara Kaman areas was carried out during 1995. Local fishermen said
year that
the previous
to C.
they could guide survey personnel
Fiame']sjs nests on floating
vegetation
from July through October,
but the only
active
nest6 6hown during
August return
our fate
proved to be T. schTegefii
- one inforinant
at Danau Mesangat opined
that our searches may have been too early because high water levels
had not yet receded to prompL nest building.
were
Local residents
requested
to report
forays
in
any active
nesas fouod oo subsequent
1995 to counEerparls
in Samarinda and Balikpapan,
but no response
was recei-ved.
ConserwatioD.
without
intensive
surveys
ernphasizing
population
monitoring,
it
is difficult
to infer
much about the
current
status
of C. siamensis in the Mahakam.
Considering
the
apparent
Mahakam,
extent
of
suitable
habitat
in
the
central
probable
lack
thereof
elsewhere
in Ehe river
system,
and Lhe
impressioal that our interviews
yielded
on most sites
information
inhabited
by the species,
the population
i6 roughly estirnated at a
maximum of a few hundred ildividuals.
The occurrence
of a lrild populatlon
in Kalimalttan is of major
importance
biology
of
to crocodilj-an
coDservation.
The ir
sjtu
crocadyltis
fev,/
siamerTsis and its
known, with
ecology
are poorly
(Kimura,
studies
of its
natural
history
available
1969,. Smith,
1919,1931).
The main population
of this species is in camicodia,
political
where
continued
make6 it
exceedingly
instability
populations
difficult
in Lao
to conduct field
research.
Peripheral
PDR and vietnan
appear similar
in size to the one in Kalimantan,
prospects
By
uncl.ear.
but
for
research
and conservation
are
contrast,
occurs in an area where study,
the Kal-imantan population
protection
and management is currently
feaeible
Trade in C- siamensis has evidently
cea6ed in East Kalimantan.
anirnals were examined at sungai
Although- small cluscers
of captive
the protected
Bongan and Muara Muntai,
area farm owners ackoowledge
purchase wild
they no longer
status
o-f the speci.es, and report
stock. Observatlons
by the survey team of faim stocks in Balikpapan
to the wild
and Samarinda supported this claim. The greatesc threat
Tntensive
and disturbance '
degradation
population
is
habitat
fires
that
ext-ent,
a
lesser
to
and
!,rith nets and traps,
?i;hing
the
are
drought,
severe
of
tines
in
wetland habi€at
."uup i"t"""
mai! causes for concern juvenile
trade ln-Lhe recent pasE
aspect of live
A fortunate
needed, a potentiaf
if
eventualfy
is that a breeding i-rucleus, and
in Balikpapan'
Rayasurya
c.v.
at
is secure
founder popufation,
the central
gubadults
from
directly
obtained
vrere
of 37
iot.f
"td.i
pers.
comm
(T.
), and are
juweniles
Sugiarto,
Mahakam as small
C- potoeus
hybridizing
separated from potentially
reared at P'T' Alas watu
of the 15 c. siamensis
About half
of
A pair
are adults'
Kalimantan
central
Utama near Banjarbaru,
were
nested in January 1995, but no hatchlllngs
them reportedli
produced from t clutch of 30 eggs (Kasan, pers.. comm.'l - To assure
reared
at
c.
siamen3is
populations,
of wild
itre tto.og"treity
from c. poro,sus. conmlnal stocks at
shouid be isolated
aanj arbai]
incfude
evidently
p.ti
Stmarinda
outside
Permai
u.k .t. Abadi
should be
there
species
size.
some of which are adult
frylrids,
of
practice
cutled'
hybrids
suspected
and all
slgregaiea
.The.
etrongly
mi;in;
c. sjamensis and c. porosui in common pens has been
(webb and Jenkins, 1991; Ross et a7., 19961 '
discoiraged
Mahakam
areas in the central
of known breeding
conservation
link
Danau
need topressing
is
priority.
There
al-so merits
Rantau
with sungai Kedang
sites associated
tutesangat, and ;dditio;al
Nature Reserve {62'500
strict
Kaman
Muara
with
nearby
corifirmed,
as
area in the
protected
only
is
the
rnix6d
swamp
degtaded
.
iftl.
ftil
A
area fot C' siamensis
oesting
Mahak;n and a probable
;entral
Mahakam)
(Perairan
sungai
nature reserve 6f ca. zoo,aao ha
strict
lake
distinctive
conserve
to
region
proposed
for
the
1"""
frir
oteaelfa
dolphin
and thJ rare freshwater
sir",ip forest.
iiiuitrC.
rerequire
nay
(MacKinnon,
reserve
.
The
1996)
brevirostriE
of
fisheries
t'he economic dependence on
to reflect
classification
most
the
of
one
is
region
lakes
the
but
1oca1 communities,
and the
in Kalimantan,
habitats
wetland
freshwaier
iapo-t".rt
for
need
urgent
an
c. siamensis underscores
oi uie"ainq
;;;;";;;
acti,on.
consefwation
in East
C' . siamenqis
Development of a management plan for
commercial
skinrr
the "classic
take into'accouni
Kalimantan ;hould
rearlng'
Harvestss of eggs from wild nests'
value of the species'
an
p-rowide.
may
of a percentage of offspring
and eventual tistockittg
nesting
and
wild
breeders
to protect
inceniiwe
local
of
to quantification
"ii..ti.r" u. well as a mechanism th;t contributes
ii.".,
(Ross, et af.' L995).
population status
removed from the wild population
At present rnost individuats
cau-ght in bu-bus
juveniles
accidentafly
of C. sj-arnensjs are small
fishing'
for
villa-ge-rs
ry
loca1
,l.6a
traps)
funnel
ii.it""may
young
farger
of
of eggs and release
incubation
AltificiaL
potential
against
but safeguards
in trteiira,
survivorship
r;;;;"";
a;i;ii;t
ti
tr'" urird population ihroush ei situ hvbridization
a prerequisite
(Ross, et af.,
L996).
55
are
In
6jtu
managehent must also
conlend
with
more general
conflicts
in
habitat
use by
local
communities
and foraging
crocodiles.
An integrated
pressure
approach
that
decreases
on
overharvested
fish stocks by enphasizing
development of alternative
sources
of
income may ultimately
provide
Lhe moBt effective
protection
for C. sia]nensis in the wild.
C. .raitjlus
Durlng Phase 1 no crocodiles
identifiable
as C. raninu,s were
observed
on crocodile
farm6 or in holding
facilities
in west,
CeDtral
and East
Kalimantan,
Interviews
of
viflagers,
farrn
personnel
and others
yielded
iD these provinces
no j-nformation
specifically
referable
to C. z:anillus In South Kalinantan,
however, a visit
by Cox in Decentcer 1995
to P.T. Alas Watu Utama crocodj.le
farm in Banjarbaru
revealed two
individuals
that
were
identified,
on
the
basis
ventral
of
(Ros6 eC a-2., 1995) . These
sqfuamation, as ranjnus group crocodilesl
(see Fi$-rres 1-4),
crocodiles
were captured,
photographed
sexed,
and measured for total
fength and ventral
squamalionTail scute
tissue samples from the male \^rere obtained on- a subsequent visit
by
Kurniati.
Tab1e 3.
Measurements of two captive
at
ranjnus group crocodiles
P.T. AIas Utana, Banjarbaru,
South Kalimantan.
Total
Iahdr
h
in
hal-a,c
Transvefse
scafe
Sex
length
9
d
1-a
Farm staff
fhe
^ridih
adamant that
year
peri-od,
PaDgkalanbun,
FhF<F
Transverse
throat
scale rows
24
23
were repeatedly
^F
ventral
rows
3'7
questioned
and carefully
rrhA
^r^^^;ilac
regarding
-:16F:Lar
Lhese anj-mals \dere obtained,
separately
frorA a loggingi
canp foreman posted
Central
Kalimantan.
over a two
at or near
The female was reportedly
1991 as one of
received
in early
five crocodiles
in a group that included
Leto C. poz:osu9 and tvro C.
siamensis.
Mr. Kasan recalled
measured
that the unusual crocodile
53 cm TL when it was received.
Tha
shipment,
m^la
again
ran^'r-ad1\'
^rriwFd
hand-carried
JuvcllllEL.PvLwEu..
'taxa of Tndo- Paci,fic
patternt
ventraf
raninus,
"_
by
ihF
in
the
rimF
crocodyfu,
mi'jdorensis,
56
1qq2
^s
foreman,
^f
nFr-
of
that
hIr.h:se
Lhat exhibit
novaegaineae
a
Second
included
l_he
crocodile
scale"
"large
and johnsoni.
22
jn
neasured 33 cm TL. It has since died {Moelyono, farm manager,
and
by othef crocodiles,
fron wounds inflicted
-Zitt.),
apparently
(
R
o
s
s
)
9
9
6
)
.
a
f
.
,
e
t
has been preserved as a whofe skin
requires
C- raninus
of
knowfedge
taxonoroic
Our currenl
the
species,
posiLively
ideotify
sutures to
examination of cranial
inadequately
srna11
and
known
are
because the only whole speclmens
preserved,
and Comparatite DNA studies of taainus group species. are
(a'e'
characters
morphological
identifiable
Even so,
lackinq.
to
used
pattern)
have
been
post-occipital
ventral
squarnation and
and
c'
mj]]dore_rrsis
c.
lesembles
predict
cfosely
ttat
C. raninui
n^\.2
adtt
i na2a
lD^cd
One interview
^r^-^rri
la
'an'
l
qqnl
Phase 2 suggested
durlng
eimi l:r
f^
if
m:1/
hcre:st
that
in
C. raninus,
the
ltild.
or a
The
a former
wis received
in July 1995 from Mr. Janain,
information
Sungai
Pandulang,
at
Kampung
and
trader,
crocodile
hunter
of
four
t)/tr)es
recognized
He
Kal"imantan.
Kotawaringan,
Central
T.
schfegel-ii'
syeten:
in
the
sungai
Arut/Kotawaringan
crocodilei
a common loca1 name for the
which he referred
to is "buaya sapit",
t'buaya
to the
a nane that refers
porosus,
or
toman!',
specie6;
C.
to as
alluded
Csiamensis,
KalimanLani
of
central
species in aieas
and
photo
sheet;
the
from
selected
kodok,',
al1d
correctly
"_buaya
shot of
picked
head/neck
the
.tamain
which
Mr.
saIak",
for
"buaia
body photo of
and the fess distinctive
the ianinus group crocodile,
sungai
inhabit
formerly
to
was
said
sa1ak"
c. eianensii
"iuaya
locally
extinct.
but
may
now
be
sebingit,
at Banjarbaru
group individuals
DNA anafyses of the raninus
this
although
identification,
in
species
may be instrumental
and
C.
mindorensjs
from
material
seriis
of
.eq,rir""
a
conparaEive
of the latter
C. nowaeguineae (north and south coast popufations
cox,
biologY;
in morphologY and reproductive
due to differences
1985; Ha1l, 1989; Ha11 and Johnson, 1987).
To'nistoE,a
EchTegeTii
false
as Ehe false gharial,
to variously
commonly referred
of
is
one
gavial,
Tamlstoma schfegefii
gavial,
atld i"talayan false
yet
known crocodilians'
leasL
distinct
Lhe most taxonoirically
in southeast Asia,
the speci?s was widely distributed
Historicafly,
alld Kalimantan,
sunatra
only
from
reported
but
is
eur:rently
-and
hefd
(Ross,
long
1998) . rts
peniosular
sarawal
Malay-sia
i'Endangered" stalus
by
the
revised
(Groofticridge, 19s2) was recently
'
s
p
e
c
ial
i
6
o
f
(IU(IN, 1994). The species
Data-Deficient'
IUCN to
to
was
forned
Tomistoma"
In ag94, "Project
concern to the CSG.
of
needs
and management
an assessnene of conservation
coordinate
peni'nsular
ill
stsudies
field
and has undertaken
specles,
the
while conducting
this effort
To not assist
I'talaysia and sumatra.
would have
of Kalimantan
habitats
in sympatric
ctoc-odyTus studies
on our part.
been neglectful
data
this
and
and wild T' schiegefii'
were nade on captive
observations
status
of
and
biologlt
relproduetive
on the ecology,
collected
whole
of
6eri'es
a representative
In addition,
species.
specimens
variaEion
and skul1s was assembled, primarily
Lo assist
in geographic isolates
af T- schfegefii-
of
studies
Occurrence in the wiTdCaptive ?- schfeqefii
were observed
i-n willages
of all
three provinCes where fieldwork
was conducted
(West, Central
and East Kalimantan).
Eighty
were
individuals
recorded,
usually
singtes
or pairs,
ranging
from small juveniles
(55 cm TL) to adufts
>3 m TL.
Most of these (47) were found at
Kampung Batanbang in DecenLber 1995 on a circuit
of tributaries
in
(MaD 3) .
the Barito
River,
Central
Kafimantan
Proof
?.
of
schTegeJ.ii (captives, skul1s, direcL 6ightin;s) , or reports of its
occurrence by loca1 residentg,
was found throughout
all nine areas
of reconnoitered
river
systems I upper Kapuas, Kendawangan/Balaban,
Simbar,
Pa&ran,
Air
Hitam
Kecil,
Jelai/Berais/Mapam/Bi1a,
Kotawaringan/Arut,
Barito
and Mahakam).
Almost aI1 captive
animals were naintained
in semi-submerg,ed
crates at the littoral
of watera/ays, usually
adjacelt
to floating.
residences
of viflagers
and tow-aspeople.
Some had obviously
been
reared for many months if not several years.
In the Kapua6 eystern,
villagers
surmised that captive
T- schlegeTii
would eventuafly
be
sold to itinerant
traders
for glands and skins.
This may explain
why relatively
(4? at
large
stocks were reared
in two villages
Kampung Batambang in the Barito;
eight
at Muara Aoggalam in the
j-n captivity
l4ahakarn), although
apparent
length
suggested
that
Erade in the species had ceased 2-3 years ear1j.er.
Most of the
other
individuals
were said to be keDt exclusiwefv
ae oets or
exhibition
curiosities.
The species appears suicable
lo;
these
purposes, owing to its more docile characier,
compared to sympalric
CrocodyTus, and peculiar
appearance.
Captive
?. schTegefii
were frequently
reported
to have been
acquired as incidental
catch (usuallv
smal1 iuvenileg)
in fishinq
neEs or bubus. Some evidence of pursuif
wa6 s;en - a juvenile
witi
a spear wound, a prepared skin, and a skull with a mortal bfow from
(machete) - but the intensive
a parang
fevel
of fishing
in many
waterways visit.ed,
ald lack of commercial dernand for T- schfegefii,
lent credence to much of the information.
In the Kapuas River
systen,
T. eehlegeLii
was observed at
three villages
near Danau Sentarum Wildlife
Reserve.
At Kampung
Meliau, another viltage
in the vicinity,
local guides said that ?.
schTegefii
occurred at Danau semati.
This is a smal1 lake fringed
!,rith fl-oating
pandan Pandanus 6p. that usualfy
anchors
during
the
dry season.
No crocodilians
were sj-ghted on a night
spotting
circuit
of
the
flooded
lake.
Tomjstoma schl-egefii
was also
(partial
reported
to
occur
at
Danau Lintang
pandan
floating
fringe),
and to be sl,'rnpatric with
C. porosus
at Danau Merbong
( swamp forest
border).
Sungai Leboyan, a known locafity
for ?.
gchTegeTii
(Frazier,
1994) was said by Kanpung lvleliau residents
to
1'
E^hladal
season, but disperse
i;
in
to adjacent
iha
,,hh6r
rA.^hAc
swanp forest
.+r,ind
tha
d.\/
when flooded.
surveys were also conducted in remote tributaries
Kalimantan that
are part
of the proposed 150, 000
58
of West
ha Muara
assessed as
The area was recently
Kendawangian Nature Reserve.
peat s\damp
a-nd
freshwater
of mangrove,
for conservation
importanL
in
proposed
reserves
and
existing
all
other
and unlike
foiest,
'rnot
(MacKinnon,
Sungai
1996).
threatenedrr
1o!,7tand Kalimantan,
habitat
showed moderate - serioue
Balaban
Kendawanga:1 and sungai
and
waterways
of
use
and intensive
from
logging
disturbaice
local
by
was
seid
Tomistoma schTegeTii
adjacent lakes for fi;tinq.
was
eyeshine
but no crocodile
the rivers,
to inhabit
reEidents
a
Kecil,
(Table
Hitam
Air
5) . sungai
systern
in either
recorded
peat
through
wends
that
smafl river
pandan
and hanguana frlnged
'""..p,
although -none had been
the species,
to hirbor
t"" alsJsaid
narrow
of thi6
reaches
The lower and middle
seen in many years.
of
extraction
by
recent
disturbed
hiw,i been seriously
tributary
(Table
'
5)
eyeshine
no
A oight count there tielded
tinlcer.
far: T' schTege-Zjj was
habicat
West and centraf
bordering
.felai
of
found in tributaries
sungai
branch'
(Fig.
upriver
its
s), and
Kalimantan.
sungai Mapam
system'
in
the
habitat
comprise perhapJ the least disturbed
Bila,
up
-a.large ?i schTSgeTii was sighted during the day on an excursion
in
the
count
juwenile
a
night
on
was captured
the Bifa, and a 5ma11
found
Nesti were said to be easily
Mapam under flooded co;ditions.
An
Mapam'
middle
in
the
to Pondok Palas
in s$lanps adjacent
?'
that
sugigested
Berais,
sungai
at Kampung Buntar,
informant
tributary'
narr-ow
fengthy,
ptentiful
in that
sehTegeLii was fairly
congiregate during the dry
Mr. Nrfan estirnated thai 1o-20 individuals
BunEar to che confluence
from
of deep channel
season in a section
with the Jelai.
intact
-Sungai
observed j'n the
r- sehlegeTii
In addition
to the many captive
anecdotal
substantial
River system of Ceniral-- Kalimantan,
Barito
Arut and
in
the
ltas
collected
occurrence
arria"tr"" of the- species'
of
Reports
province
'
part
the
of
western
in the
Lamongan riwers
Daoau
at
nesting
recent
and
Rampung
Pangkut,
captuiee i1l 1995 near
to the survey team' Tn the lower
eair and Sungai Jampau wert related
be good fat T. schJ-egelii'
said
to
was
sebingit
r.eaches, su;gai
Park (3OO,4OOha) in Central Kalimantan
Tanjung
Puting - National
-suiweyed,
?'
area for
as a! important
reported
but
is
was ltot
Lhe
with
(MacKinnon,
l-995),
porosus
in
K;timantan
and'c.
siiligelii
conm' )'
abundant (Abdul Muin, pers'
formei species falrly
of
and observations
from interviews
Infornation
Habitat.
broadfy
is
sell-lege-lji
T.
that
wild
indicates
in the
individuals
The
systems of Kalimantan'
river
in the fowland
distrj,buted
1n
occur'
to
reportedor
encountered,
often
was most
species
usualfy
and stagnant
tributaries
freshwatet
.ir.g!j-.lt
-lakes,
are
margins
lak€
and
waterways
peat
forest.
swanp
with
information
No
"ss56iated
wi-th pan-dan-hanguana associations
fringel
ivpi"-ilv
or
brackish
in
occurs
;ch-lege-ljj
I.
that
Juggesting
r,ra-srece-ived
saline waters.
sch-leEre-lii in the
wj'th-?
is slmpatric
croeodyTus sjamensis
.
syslem, buC evidence of habit.at partitioning
Mah;kam river
central
These were
with both species'
familiar
by informants
rr]gg..t"a
"i.
59
hunters v/ho said that T. echTegel-ii
afmost invariably
experienced
is more
while c. sjamensjs
is found in lakes,
streams and rivers,
permanent herbaceous
environnents:
likely
to be occur in static
swarops and fakes.
were
nests
During
Phase 2 faut
T. schLegeLii
NesEing.
to the
and one other,
freshly
raided nest was attributed
inspected,
Mahakarn except one
species, A11 nests were located
in the central
Recreation
Park, north of
in a captive
facilj.Ey
at Tengkiling
Central Kalimantan.
Palanqkaraya,
from
Hatching data from these nests (Tab1e 5) and information
consistently
in west,
centraf
and East
Kalimantan
interviews
for this
species is from July/
indicated
that the neEting period
dry season in
This overlaps
the lornal
August through october.
to avoid
East Kalimantan.
affording
land ne6ts the opportunity
floodinq
in nost vear6.
Three
1)
2)
tlt)ee
negting
habitat
were noted:
Mixed freshwater
swamp. composed mainly of fire-climax
mats of grass,
herbaceous vegetation,
mostly in floating
standing
sedge and short fern.
Includes patsches of trees,
deadwood and thickets.
secondary
].'a' cm:l
n,^rrn^
3)
of
l
forest.
cfa:mc
Lowland
-nA
rradaf.ri^h
i-
f^,
frhi^:l
in
S'rnarra
rqq6)
llqqq
l:rda
rraa<
ih
rha
h^.t
ll
Peat s\ramp.
Nests constructed
hummocks as degcribed by Bezuijen
n-arind
dissected
rainfoxest
tropical
I ^dda.l
at tree
bases on peat
ec aL for T. 6ch)egeiii
e
Kalimancan
(MKM 005) were heavily
draped itith lianas.
nest site
surrounding
herbaceous vegetation
was hanguana, sedges
and wacer hyacinth. Subject to flooding.
Table
4.
Neat
code
MICII 003
T- schiegefii
nest data, 1996.
Only nests in the nild
included.
NR=Not Recorded due to di-sturbance of nest from
eqq colfection.
Habitat
width
(cn)
Height
(cm)
Distance
co waler
(m)
Material
leaves
Secondary
forest
clutch
MKM u u 5
! loaEt ng maEs
i h
& twigs,
^r.rr-linarl
135-155
55
hFrfi^nFnt
at
base
chamber
Leersia
& ferns
leaves
& twigs
s\tamp
006
Peat swamp
mound/forest
N/R
N/R
&
ca. O.2
N e s t M K MO O 3 ( F i g . ? - 8 ) w a s l o c a t e d a L 0 o 3 2 ' 2 0 ' N 1 1 5 0 4 1 ' 4 9 r E
on 24 August 1996 aE the edge of an overgroMr channel. The site was
witil
and the channel overgrow!
mostfy overhung wlth small trees,
The
nearby'
thickets
grass
with
flooded
Leersia
water hyacinth;nd
that
clay,
orange-white
finely
speckled,
was
lined
with
egg chanber
A taif
than the other nest mateLial'
different
wi.l conspicuously
no adult was seen
Although
presettt
g.oon" rls
on the nest top.
durlng examilnation of the nest, waler nearest the nest was recently
About 3oO m aqtay was another nest (MKM 004) that had
disturbed.
but since raided by a wild boar (spoor
a
month earliet,
beelt active
preserlt) . A1l that rernained of the clutch were egg she11 fragxnents '
N e s t M K Mo o 5 ( F i g . 9 ) w a s l o c a t e d a t 0 o 3 1 ' 0 1 n N 1 1 5 o 4 1 ' 4 0 ' 8 ,
The mound was a soggy nass of decaying
24 August 1995.
a16o on
The
mat
floating
on a flimsy
constructed
herbaceous wegetation
because ?.
to be C. siamensjs,
informant
assunred the species
of
No reports
on tand.
was said to nest exclusively
schfegeTii
and
during the study,
nests rirere received
fJ-oating T. lchfegeTii
of the species in the wild.
noDe ar; known frJm the few studies
Danau Ngj-bun
at
was focated
10)
MKM OO5 (Fig,
Nest
(eoconpassed by Danau Mesangat), Oo32'Istt N 116o41'l-2r E on 26
luas unsure of the species but said that
Aug:ust 1995. Tlie informant
Eggs had been translocated
only c. s-iarneasjs nested in the area.
in wood shavings, but
incubation
for artificiaf
sewlral weeks prior
in the day.
when inspected
later
none were alive
Data for
all
clutches
examined are presented
below:
frori
Kalinantan,
data
clutch
TschfegeTii
Table
5.
(range,
n) .
deviation
are
with
standard
Measurements
at
incubation
followed
Hatching
not recorded.
temperatures
Nest
code
Clutch
MKM 003
32
MKM005
23
Egg mass
(9J
central
Kalamantan
27
Egg width
(mnl
188.219.81
1165-2a4,
n=24)
93-1r4.00
(83-3-100.0,
n=29)
60 . 010 .78
I8'7.2t9.48
92 .8!3 -22
(88.3-101.3
n=20)
59.8r0.87
n=15)
MKM005
Egg length
tmml
209.5110 -43
(L95-238,
n=25)
\\74 -213 ,
97 .4!3 -52
(93.0-106.5,
n=261
{88. s-101.5,
6l
1995 '
cluLch
30oC'
Hatchingr
1-2 /LA
n=29)
n=20)
61. 810 . 83
(59.5-53.0,
5 9 . ' 7l A . 5 9
15a.7-60.e,
eggs
dead
infertile
&/or dead
(i.ncluding
in other focalities
Nesting information
collected
clutches
are
T.
schfegefii
river
systems) suggest that
additional
in
One
wonan
predated
monitor
lizards.
by wild boar and
conmonly
year
and
before
finding
a
nest
the
the Sungai Arut area told of
taking the eggs to eat.
in
declined
has apparently
Tomistoma schlegefii
canservation.
the
assert
that
provinces
hunters
of Kalimantan,
although elder
all
1ow abundance (compared to
in relatively
species was distributed
prior
of
hunting in Lhe late 1940s
to lhe commencer0eot
CrocodyTus)
yet
(A. Rahman, Ibrahim,
pers.
thin
comft.
saleh,
) . A broad
the
logistics
complicates
across freshwater
habilate
distri-bution
of Lhe species.
regearch and conservation
of ecological/biological
for
smal1 secluded
preference
The apparent
af
T. schfege]ii
and in flood
floating
veqetation
waLer\rays,
often
choked r,rith
problematic.
population
more
evelt
stage, nakes direct
studies
also compounded
and nanagement _are
Challenges to conservation
..41
\rh: l-Ff
hv
hw i nrersi we rrri I i zel i on ^f
communiEies.
areas
reconnoitered.
were
fiehed
in
a1f
Freshwater habitats
heavily
and
Villagers
in the lakes region of the cenEral Mahakam, Je]ai
(declining
size of fish
Danau sentarum areas cited overllarvesting
economic liwelihood.
to their
and total
catch) as the main threat
L997, roany
fires
in
and forest
combined with
severe
drought
villagers
in the Dartau l4esanqat area are said to have turned to
gold mining in the Mahakan headwaters to generate basic income (T.
a,,di
-rF^
harc
-^mm
)
(Bezuijen et af., 1996)
The low skin value of T. BchiegeTji
to conserve
strategy
hinders employnent of a commercial utilization
to conpete with
harvesting
the species.
Inability
of T. schiegeTij
to
strategY
means that
any effective
ocher land uses probably
on collllnunity
to
rely
conserve
remaining
habitat
will
have
means of income
development interventions
that generate alternative
(to reduce the pressure
fishing
and loggitlg) , and
of intensive
perguading government authorities
to set aside key areas of habitat
fron extraneous,
non-renegrable development gchenes.
conclu6ions
A wild populac lon of crocodyTus siamensjs was documented in
Based on recent
the Mahakam River
system of East Kalimantan.
nesting
of reported
in Ehe vicinity
capture
of sma11 juveniles
as
as recently
to exist
areas, a breeding population
wae i4ferred
1993. considering
the apparent fack of hunting for skins, breeding
Mahakan,
very 1ike1y persist
in the central
crocodiles
and
observed by Frazier
that
c. siamensis
The possibility
fron
(1990) and cox et a-1. (1993) may have originated
Maturbongs
farms oL other facilities
1n Java or mainland Southeast Asia \,ras
the h]4)otshesis that this
As noted i1l Ross et af.ll-996),
disproved.
ttade is
population
was translocated
through 16th or 17th century
for several
reasorts:
unlikely
62
1) .
several,
evidently
in
the
€iamensis
PuPufaLfurr
should
,w. a- -s
reflecE
a-
endemic,
Mahakam
Fr^n..-r
vrvuueL
^r
local
River
for
c'
names exist
this
If
systen'
:--'^drr-fi^r
COmmOn names
such a Phenomenon.
2) .
in the region
traders
early
that
is lacking
Evidence
item or
as a commercial
either
crocodiles,
transported
(Andaya, 1981) .
tribute
3) .
of C. eiamensis in the Mahakan
distribution
Historical
some
sy6tems,
river
possibl-y
adjacent
other
and
from
is
reagonable
watersheds,
diffe.ettt
comprising
(Inger and
znaacncanhi e natterns
fishes
of freshwater
sea fevel
1989) and Pleistocene
chin, 1952; Roberts,
(Inger,
1966; Uiibrove,
in the Sunda region
variations
is
of the Sunda region
The paleozoogeography
1949) .
possibly
and
current,
understanding
to
critical
fauna
and othel
rFl i.r-,ral
dis1-ributions
of crocodiles
(Ross et aL. 1996) .
anecdotal
substantial
project
accumulated
the
Although
and to a much
Kalinantan,
in central
evidence o{ c. siamensis
lesser degree from southern west Kalj'mantan, the species could not
Proof of a wild
system.
the Mahakam river
outside
be confirmed
the
strengthen
would further
Kalimantan
oopulation
in centfal
j's
natsuralIy
Kalimantan
in
siamensis
that
C.
ii-ketihooa
River systems in Central Kafirnadtan are effectively
distributed.
from those io East Kalimantan by the Meratus mountains '
isolated
wild presence of the species in both watersheds would otherwlse
exogenous introductions.
by multiple,
have io be explained
was found in this
No evidence of a wild C. taninus population
Eh-ree palusErine
suggest
of
-incerwiews
but
resulcs
study,
sungai
(and nay persist
the
in)
.roc6dilians
have inhabitsed
Alf
Kalimantan.
Central
system
of
riwer
Kota\rari,ngan/Arut
receot
in
declined
populations
theie hawe apparently
crocodiliin
species
to clarify
may serve
surveys
decades,
but laaitional
relaLionships'
on ecological
insighL
composition
and provide
did
observed in Banjarbaru
group individuals
If the raninus
their
then
Kafinantan,
trorn ttrl wlld in Central
indeed originate
nindorensi5
probable.
crocadyfus
idenriLy
al c. raninus is highly
of
lirnit
proximate
southern
due to iLJ f;iily
is a possibility
far
Eoo
is
(islands
nowaegttineae
N of sabah) , but c.
distribution
This is unlikel-y
unless the species was introduced.
extralinital,
(none
juveniles
of which are
of
shipments
as intra-archipelago
1980s'
labe
in
the
only
Borneo)
began
in
known to have arrived
the
are needed to cfarify
sanples
of tissue
DNA anafyses
gpecies
1n
crocodyfus
three
the
of
relationships
taxonomic
group
ranjnu's
the
of
identity
the
in particular
Kalimantan,
C. siamensis population
of the disjuncL
and iftinity
individu;ls
with thoge in nai-rlland southeast Asia.
63
Totnistona schlegefii
was found in afl
reconnoitered
river
systerns.
Although
trade
for
skins
and glands
has apparently
ceased, numbers of T. schTegefii continue Lo be hefd in viflages.
This species was the common crocodilian
encouotered
in surveys of
freshwater
habitat,
but its ecological
requirements
remai! poorly
understood.
In the upper Xapuas River, T. schfegefii
was sympatl.ic
with C. porosus,
and with C. siafnensis in the Mahakam. Although
there is pressing
need for fo1low-up
studies to provide additional
data on distrlbution,
abundance, breeding biology
and ecolog-y, ?.
schLegelii
in Kalimantan is evidently
Endangered, as
not Critically
defined by IUCN (1994), and is more appropriately
categorized
as
Endangered or Vulnerable.
Several areas that
for
Che species
merit
programs .
were appraised to cornprise critical
habitat
protection
fornal
management
and active
a
For C. eiamensjs:
and
Danau Belibis,
Danau Tanah Liat
sections of Danau l4esangat in the central
Mahakam are fairly
intact
and apparently
represent
The
crucial
habitat
for C. siamensis.
species likely
inhabits
nearby Muara Kanan Strict
Nature Reserve,
but this nixed swamp of trees,
thj-ckets
and herbaceoug vegetation
has been degraded by sewere burning
in recent years.
a For ?. schfegel-iit
Sungai Mapam, Sungai Berais and Sungai
Bi1a, which are minimally-moderatel-y
tributaries
of the
disturbed
Jelai river
system in Weat and Central Kalimantan.
The relatively
Iarge numbers of captive
aninals
in
observed in the middle Barito
Central
Kalimantan
suggest that
area may contain
inportant
this
habitat
for the species,
although exact locations
renain unclear.
Danau Jeras and snal1 lakes associated
with Danau Sentarurn (West
Kalimanlan)
and Danau Mesangat (East Kalinantan)
are lakes with
iatact -mininally
peripheral
where
Tdisturbed
vegetation
schTegefij
was confirmed present.
The e4tire
central Mahakam warrants Drioritv
in Kalimantan for
tuture investigation
The mosc
of C. siamensis ana I. scftIege]ji.
e)<tensive inland area of palustrine
habitat
in the four provinces
is found in this
heavily
utilized
lakes regionVast areas of
freshwater
swamp are found in Central
Kafimantan,
but large areas
are being converted
for a huge rice production
scheme.
Much of the information
in
crocodilians
obtained on palustline
chis study came from local
familiar
with
crocodiles.
informants
fheir
reports
often
constitute
evidence,
important
anecdotal
especiafly
where coosistency
among informants
is shown, a!:d \,\rhere
sources are forner
hunters well -experienced
with 1ocal crocodile
populations.
In the absence of written
such
records and reports,
knoi'1edge is valuable
and status of
for gauging former distribution
crocodilians
in
with
curtent
Kalinantan,
a]1d for
comparieon
observations
and conclusions.
Anecdotal evidence from preliminary
for
surveys
over an innense
study area helps
lay the groundwork
support
more inteneive
future
key sites,
surveys by identifying
personnel,
tining
and logistic
considerations
that save substantial
time, effort
and lirnited
funds.
64
Ack$owledge$enta
to the many people who supported
We are grateful
project
and were instrumental
in its success.
this
research
Ms sdcn,rii:di
end Ms. Krisbiwati
of Interof the Division
at every turn
LIPI, Jakarta rtere helpful
Institutional
Cooperation,
wj,th proiect
involved
hurdles
with
clearing'
the admi-nistrative
permits,
and
implementation
obtaining
the
various
approval,
facilitatlng
exte]lsion
of Phase 2.
from our in!\ras received
Excellent
administrative
support
the Research and Development Center fo! Biologi
country
sponsor,
Scientific
Prasetyo,
Head of
LIPI.
Edi
B.
lPusfixbang),
were
predecessor.
Darnaedi,
his
collaboralion,
and
Dedj
particularly
supportive.
of
Director
We also wish to thank D!. Soetikno Wirjoatmodjo,
interest,
Pu'Titbang,
and Messrs. Amir and Boeadi of MzB for their
encouragerneDt and support.
General of Forest Protection
Our coLleagues at the Directorate
gracj-ously
(PHPA), Ministry
of Forestry,
and Nature Conservation
permission
provided on very short notice,
to conduct research in
to Director
protected
We are thankful
areas and collect
specimens.
widodo Ramono, Head of the
General- Soemarsono, Dibyo sartolto,
and Effendy Sumardja, forner Head of the Bina
Evaluatio!
Section,
assistance,
encouraltement and
liaison
iPlanning) Program, for their
support.,
Forestry
At the field
fewel,
officials
of the Regional
(.t(anwjl ) and regional
are warmly
arms of PHPA (fstA)
Offices
logistics,
f acilitating
acknowledged for endorsing olrr activities,
a]1d their
on crocodiles
and providing
tocality
information
habitats.
Heru Basuki, Regional Forestry chief of East Kalimantan,
( t(aniVi-Z assistant
Ade Rachmat, KSDA
representative),
Sirajudin
in that
helpful
Agus were particutarfy
Head, and his
assislant
provioce .
in each
to have KSDA counterparts
We were also
fortunate
conlributed
province
and efforts
whose knowledge,
enthusiasm
In
greatly
conduct of surveys.
to the successful
and enjoyable
of
Tanjung
Head
to Herry Susilo,
this regard,
we are most grateful
his
detailed
for
Kalj.xoantan
Puting
NaLional
Park,
central
on area
us
Muin
to
assist
officer
Abdul
information
and allowing
excellent
for
Palangkaraya,
surveys; Costant Sorondanya, Head, KSDAhis
active
for
Pak Fahmi, (sDA-samarinda
coordinative
support;
KSDA,t.
simanjantuk,
and
participation
in the Mahakam River area;
pleasure
to
coflaborate
were
a
bontiantk,
KalBar.
These officers
with, and their
keenoess augere well for the prospects of foflol^'-on
studies
in Kalimantan.
crocodilian
of the Regional Forestry
Thanks are also due to ,.I. soedjanto
and DaDesaoke of the
Messrs. Darodjat
Office
in South Kalimantan,
Pak Wawan
office,
Buntok, Central Kalinantan,
Proviocial
Forestry
65
of the Kanlril office
in West Kalimantan,
Semitau for their
assistance.
and Yefri
Dahtain
of KSDA
Results
would have been considerably
without
dininished
the
:.1
Fy.al lF-r
..^^ar.r-i^n
^f
commercial cfocodile
entFrnriaes
Kafimantan.
Tarto and Susan Sugiarto,
Aldil
and other
staff
of
(Managing DirecLor) ,
C.V. Surya Raya, Balikpapani
Darma Surya
Moelyono (Area Manager), KasaD and oLher staff
of P.T. Sapto Argo
Unggul,
Banjarbaru,.
Messrs. Nurdin,
Dekus, and Bambang of P-T.
Cipta Khatulistiwa
Mandiri,
Anjudgan (Pontianak) and welly Makawang
of P.T. Makmur Abadi Permai, Samarinda have contributed
enormously
to the success of projectPersonnel of Asian Wetland Bureau (AWB) associated
with the
Danau Sentarum Wildlife
Reserve
Conservation
Dro-iect
in
West
Kalimantan,
facilitated
our surveys in the Kapuas ;iv;r
system.
we
wish to thank Mike Olmstead, Dj.rector,
AWB Indonesi,a Program; Kevin
Jeanes, Project
Leader; Aidi
Erman, Trevor Wickhaft and Budi coyang
at Tekenaog, Danau Sentarum; Pak Anran in Pontianak,
other
AWB
field
staff,
and collaborator
Julia
Aglionby
of .the
Overseas
(ODA) .
Dewelopnent
Agency
Thanks too,
to Herry Noveriai/an,
AwB
Training
Officer
in East Kalimantan.
we greatfy
appreciate
the services,
wealth of inforination
a!1d
fine hospitality
received from 1ocal residents.
Those who deserve
special- nention
are the late Pak Saleh and famify,
Sungai Bongan;
Pak Dila and family,
Kampung (Kpg.) Mulupan,. Abdul Rahman, Muara
Kaman; Pak Ahoi, ,fongkong; Haji Yan, Pak Unung and fam11ie6,
Kpg.
Batanpangr;
Pak Berau, ketinting
Ndai,
operator
Kota Bangun; Pak
nest
informant,
Nusa Palung,
ketinting
Mahakam River;
Idi,
operator,
Kampong Danau Mesalgat,
Mahakam River;
Pak Labe, ,Jumran,
Doi, and Harni, nest informants,
Kanpong Danau Mesangat t Pak Lok,
nest
infornant,
Teluk Parit,
Mahakam Rivel
Pak fdan Mahdari,
speedboat
operator
extraordinaire,
Pangkalanbun;
Pak
Batut,
Sukamara,' Pak Elhami and lbrahim,
hunters,
Kpg.
tormer crocodile
gungai (Iefai;
Nantakuini,
,leha,
Arut;
Pak Edin
S.
Kpg. Pangkut,
forner
crocodile
hunters
Pak Aruat,
Kpg. Nangamua, S. Arut;
Pak
Jamain, Kpg. Pandulangao, Sungai Kotawaringan;
and Pak Isarn, Kpg.
Muala Sungai Bufu, Sungai Bulut Leo Laloan,
and Chuck and Shanti
We would also like to thank S. Descheemaeker, S. ,Jones, and C.
of the National
Museum of Natural
History,
Smithsonian
-nct-i-..ri^n
Potter
F^-
r\a:r
-:_inistraEive
supporE.
G. Ross and a donor v.rho ivishes to remain anonymous provlded
financial
support
for most field
activities
of Cox and Frazier
during 1995, and we greatly
appreciate
their
assistance.
.f. Lazefl
of
The Conservation
vrithout
Agency
adminisLered
these
funds
overhead charges, and this generosity
time
allowed much additional
in the field.
the range and
Without the support of these persons,
intensiEy of Phase 2 activiLies
reduced.
would have been greatly
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mindorensi'
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novaeguineae
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Johnson. 198?.
Lake Murray
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l-885.
Willian
T,
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rndia,
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and zoogeography
R.F. 1956. The systematics
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a
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o
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Ehe
Ehe
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Inger, R.F. and P.K. Chin. (1962).
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IUCN Red List
Survival
Commission.
Kimura, W. 1969.
and Alfigator
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i ah
Categories,
Prepared
c1and, Slritzerland.
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of North
by the IUCN Species
2a D.
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Fann, Res. Rept., 3:1-23 (in Japanese with an
c,,mm:
nrl
(1996) . The
MacKinnon, K., G. Hatta, H. Halim and A. Mangalik.
ecology of Kalimantaa.
Periplus
Editions.
xxiv +
Singapore.
802 p.
Muin,
A. and RanoDo, W. 1994.
Preliminary
survey of buaya sumpit
(Tomistoma schfegelii)
and buaya kodok lcrocodyfus
siamensis)
j.n East Kalimantan5 p.
Report to ACSUG and CSG. Unpubl .
Muller,
S. and H. Schlegel.
1844. Over de Krokodillen
van den
fndj.schen Archipel.
28 pp., pls 1-3 in Temminck, C.J. 1839
1-a44geschiedenis
Verhandelingen
der
over de natuurlijke
Nederfandsche
der
overzeesche
bezittinqen,
door
de leden
Natuurkundige
commissie
in
Indie
schrijvers.
en andere
l,erden, 259 p., pls. 1-?0.
Roberts,
T.R.
1989.
The freshwater
fishes
of western
Borneo
(Kallmantan Barat, Indonesia) . Mem. Callf.
Acad. Sci-, 14:1-
2ro-
Ross,
C.A.
1990.
valid
species
Borneo.
Ptoc.
Crocodylu€ ra.njnus S. Muller
and Schlegel,
a
(Reptilia:
from
of crocodile
CrocodylidaeJ
Biof. Soc. Wash. 103 (4) :955-96L.
Ross, C.A. 1992. Designation
of a lectotl4)e
for Crocodylus raninus
(Reptilia:Crocodylidae),
S. MilIe!
and Schlegel
the Borneo
crocodile.
Pz:oe. Bial.
Soc. Wash- 105(2) :400-402.
Ros6,
C.A.,
G.C. Mayer and R. Bour. 1995.
Designation
of a
lecEotype
far Crocodylus siamensjs Schneider 1801 (RepciIia:
Crocodylidae)
Proc. BioT- Soc. Wash. 108 (2) :298-301.
Ross, C.A., J. Cox .Tr. and H. (urniati.
survey
1996. Preliminary
of palustrine
Phase 1.
Project
crocodiles
in Kalimantan.
nr-dress
ran-rlDh:se
dan
1 - 1995.
Pusat
Penel-ilian
PengrembanganBiol-ogi (Puslitbang) /LIPI,
and Dept. Vert- Zool .,
Smithsonian Inst.,
USA. vi + 45 p.
Ross, J.P. (ed.) 1998. crocodiles.
Actj-on Plan.
2nd edition.
Group. IUCN, Gland, Switzerland
snith,
M.A. 1919.
crocadyfus
- 2 2 1 -.
3 \3I :21-'7
status Survey and conservation
crocodile
specialist
IUcN/Ssc
+ 96 p.
and Camlcridge, UK. viii
siamensis.
68
'f. Nat.
Hist.
soc.
siam,
smith,
including
India,
M-A. 1931. The fauna of British
Loricata
vo1.
1.
Amphibia.
and
neptilia
iurrna.
+ 185 p'
London., xxviil
Taylor and Francis,
ceylon and
Teetudines '
W--e b b' , G . , I . w . , H . M e s s e l a t l d W . M a g n u s s a r ' ' L 9 ' 7 ' 7' T h e n e s t i n g o f
copela
cioeodyius porosus in Arnhem La;d, Northern Australia'
(
2
)
.234-249 .
L97'7
'Webb,
in
G.J.w. and R.w. Jeokins. 1991. Management of crocodilians
National
Australian
'
reconmendations
with
Tndonesia: a review
Canberra. 47 p'
service,
Parks and wifdtife
69
Night counts of crocodilians
in i{e6t (WK), Cenrral
{cK) and East
(EK) Kalimantan provirces,
!995-!996.
Ts=Toiniseoma
*= assumed TS. o= assumed
CP=Crocodylus porosus. CS=C. sianensis.
cP. E=tratchllng.
.I=juvenile . A=adutt . Eo=eyes onty.
Date
Star!/end
s. Kapuas
w(
kn
TslcP
10
tt205t'48"
E/
S. Sibau
2A
0003,55" s
D. Termabas
18-8-96
WK
rslcP
20
0045,s0'
N
1 1 2 0 30 ' , 3 9" E
25-A-96
WK
2A-a-96
s. Belaban
2A-A-96
s- simba!
22-9-95
D.
TS/CP
1649',31" S
ltK
15
25
TS/CP
7
Pengemlcung
4 -a
(ci!cuit)
24-9-95
D- Basaufaut
5 '1
{circuit)
5-9-95
D.
6-9-95
D. Tanab
Tanah
Liat
LiaE
3
cs?/TS?
m
oo29,2o'
6
3
!I
J EO Density
km
surv'd
start/end
coordinates
16 -9-96
29-9- 95
D. Belidas. Befida-
wK/ Ts/cPlcs
CK
2050'03n s
110o58.08n E/
S
\\oo44'!2n E
s
S. Kedarg
E
1*
42.5
72
.r Eo Denslty
1
61.
4.o24
0.11
s
t16.43'
13-9-95
11-9-95
s. Mapam
s,
Air
gitarl'
vtK/
CK
23h E
s
Ts
32
E/
2042! 3A\ s
111010',05" E
wI<
CK
2.47' 59'
110023',53"
2.54' 57'
s
s
E
11
T1
0.03
tl
Sandakan
DSWR
9
\
Vru"
Samarinda
alikpapan
a
9,
Pangkalanbun
Banjarm?sin
kn
a--.----221
ltap 1.
rsland
of Borneo sho'ring major featut:es.
'72
""'"'""
/i
N
-(
LiangBuaya
aM.Kaman
t-'
D.lall.tt.atc
"'o "-! ..
'9o
Srm!rlndt
M.Muntai
\
A.llbls
0
BallkPaPan
50 knr
0
ttap 2.
Mahaka$ Ri.ver
sysLem.
East
Kalimantan,
N
Ketapang
r. Batilap /
115 E
Map 3,
Barito
Rive!
sysrem '
Centlal
KalirnanEan '
FiglreL
Figure 2.
Dorsal view of ca, 1,8 m fL nninus group crocodile.
P.T. Alas Watu Ubma, Baniarbaru,KalimantanSelatan"
Laleral view ot 1,4m fL raninus group crocodile
Selatan.
?.T. AlasWatu Utama, Banjarbaru,Kalimantan
ls
lignre3.
Ventral view of 1,4m IL faninus gaoup crocodile.
P.T.AlasWatu Utama, Banjarbaru,Kalimantan
Selatan.
1.
Irigure
Dorsal neck view of 1.4 m IL rcninus group crocodile.
P.T.AlasWatu Utama, Banjarbaru,Kalimantan
Selatan.
Fignrle
rigure
5.
6
I - : a : . 9 ! a n a f r - n g e d S u _ - g a - M a ; e : . 1 .C o o d f o r a g i n g
-.
halricar 'or
scn-legel ri. 3oto^r of desL anC
I ta: linrni:r
aan-r:
h- ,-^ . .. i .- ^- .. . - - ' s .
e Lvr
uv:/
Lu>
and thickeis
sylLen, :ast
rL.acrl u o1e- , 2 ^ d
c ^u ,q s
ir Daiau Mesangat.
\d. -ra-'-can.
lJdLct_es
Mahakarit River
Fignrre ? -
Fi$rre
8.
r1r
n"sa at e a . ^ r . l :
T, schiegeJji
Danau Mesangiat, Eas: Kalimanian.
r-r:-1-6- of nesr
: na- !an .
f^racf
i:
6.t^6
F-gure
78
-
Figmre
9.
;4.^-.ii
na
.i:l-r
,r
2
T
.^h7^--1;;
-rs>4_r9aL,
Fignre
10 .
Lab
radts
v
^-
fl^=
ii-
i(alinaniran,
-and
::
:orJs:o1.a san-eEe.i: nesE on
Mesangat,
Danau
Ngibun/Daiau
acres:.
peaL suenp
Easa
79
CONSERVATION,MANAGEMENT AIID FARMING OF
CROCODILESIN CHINA
:.
WanZi-ming
ProgramOficer, CITESMarugemertAuthorityofchina
StateForestryBureau,Beijing,Chin4 100714
Gu Chang-ming
Standing
Manager,AnhuiWldlife conservation
Association
Hefei,Anhui,China230001
WangXao-ming Ph.D
AssociatePrcfessor,
Biolog/ Depadm€n!EasternChinaFormalUniv€rsity
.
Shanghai,Chin42o0062
WangChao-lin
DeputyDirector,AnhuiResearch
Centerfor BreedingChinese
Alligator
Xuanzhou,
Anhui,ChirLa,24203
4
ABSTRACT
TheChinese
Alligator (Alligaar inensis) is restrictedto Chinaandis generally
considered
one oftbe mostendangered
crocodilians
ilt the wodd. Sincethe 1970's,
ChineseGovenmenthaspaidhighattentionon the conservation
of Chinese
Alligator
and carried out a mnge of efective measuresin succession
to stretgthenthe
management
of ChineseAlligator lyith considerableachiwementsbeing nrade.
However,thewild populationof Chindse
Alligatoris still onthevergeofextinctionand
it urgeltly needsmuch concernsfrom national and intemationalcooservalion
corununity.With the fast development
of nationaleconomy,the activitiesrelatedto
impod and export, falming maoufactureand utilizationof crocodiliansand their
productsin Chinabecomemoreandrnbrefrequently.It is ofgreat significance4or
the
protectionof global crocodiliansto enhancethe conservation
and managemedof
crocodiles
in China.
INTRODUCTION
Chinalocatesin the eastempartofAsia andwestembankofPacificOceanwith a
total landareaof 9,600,000squarekilometer.It is a countrywith both coastlineatd
landborder,wh.ichare 18,000kilometeralld 20,000kilometerin lengthrespectively,
15 cou!|tries(e.9.
Vi€tnam)with 6 countries(e.g.
.neighboring
Japan)to its esstand
southeast
acrossthesea.
Chinais dividedinto 33 provincas,
autonomous
regions,municipalities
anrlspecial
administrative
region.Accordingto the censusin 1994,the populationof Chinais
80
L1985billion(excluding
thepopulation
ofHongkong).
With vast territory and diversifiednatural ervhonment,China is one of the
countriesin the world with the mostdiversevarietiesof wildlife resources.
Thereare
6,347speciesof vertebratqaccountingfor over 14%ofthe world tolal, and 32,800
speciesof higherplanl taking up over 12%of the world tolal. Aftong the wildlife
species
listedin theappendixes
ofCITES, 1,700rve.efoundin China.
CROCODILESIN CHINA
Thereare three crocodilianspeciesever known to be occunedin China.The
porons) and the MalayanFalseGhz;al(Tontistona
SaltwaterCrocodile(Crocodyhc
rcregr??)oncelived in southcoastregionofchina. However,Both ofthem havenot
beenfoundin Chinasince1922.Onlythe ChineseAlligatorhasforiunatelysurvivedto
now. Since1993,many speciesof crocodilianssuchas Nile Crocndile(Crocodllus
,i/olicus), SiameseCrocodlle(Crocodylls
sian?rr,t7s),
MssissippiA)ligator(Alligator
misisspiensis)and Saltwiter Crocodilehavebeenintroducedor re-introducedinto
Chinafor fafming,educalionor tourisn purpose.
STATUSOF CEINESEALLIGATOR
i . DISTRIBT]TION
The ChineseAlligator is lhe most endangerdol the world's 23 speciesof
(Groombridge,l982;
crocodillians
Thorbjarnarson,
1992). Thespecies
is a r€latively
smallcrocodilianwith a maximumlengthof approximately
2.5 m (WangC.L., pers.
observation
) .ln Chin4localpeopleusesthena|neYangziE ( meansYangzialligator)
or Tu Long ( meansmuddydragon) to designate
th€ species.
Thelocalnameindicates
that the alligatorwas onc€widespreadalongthe Iower Yangziriver valley. It was
recordedin the allcientChinesebooksthat the Chines€Allicator distributeddenselv
overthemiddleandlowerreaches
ofthe YanglziRiverin thJllth century.
Howeveri
with the dramaticclimaticchangeandthe increase
ofthe humanpopulatioqthe range
ofchineseAlligatorwassharplyshrankto thelowerreaches
ofthe YangtziRiverin the
l9thcentury.
From the beginningof this century to 1960's, due to lake drainagg land
reclamation,
useof farm chemicalsand exc€ssive
captureand killing the habitatsof
ChineseAlligatorhadbeendestroyedvery seriously,resultingthat the populationsize
declinedyear by year and its range continuouslydecreased.The investigation
conducted
in the 1950'sindicatedthat irs rangehadbeenshrunkto theareaofjunclion
ofAnhui, ZhejiangandJiangxiprovinces.The surveysin the 1970'sandearly 1980's
documented
anevengreatershrinkingofthe rangewilhiDthethreeprovinces.In recent
years,the wild ChineseAlligator hasnot tracein Jiangxiprovinceand hardlyto be
found in Zhejiangprovince.It seemsthat the renainingwild populationis almost
confinedto the countiesofJingxian,Nanling,Xuanzhou,Langxiand cuaDgdein the
southemarq of Anhui Provinceand sporadicallydistributesin the smal!inigation
pondsandreservoirs.In addition,smallnumberandsitesofchinesealligatorare also
reportedas beingfound. in Wuhu and Ningguocounties.In lowlandhabitatnonh
towardsthe Yangziriver smallalligatorsare still reportedin Maanshsnand Dangtu
in 1995,anadultmalealligator
counties
ofAnhuiprovince.
Forexample,
wasfoundin
(see
villageofMaanshan figurel) .
8l
DistribrtioD of ChlneseAlligatorln Anhrd province.
Chha
'\-
t
\!-
1 1 5 .E
+34.x i\
''
()
\ ---\
"1
\--t-
\
\*-
,l
t/
'
:'\.,
t , , - , - - r t - .-!.:\.
1;/'
''-'-r;.S'.1?
- - i ..:\-..,,,',P."'
"'-tf-:
+30' x
t15' E
t"
82
In Zhejiangprovincq a smallnumberof alligatorsremainin Yinjiabianvillageof
Changxing
county. Thevillagebecame
a alligalorreseFein 1979.In August1982,on€
maleandonefemalealligatorwerecapturediiom this villageandsentto the rese e.
As no surveyin the reserve,we do not knowthat how manyindividualsremainin the
6eld ahhoughthe habitatis very nic€to allig.tor. Huanget al ( 1987) reportedthat
alligatorswerecapturedh Huzhouand Anji countiesfrom the 1970'sto 1980's,but
now no reportsof alligatorsare from the area.fie Changxingforest bureaustaff
guessed
thealligatorshaderdrpatedin theareaIn fact , mostalligatorsarefoundin agricuhuralfield or in isolatedreservoirsin
tree farm, The tkee principalhabitattypes are riv€rine and swampyarcas,lowelevationagriculturalvillages5
andagriculturalandteafalm villagesup to 100mabove
(
andHuang,
l 984) .
sealevel Watanable
2.ABIJNDANCE
Alligatorsareextremelysecretiveandhardto count.Nght spotlightcountsreved
a smallnumber,but manymaybe hiddenin densandnot visible.Someofthe best
that live aroundthe alligator
informationcurently avalablecom€sfrom localresidents
ponds.Chen Bihui estimated300-500 slligatorsremainedin th€ Arhui National
AlligatorNatureReserve
basedon suweywith Dr. watanablein l98l (Anon.,
Chinese
weremadein ANCANI, Zhou ( 1997)
l 99l ) . Fromthento now,five investigations
presented these results: wild population number was estimated 378-421
individuals,40T-463
individuals,690-740(includingi50 alligatorsreleasedliom the
individlalsand667-740
individuals
in 1985,1987, 1990,
breeding
center),674-747
1992 aad 1994,respectively.In 1997,the ANCANR estimaledthat the total wild
populationwithintheReservewasdecrqsedto about400animals.However,thercare
no firm data oll the statusof the wild population,for example,their ag€sand sex
( Thorbjamarson,
work for confirmethese
1992) .Weneedto funherandsystematic
population
estimates.
ln our view,the marnfactorsled to decliningof theremainingwild populalionare
asfollows.
l- Lossofhabitats.
The ChineseAlligator lives in one ofthe mosthumandensearea.From the late
l6th centuryto the early20t! century therewasa largemigrationof peoplefromthe
and
north into the lowland Yangzi r€ion (Huang,l982;Chen,l990,Thorbjamarson
Wang,submittedto Ortr<) , andmanyalligatorhabitatshavebeendevelopedasthe
agriculturalland.In fact, theseareasare norvundercultivalion(Watanable,l982)that
Today,habitatis stillbeinglost.Fromthe 1950'sto the 1980's,it wasestimated
lhetotal areaof lakesin Chinawasreducedby I I %(Scott,I 989).Thereserveconsists
of smallpondssetin a natrix of valleyscultivatedwith a wriety of crops,mosdyrice.
In a few areas,protectedsitesconsistof smallreservoirin low hillscover€dby pineand
tea plantations.The land-useright within the ANCANR doesn't belong to the
to
management
authorityof ANCANR. Suchsituationshavebroughtgleat pressures
work of wild populalionof chineseAlliSator.
the conservationand management
Thoughmanyofthe alligator'sformerhabitats,whichcanbe usedfor reintroduction,
83
havebeendevelopedto establishthe factoriesandminesor developedinto fam and,
ANCANR is unableto stop those activities.From the viewpoinl of the local
govemments,
the first problemis to stronglydeveloptheireconomysothat the people
areableto makea goodlivingassoonaspossible.
Irom theviewpointofANCANR, it
is impossibleto irnrnigratethe local people(ov€r I million)to other places,and it is
unrealisticto askthelocaigovemments
stoppingtheirdeveloping
activitiesl}r'ithoutany
compensation.
In a[ areas,the pdncipalcontradictionbetweenhumanbenefitand
alligatorconservation
is increasing
because
ofhabitatloss.
2. Thelowinitiativ€
oflocalpeople
onconsewation
.
Thehabitsofpreying on the domesticpoultryandburrowingthe damsandbanks
of rivers,pondsandreservoirsmakethelocalpeopleconsidering
the ChineseAtligator
asvermin.Theydo not like to seeits populationincreasing
andits te.ritory expanding
to their productivelands.ln addition,the fact that the local peoplecan not get the
economicbenefitsfiom theconservation
ofchineseAlligatoralsohampers
tle smooth
implementation
of theconservation
program
andmanagement
3. Habitatsdestruction.
The lo$s of naturalvegetationthroughouteastemChinahas also exacerbated
periodsofdrought andflooding.Floodanddroughtforcealligatorsto moveoverland
wheretheyeasilycap$redor killed ( Chen,1990) .In dry werther,thefamers always
usethe waterof somepondsu,her€the wild individualsinhabitto irrigatetheir crops.
Thisundoubtedly
wili dafiagethe survivingenvirofinentof alligator,andevellrun out
of their food animais.For example,only about 20 individualsremained,and 80
individualswerediedir Shumingvillageoflangxi countybecaus€
ofdrought in 1987
(Zhov, 1997) .Thealligatorswerenot toleratedby localpeoplebecause
theypreyon
(for
domesticanimals. example
ducks) andtheirbunowinginterfereswith thecomplex
watercontrolstrrcturesthat arevital for ricecultivation.
pollution.
4. Envirooment
Most ofrivers, ponds,reservoiNandlakesarepollutedby the fastdevelopment
of
the industry.Such pollution and the wide use of fertilizer and insecticidein the
countrysideare detrimentalnot only to the reproduclionand survivalof Chinese
Alligator,but alsoto its foodanimals.In additior!sincethesnailfevereveroccuredin
southemAnhuiProvince,thechemicalmatterwhichwasused
to kill the snailsalsopollutedthesurvivalofchineseAlligaror.
5. Financialdifficulty.
Due to Iackingoffunds, lhe reserveauthorityis unableto carryfout conservation
programssuchasmonitoringandreintroduct;on.
ThefuDdsallocaledby thecentraland
provincialgovemmentseachyea. are so lirnitedthat they are not enoughfor the
nomallyruDning
ofthe reserve.
LEGISLATION
Chinaacceded
to theConventionon IntemationalTradein Endangered
Speciesof
Wild FaunaandFloral(CIIES) on April 8, 1981andChineseAll;gatoris on Appendix
I oftheCITESat thetimeChinaacceded.
84
E*lt^,n 1972,the ChineseAlligarorwas lisled as classI prorectedan;mals
by
^,.
Lnrneseuovernrrent.AJlea{ards. it was listedas classI specialprotecred
animals
under the Law ofWitd Animalsprotection ofthe peopt"," n"p"Ufi"
o'f Crun" g.;ji;ro
Mgrch 1989. In additior\ the exotic .nimals spec;estisted in Cifei
:fect 9.n _l
AppendixI and AppendixII are ajso includedin the list of China,,
,p..;ut o,ot."tf
wild animalsin I99l by rheMinistryof Forestryb**",
i. S"; f;;J;;;;;
""nr"
rrD, ,n accordance
wjth the law. ln otherword. all the crocodile
speciesimp;ned -tf,!
inro
China are managedas state special protecrealanimals
offiJ lu
conse.vatrondepaiments at various levelsin Chna
"na'"ont
CROCODILE FARMING IN CHINA
In China, it may be permittedto raise the native or exotic crocodiles
!f a farm has
. .
farmins
rechniques
andenoush
tundsbecause
chinalas aaoprea
lid:llllj *onorny
"1tr*. poticyandrhegovernmenls
can
notinrerfere
rheoperations
of a
lfl"l1{"t
rarm ll,rts actrvrtres
with
sar'sq,
the requirements
of internationalconventionsand
oomestrclaws At present.nearly 60 operationsare involved in
lhe farminc of
crocoo es wlth a totatstockofabour I4.000individualsMajority
of lhemis locat;d in
the provinces of sourh and cenrral China. Most of the
ar"
'Crocodile
Chinese Alligator, Siamese Crocodile, Saltwarer
"ipriLfraa
"."oaifo
anJ Nile
Crocodile Accordingto our anallze,lhere is a trend lhar more and more
fafins in
(tuna wtt engagein farmingofexotic crocodile
species
The farmingof ChineseAlligatorstanedar 1929.ln oder to prevenr
rhe Chinese
,,..
/xflgaror.rromextroctron
and protecrthemby captive_bred
method,the firsr crocodile
,jTl
-'.l"i*lh. C:nterforBreeding
Chinese
AJiigaror
(ARCBCA),
wasserupin
f
xuanzhou
cry byAnhuiProvincial
Govemment.
Since1993.
several
zoos,farmsand
tounsmcompanies
have€ngaged
in raising
exoticcrocodile
species
for theexhibition
or
cornmerctal
purposes.
Sofar,it isonlyone.
Crocodilefarmin China,ARCBCA whichhasregistered
at theCITESSecretariat
asa commercial
captivebreedingoperation.
Themainspeciesdomesticated
in Chinaareasfollows.
I. CHINESEALLIGATOR
Nearly50unilsareinvolved
in farmingofChinese
Alligatorwirha totalstockover
^ ^^
6.uuuanrmats
rnChjnaManya lot havesucceeded
in breedingARCBCAis thelargest
'fi,"
oneandZhejiang.
Yinjiabian
Chinese
AlligarorFarm(ZyCAi
) i. frrg", o". ioo.
rormerhasa stockover7.000alligators
andthejatrerhasa stockoimore than200.
Aho$ ail ofthe originalstocksofotherfarms,zoos,gardens
andresearch
centers
in
Chinacomefrom thosetwo farms,especially
i?omtheARCBCA.
I. I. ARCBCA
Thisfarmis situared
withinlheANCANR lr wasesrabl;shed
in 1979.soeaificalv
fortreventingChinese
Alligatorbecoming
exrinction
rtrrougn
farrning
oianj r"searci
on rr rt wasa Jorntprojectbetween
theSFBandAPFD.andmainlymanaged
by the
APFDTwo hundredandtwelveheadsoflive alligatorswerecollectedfrom the wild
as
the foundation
stockby ARCBCAar the time of its €stablishment.
It succeed;;
a5
produciogFl generationin 1982 a d F2 genetatjonin 1988.At present,ARCBCA
covers an ar€a of IOOhectarewith 3 big and 2 small breeding Ponds,more than 10
rearing ponds, an incubation building, a hatchling care bdlding and a hibemation
building.ln order to collect tunds to maintah itself, ARCBCA has allocatedand
transferred714 'ndividualsto 42 zoos, farms, gardensand researchcenters,and oPened
itseifto public for $ldlife education and tourism. The data it Table I showsthe total
egg production (Fl only) and the fertilily and hatching rate of animals incubated
through to hatching. The production ofF2 generationeggsis summarizedon Table 2.
Tabl.l. Reordsof Cnin s. Allisalor.!g nrodlcdon,f.nilily endhatchi.gBcs atARCBCA
Fenility R le(yd
Tolal Eggs
224
1982 l 0
1 9 8 3 t2
19E4 20
1 9 8 5 30
1986 29
1987 37
88.9
90.4
58.?
a3.l
409
26.9
90.5
90.1
90.4
E2.0
84.0
92.4
91.9
,5.0
955
28.0
29.0
2E.0
92.\
94,0
942
27.7
95.4
E5_l
90t
80.0
1045
t219
1990
65.6
22.0
25.0
601
34
Hatching
501
264
1988
1989
ClurchSizo
22,4
t992 4 2
t993
1145
25.7
27.3
86.2
90.2
9t.0
tza6
24.7
85.1
90_5
1994
69
1659
24.0
85.2
92.3
1995
45
987
21.9
9t.2
9t,I
I996
6l
1440
22,9
92.3
85.0
1997
90
z53l
28.1
E9.8
90.4
634
t6629
26.2
l99l
35
Table2. The F2 Clt.csc auigaor egs prcduction,fenility andhlching ratesat ARCBCA.
ToblEggs
clulcl si?,
l98E
25
1969
t990
1991
'1992
143
109
219
l9t3
l0
1995
t996
t2
30
22
40
1991
62
Toral
185
't994
Hatching
r€dility
Rare(7o) Rare(%o)
96.0
27.3
49.7
42.6
44,9
76.1
7t.4
70.2
86.6
24_3
9t.2
?64
351
709
540
26.4
29.4
24.5
90.d
85.1
46,7
919
23.0
26.0
73.4
23.6
l6t0
4613
24.9
86
88.0
42.0
25
2a_6
73_4
86.0
47.2
81.9
After twenty years'developments,ARCBCA not only haspossessedthe capability
of annuajly producing thousandsof hatchlings and satisryingwith the domestic and
intemational demands for live Chinese Alligator, but also can provide enough
individualsfor tuturereintroduction.
Horever , ARCBCA still facesmanydifliculties:As the tanningt€chniques
ofthe
skin of ChineseAlligator have not been developed , ARCBCA is unable to collect
enoughftnds from the commercial
util;zationofthe captivebredalligatorsto maintrin
its operatior and carry out the reintroduction program; thousandsofannual hatchlings
havebecomea hea\ryburdenandbroughigreatpressures
to ARCBCA;dueto financial
difiicultiesandlackingof habitats,theyare unableto retumtheircaptive-bred
alligators
to the wild to releasetheir burden.SuchproblemshavemadeARCBCA beingin hobble
where they can not further developtheir captive breedingstock and retum the alligator
to the wild. In a word, they are in urgent need offinancial and techdcal supportsiiom
the intemational community for exparding their farming scalq tanning alligator skins,
implementingreintroduction ard monitoring programs.
1.2zycr',I
ZYCAF wassetup by the villagersat YinjiabianVillagein ChangxingCountyin
1979.Its sizeis 0.69hectare
a buildingfor accommodat'on
lJr'ith
andhibemation,
2
pondsandseveral
breeding
misingponds.Theoriginalstockwas ll wild adults,of
which8 adultdiedbefore1982.In 1984,oneolthetwo adultfemales
began
to breedin
captivity.In 1997,theF2generationwasbredat ihe farmsuccessfully.
In general,
ZYCAFadoptsa methodolnaturebreed;ng
thatis different
fromthat
just liketheirnature
;n ARCBCA.Theeggsarehatched
in the aliigator's
own nests
environment.
ln addition,ZYCAI feed alligatorswith a kind of ball-shaped
fodder
whichis cheaperandbetterthanfish andfrog andtheyfind out thatthe growthrateof
thealligatorswho feedon the abovefoddercanincrease
from5.22cm to I 6-I I cm per
year.Thisresearch
resultwill providethe scientificbasisfor reducingtbeirfood costs.
ZYCAI has draffeda reintroductionprogramaims at re-establishing
a wild
populationat ZhejiangChangxingChineseAlfigatorNatureReserve(ZCCANR),
but
we areworry aboutthat ifthey cancollectenoughfundsto implement
it.
2. SIAMESECROCODILE
Threeoperations
are involvedin raisingof Siamese
Crocodile.
Ajl the original
fromThailand
stockswereimported
undertheauthorization
oICITESManagement
of
China.Amongofthem,FujianFuzhouAofengCrocodile
Parkhasimported1320iive
individuals
in 1998,Heilongjiang
XnA Crocod;le
Farmhas;mponed300 in 1998,
WildlifeSafar;Co.,Ltd. imported
1,000in 1997andwill
Guangdong
PanluXangiiang
import3,505in 1998.
3. NILE CROCODILE
AlligatorFarming
HubeiGuangshui
YinhuaMississippi
anddevelopmenl
Co.,Ltd.
hasbeenapproved
by CITESManagement
Authorityof Chinato inport 2,500
fromSouthAfricain i998.
hatchlinss
ofN;leCrocodile
a7
4, SALTWATERCROCODILE
Six unitshaveb€eninvolvedin farmingof Saltwater
Crocodile
since1993.The
total odginal stock is morethan I,OO0anirnals.Amongof them,Shenzhen
Wildlif€
Safariimported160 individualsftom Thailandin 1993, HainanDongsharhuWild
Animal Gardenimported60 Fom Malaysia,GuangdongZhuhaiBaitenghuTourism
DevelopmentCompanyimported100 individualstiom Malaysia,Guangdonglanyu
XanejiangvildlifeSafariCo.,Ltd. imported
260fromThailand
in 1997,cu;gdo;g
DongguanTianbaoC-rocod;le
FarmimportedI 70 from Singapore
in I 997,Guanldon!
PanluXangiiangWldlife SafariCo.,Ltd. hasimported22 fromMataysiain 1998an;
FujianFuzhouAofengCrocoditeParkhasimported| 80 fromThaiiandin I 998
5 MISSISSPPI
AILIGATOR
HubeiHonghuBohuaChineseSoftshellTurrteFarmCo., Ltd. imDorted50 liv€
Mississippi
Alligators
intoChinafromUnitedStates
ofAmerican
in I996andintended
to importmorethanI,OOO
in thenearfuture.
REGULATION OF TRADE
According
to theLaw of Wild Animalprotection,
huntingandhlling of classI
statespecialprotectedanimalsis prohibitedexceptfor thepurposeofscientificresearch,
tamingand breedingandexhibition,whena specialhuntingpermitmustbe obtained
from the SFB. Hunting and killing of ciassII state specialprotectedanimalsis
p.ohibited except a specialhunting permit has been issued by the provincial
cons€rvationagency.Ove.rthe past ten years,no live ChineseAlligator has been
allowed collected from the wild. The domestictrade, transport;tion, farming,
manufacturing
andutilizationofall thecrocodilianspecies
mustattachwith therelevaii
permitsor obtainthe authoriationdocumentfrom the SFB or the provincial
consewalion
agencies
Chinaisa pan) to rheCITESandthesripularjons
ofilTES are
appliedto the importandexponof anykind of crocodiljan
specimens
in China.In
addition,Chinaadoptsa morestrictmeasure
whichimportofCITES AppendixII lisred
s_pecies
shouldako applyto thepeople'sRepublicof ChinaEndangered
Sp_ecias
of
Wild Fauna-and
Flora IrnporrandExpon AdminiskariveOfiice (CITESMan;gement
AuthorityofChina)for animportpermit.
MANUFACTURING OF CROCODILE PRODUCTS
Thereare severalmanufacturers
involvedin importingcrocodilel€atherand reexportingits productssuchas wallet,watchbelt, handbagandshoesthat madefrom
suchleather
in southChina
TRADE OF CROCODILE
Thedomestic
tradeofcrocodiles
andtheirproducts
is limited.Mostofthe tradeis
confinedto the live individualandfrozenmeat.As mentionedabovqabout840 live
ChineseAlligatorshavebeensoldto around45 unjtsby the ARCBCAandZYCAL
To thealligator
meat,onlytworestaurants
werepermitted
to sellthefoodsmadeofthe
me3tolchineseAlligarorliom May 1998by SFB.Until noq th€ a igatorskinhasnot
beendeveloped
asacommodity
andnoskinor itsproducts
havebeenputintomarkets.
Theintemalional
tradeonlivecrocodile,
crocodile
meat,leatherand
itsDroducts
is
in a largenumberAs we menrioned
above.over9,500live crocodiles
havebeen
imported
or areintended
to importintoChina.From1997to present,
34,450kilograms
88
*ro#*u$**ruu
ilut#lf""ll#,;.'.u;Hfr
n3,q.r;ru,'",
ffi'ffi--##$#
;,.,1:".rHT,TRdffi
;:,#pii"il.1JtT.*,"1":^;?1"
I. ANCANR
j:.#tH
-],:ff"i: :T,1,ill,i:ffl
;;#fs;:t"ti;i::i;,}",
",:
sffqrj.
[##;"rn"*,
rufi,*;:"';::
;;-tfru
nl***;N*tl**t'*:*.*.,ru*
$;,,-'**i*l***,,,
fr-d:$fr
iilHhiffi
;{H{fr1:qgT:triffi
[ltifiin!ffifi+i;
89
FiSurel. Ther.cordsof rcprodlcrion
ol d. Fit'3Chir.e AatEalorin ANCANR
I
Th€ stalls of the w'ld Chinese
84858687888990929495 969?
-:;t'-a-ihs
Durber df lhe ha!.htjnrs
iiBurc 2. Therecotdsoicrplil. ircu&red,alchlincsflon rh! witdeC$ collccred
Thestatus of th€ wild Chinese
Alligato/s captivebreeding
EroLr !{r
1987
l9E9
1990
I c.p&.
i.rcthr
O,.r!a
t991
.c rh' ,'obcr.d
.h..
Althoughthe wild alligators
esper:ally
that in specialprotected
siteshavebeen
protect€dby ANCAN& thepopuiatiordoesr'ti.creasesignificantlyandit is facingthe
90
trend of decreasingor exiinction. Thus, expanding special protected areas,
.ehabilitating
habitatsand carryingout the reintroductionand restockingprogramof
ChineseAlligatorin the reserveis ofgreat urgency.
2. ZCCANR
ZCCANR was set p in 1982,locatesin YinjiabianVillage.ChangxingCounty,
ZfiejiangProvince Its s;zeis 122 heciare,including0.69bafor the breedingcenter
where is 140 individuals.ZCCANR is funded by the locai people and Zhejiang
ProvincialForestD,
Department.
ZYCAF is situaledwithin ZCCANR and coordinatesits work. However. no
alligatorhasbeenfound living within the reservesince1982.Accordingto irs plan,
ZCCANR ll useits captive-bred
individualsto restockits wild population.The main
problemfacedby ZCCANRis still the flnancialdifficulty.In our view,it will be relative
easyto implemeotthe restockingprogramin ZYCAI becauseol the high initiatives
heldby the localvillagers.
Consideredthe circumstances
of thesereserves,one of key factorsthat may
determinethe abilityof alligatorsto survivein theseareasis the presence
of islands.
Smallislandsprovidea terrestrialretreatthatbuffersthealligato.sto somedegreefrom
humanimpacts.It is very necessary
andimportance
to reconvertagiculturalareasback
into alligatorhabitat.lnorderto resolvetheseproblerns,
furtherstudieson the statusof
alligatoris requiredto establishberterconservalion
strategy.It is very usefulto make
the international
cooperationon the scientificprogramsuchas WCS andus will make
systematic
investigations
of populationecologyof Chinesealligator.The projectwill
addressthe currentstatusanddistribut'onofthe wild populations
andidendrysuitable
alligatorhabitattha! couldbe usedin reintroducr;on
or restockingprograms,and land
useby GIS . Theseirformationarebas;callyand necessary
for alligatorcorservation.
Dr. John Tho.bjarnsonwill presentour researcbplan in detail on behalfof Eastern
China Fornal University,Anhui ProvinceDepartmentof Forestryand WCS. In
addit;on,reservesare not funclionedvery well becauseof lack financialsupportand
tmined workers,and i is very d;flcult to resolvethe cortradictionbetweenwild
populalionand the economicbenefitsofthe peoplefarmingandagriculturallandthat
surroundsand encroaches
on the alligatorhabitatbecauseof no enoughfinancial
suppofi . We bope that internationalorganizationwill providefinancialsuppo'1for
CHnesealligatorconservation
RESEARCH
Research
on ChineseAlligatorin Chinahasbeendon€lor severaldecades
by many
scientists
andinstitutionsanda greatdealofachievements
havebeenmadein the fields
olhistoricaldistribution.physiology,morphology,anatomy,ecology,captivebreeding,
nulrition, diseases,conservationand management.ARCBCA and Anhui Formal
Universityareihe mainresearch
institutions
involvingin studyingthe alligator.
the dangerorN
situationfacedby the w;ld populationofChineseAlligator,
Considering
ajoint suNeyprogramamongWCS, APDF andEasternChinaFormalUniversityhas
beenapprov€dby SFBin 1998andwill be conductedfrom thisyear.
TRAINING
Ten yearsago, a traininSdelegationorganizedby SFB, APFD, Anhui Formal
9I
University and ARCBCA vidted Thaiiand and accepted training on farming of
at the Samutprakan
CrocodileFarm andZoo Co., Ltd. In 1997,another
crocodilians
training delegationorganizedby SFB, A?FD and ARCBCA was invited by Dr. Webb
and attended the training course on conservation, managementand farming of
crocodilians
ar hisWildlifeManagefientIntemational
in Darwin,Australia.Meanwbile,
gavethe shontrainingcourse!o localresearcher
D.. JohnThorjarnarson
ofANCANR,
and will continueto give a threesweeksoftraining coursein July and August 1998.
This year, we have beeninvited1o attendthis meetingfor exchangingexperiences.
Mr .wan Ziming w;ll be loundedto visit Thailandfor leamingon the conseMtion ,
management
and farmingofcrocodiieafterthe 14thWorkingMeetingofCSG. Such
trainingand visits havehelpedor will assistCh;naa lot in its effort to conserveand
developChines€Alligator.
DISCUSSIONS
Through 20 years hard work, a great deal of achievementshas been rnade.The
people conservation awarenesshas been greatly raised , the illegal casesreiated to
poaching of wild Alligator have almost vanished,the farming t€chniquesof Chinese
Alligatorhavebeensuccessfully
developed,
the captivestockofchinese Alligatorhas
inc.eased
to about8,000,the crocodil€fams havethe capabilityofproducingat least
2,000 hatchlingsof ChineseA.lligatoreachyear and more and more farrns,zoosand
iourismcorporarions
areinterested
in farmingofcrocodilians.
However,theresdll existmanydifllcultiesand problems.The wild populationof
ChineseAlligatorhasbegunto declineagain, its naturerangehasa trendofgradually
decreasing,the local people doesn't like to protect the wild population,the
consefvationagenciesare lacking of surveyingand monitoring techniquesand
equipmentand unabieto control the lands,water and foods of the majorityof the
habitat,the skin tanningtechniqueshave not been successfully
developedand the
crocodilelarms can not collect funds from comnercialutiiizationof captive-bred
ofchirese Ailigatorto supportthe conservation
specimens
ofthe wild populationand
people
to compensate
to the local
for their losswhich are causedby the wild Chinese
Alligator,aodthe smugglingofcrocodilesandtheir productshaven'tbeenthoroughly
controlled.
Based on above situations,in order to enhancecrocodilianconservationand
management
in Chira,the followingactionsarebe;ngconsidered
to take
l. Further enhancethe awarenessof conservationand strongly encouragethe local
peopleinvolvingin the conse.vat;on
programoaChinese
Alligalor.
Tbe conservation
courcewill be heldio variousschoolsso that it canmakemore
the imponanceofcorsewationthroughthe ANCANR
andmorepeopleunderstanding
instruction.In additionto that, it is importantto add valueon alligator.In casethe
alligatorhasbeendevelopedas a commoditywith relativehighcommercialvalue,the
peoplewill activelyand conscienliously
protectanddevelopthe alligatorslivedin thei.
Iands.iust
like prolectingtheirowr property.At the sametimq it will alsoundoubtedly
attracta great deal of farmersto participatein the conservationprogramssuchas
farming,resrockingand reintroducingof al gator and bringsfinancialbenefitto the
peopleconcemed.In our view,only by relyingon tbe localpeoplecanwe tully protect
anddeveloplhe wild populat;on.So, oncethe condilionis ripe,the villagerswithinthe
92
reservewill be encou.aged
to engagein aboveactivit;esby the conserv?tion
agencies.
2. Preventthe exoticcrocodilians
from escapjng
to the wild.
Many crocodileexpertsare wonling about that jt will be detimental to the
survivalofnative ChineseAlligatorifthe exoticspeciesofcrocodiliansescap;ng
from
the farm to the wild. We think that tHs may be a problem.But it seemseasyto solve
throughstrengthening
the farmingmanagement,
limit;ng or forb'ddingthe farming
activitiesin the naturerangeofChineseAlligarorandconlrollingthe scaleofcrocod;le
farmingindustry As everyoneknow, due to the cold weathercondition.the exotic
crocodiiianspeciesexceptthe MississippiAlligator may not be ableto survivein the
wild at thenaturerangeofChineseAlligator In addition,all ofcrocod;lians
speciesare
managedas China'sspecialprotectedaninalsand the actidtiesrelatedto crocodile
farmingare well controlledunderthe conservation
agenciesat variouslevel Even if
theyescapeto the wild, the farmerhasrhelegalresponsibility
to capturethemfrom the
wild in accordance
with the relatedprovisionsofthe Wild AnimalprotectionLaw.
3. Funherstfengtben
the management
ofimpod andexpo( ofcrocodilian.
Thoughsomeillegaicasesofsmugglingofcrocodilianandits producrshavebeen
invesligated
andprosecuted,
therestill existssmuggling
phenomenon
in southChina In
order10crackdown the illegalsmugglingact;vitieson crocodilians,
a specia!national
suNeyon the farmingand utilizationofcrocodiliansand the;r productsorganizedby
CITESManagement
AuthorityofChinawill beconductedby thecons€nationagencies
at variouslevel.Ifa dealeror farmercouldn'tshowrelatedDermitsanddocumentsit
willbeinvesligared
andprosecured
Ourpoticyisrhalonceiihasbeenfound,itwill
be
seriouslyhandledin accordaoce
w;th rhe provisionsof Chineselaws and CITES. In
addition,a reglrlarcommunication
systemis plannedto be setup betweenthe CITES
Management
Authoriry and the Customsto enhancethe exam;narion
of permitsand
imponedandeyported
goodsandrmprove
rhecapabjtirv
ofidenlil,ingwitdanrmats
an;
theirp.oducts.
4. Furlherpromoteandstrengthen
the internalional
cooperation.
The following fields are in urgent needsto be strengthened
by international
cooperation:reintroduction(restocking,surveyingand monitoring)programof the
ChineseAlligator, tannirg alligaror skin program and intemationalmarketingof
alligatorproducts
With the kind help ofDr c.ahane and his colleagues,
Anhui provincialForesrry
Deparrment
hasdrafieda management
prog.amfor conservation
ofChineseAlligator
(seeannexl). We s;ncerelywelcomeeveryoneto d;scussabou!;i and any pragmatic
and working suggestionwould be highly appreciared.
Nevenh€less,it sbould be
emphasized
that suchsolutionnrustfir in with the realitiesoflife in China.Oncethe
programis passedandgel the financialsupportat tbismeeting,it will be
management
implemented
soon.
Due to lackingofthe skin ianningtechniques,
t|e skin ofChineseAlliqatorhave
not fofmeda commod y andlhe alligrrorfarmsare rrnableto collecrfi.rnds
io supoon
prosrums
theconservarion
concerned
Thus.oneofthe urgenttasksar presenr
i; to
deuelop tlre lnnning as well as orher lechnrqucsas soon as possiLlethrough
international
cooperation.
93
CONCLUSION
China.asthe wodd s largestdeveloping
country.is restrictedby its lessadvanced
social. economicand technicaldevelopment.has hundredsof endangeredspecies
awaitingfor ils specialprotection,will be difficultto allocatemorefundsto supponlhe
conservaiion
ofthe wild populationofChineseAlligator.In addit;on,ChineseAlligator
is the commonherirageof all humanbeingsand it aiso ought io be caredby the
internat;onal
communityWe wouldlike to takethis opportunityto invite all olthose
who arereallyconcerned
w'th the conservation
causesofchineseAlligator,including
researchers,conservatiol professionals,farmers, tanners and ;nternational
organizations.
to supportfor andpanicipatein theprogramsmentionedabove.
SinceARCBCA is a open tourist site, we hope rbat it will be built a world
Crocodileexhibitioncenterwith all speciescrocodilians
in the world by exchanging
live
andiheir specimens
wirh d;fferentcountries
crocodil:ans
ACKNOWLEDGMENTS
We would like to thank Dr. GrahanreWebband Mr CharlieManolisfor their
lo0g-termassistance
to us in conservation
ofchinese Alligator.We would especially
l;ke to thankDr JohnThorbjarnarson
and Mr. Uth€nYoungpmpakorn
for providing
tunding ro Mf. Wan Z;ming and Dr wang Xiaonringfor their padicipatein this
meetingAi the sam€time. we would like lo thankWildlife Conservation
Societyfor
it's providingfund;ngto us lorjo;ntly conductingthe su.veyolwild ChineseAlligator,
and Australia-China
Councilfor providingtundingto Mr. WanZimingfor his studying
;n Australia
REFERENCE
Anon | 99I Registration
of the Anhui Research
Centerof ChineseAlligator
Reproduction
for.4//tgdt r.st,?rsir P.oposalCITES.
Chen,B.C..Wang.S.B
andWang,B.Z 1984The endangered
animal Chinese
(lo Chinese).
alligator.Anhuiscienceandtechnologypress,Hefu,Cb;na
Chen,B.C.1990The past and presentsituationofthe ChineseAlligatot.Asiatic
Heryeklot! LdI llcsearch 3: I 29- 136
Chen.B.C.l99l ChineseAlligator pp 361-365ln the Amphibianand Reptilian
FaunaofAnhui . (ed.Chen,B.C
HouseofScienceand Technology.
) .Anhu'Publishing
Hefei,Anhui, China(ln Chinese)
Groombridge,B. i982 Amphibia-Reptilia
Red Data book Part I. Testud;nes.
CrocodiliaandRhynchocephilia
. IUCN , Gland, Switze.land
Huang . C C. 1982 The ecologyof the Chinesealligatorand changesin its
geograplrical
distt;brtion l'k Leednrysof the 5'' r'otkiug of th. I{K'N SS('('ft'Lodil
Srccialn Ct.rtp,Gailresville
, Florida. l2-16 August1980 pp54-62.IUCN. cland
SwitzerlaDd
94
Thorb.jarnarson
. J B. 19S2.CrocodilesAn adion planfor theirconservalion(ed.
By H Messel.F W King andP Ross.)IUCN, cland Switzerland.
Thorbjanrarson
, J.B. andwang,X M. The conservationsrarusof rhe Chinese
alligatorSub'nittedto./. OnYX
Scott.DA. 1989A directoryofAsian welandsIUCN-TheWorld ConseNation
IJion Gland.Switzerland
Watanabe.
M .E. I 982 TheChinesealligator: is farningthe lasthope?J.Orlx I 7(4):
i 7 6 -t 8 l
Watanabe.M.E. AND IIUANG c c 1994Landsatremotesensingimageryas a
tool in defingthe environment
ofthe Chineseaiingator,Alligatorsinensis
Fauval. 216219.
Zhu hong-xing I 997 Observationon wild pop'rlationof A lligabr si'rer.rir .Sichuan
Joumalofzoology. l6(l):40-41(ln Chinese)
Zhou Ying-jian 1997 Analys;s on declhe of wild Alligahr snrcr.rtr poputarion .
SichuanJournalofzoology l6(3):i3?(ln Chinese).
95
ANNEX I
A MANAGEMENTPROGRAMFOR CHINESE
ALLIGATOR IN ANHUI PROVINCE
(Drafts)
r. SPECIESSUBJECTTO MANAGEMENT
CIass:Reptilia
Order:CrocodyJia
Family:Crocodylidae
SpeciesAlligqlor SinerJis(ChineseAlligator)
2. PROPONENT AND SUPERVISORY AUTEORITY
AnhuiProvincialForestryDepartment,
the People'sRepublicofChina
No. 53,WuweiRoad,Hefei,Anhui,China.
Telephone:+86-5
5l -267 5320
+86-551-2661287
+a6-551-2675320
Fax:
3. INTRODUCTION
Aliigatoris currentlyrestricted
to AnhuiProvinceofChinaandis gercrally
Chinese
considered
as oneof the world's most endangered
crocodilians.
Thereare only about
Alligatorslivingin thewild andabout8,000kept in captivityin 1997.
400 Chinese
Chinese
Alligator,alsocalledlanddragon,wasincludedin CategoryI ofthe State
in 1972andlistedin ClassI of StateSpecialprotectedspecies
ProtectedSpecies
under
the Law of Wild AnimalConservation
ofthe People'sRepublicof Chinaenactedin I
March 1989.Capturingand huntingof this speciesis prohibitedexceptfor scientific,
whena specialhuntingpermitmustbe obtaircdfrom the
tamingandbreedingpurposes,
StateForestryBureau(SFB,fo.mer Ministry ofForestry). The farmingand commercial
useof the captive-bred
alligatorsare permitted,whenrelatedpermitsor documents,
such as impo.t and export permit, transportationce.tificate and dealing and using
permit,havebeenobtainedfromthe SFB.
with the provisionsof Law of Wild
This programis developedin accordance
AnimalConservation,
the Regulations
on Management
ofNature Reserves
for Forest
and Wildlife Type and the Rulesfor Implementing
the StateLaw of Wild Animal
in Anhui Province.Its aim is to furtherconserveand developthe wild
Conservation
populationof ChineseAlligatorandits habitatsandactivelysavethis endangered
and
endemic species throughout the Anhui National Chinese Alligator Nature
Reserve(ANCANR).
Prior to this program, the Anhui ResearchCenter for Breeding Chinese
Alligato(ARCBCA)was set up in Xuanzhoucity in 1979and the ANCANR was
establishedin 1982,by SFB. The administrationof ANCANR is coordinatedthrough
ofChineseAlligatorby
havebeenmadein conservation
ARCBCA.Greatachievements
of
of th€ localpeoplewithin ANCANR for conservation
thoseunits.The awareness
ChineseAlligatorhasbeengreatlyraisedandthe illegalcasestelatedto poachingof
of ChineseAlligator
the farmingtechniques
ChineseAlligatorhavealmostvanished;
thecaptivestockofChineseAliigatorin ARCBCAis
developed,
havebeensuccessfuliy
about 8,000 and the ARCBCA has the capabilityof producingof at least 2,000
peryea. .
hatchlings
very
However,the.e still existsmanyproblems.The wild populationincreases
the localpeopleis not
areahasa trendofgraduallydecreasing,
slowly, thedistribution
not
benefitsfrom the
they
can
obtain
positiveto protectthe wild individualsbecause
and
agencies
areIackingof surveying
protectionofChineseAlligator,the conservation
food
water
of
the
the
and
andfacilities,it is unableto control
monitoringtechniques
agenciesbecausethe landsand water belongto the local
habitatsby conservation
of
specimens
on utilizationofcaptive-bred
people(includingtreefarms),thetechniques
developed,ARCBCA can not collect
ChineseAlligator havenot beensuccessfully
of ChineseAlligatorto
specimens
fundsfrom commercialutilizationof captive-bred
to the localpeople
ofthe wild populationandto compensate
supportthe conservation
for their losswhich are causedby the wild ChineseAlligator.The presentprogram
a rangeof strategiesthroughwhich thoseproblemscan be gradually
encompasses
solvedin fiveto nineyears.
4. AIMS AND OBJECTIVES
programis developed
for thepurposeof furtherprotectingofthe
Thismanagement
remainingwild populatioflof ChineseAlligator and its habitats,savingthis most
individualsinto the wild to
speciesthroughreleasingthe captive-bred
endangered
andfurtherraising
the wild populationfollowingIUCN guidelines
restocldre-establish
ofthe localpeoplethroughbringingeconomicbenefitsto
awareness
the conservation
the localpeople.
in five to nineyears:
programseeksto realizethefollowingobjectives
Themanagement
of remainingwild alligatoraod its habitats,enlargeit
the conservation
l. Strengthen
projectl
throughrestocking
severalwild population
the naturehabitatsofalligatorandre-establish
2. Rehabilitate
project;
throughreintroduction
populationthroughranchingproject;
3. Enlargethe re-introducing
on
opportunities
by creatingemployment
awareness
4. Enhancepublicconse.vation
peoplei
Alligatorfor local
of Chinese
farming/reintroducing
the wild population.
andenlarging
on conserving
thematureexperiences
5. Summarize
5. LEGISLATION
Chinais a partyto CITES andthe ChineseAlligatoris on AppendixI of CITES
thisprogram
ofCITES shouldbe followedwhileimplementing
The provisions
rulesand laws relatedto the
All of the existingprovincialand nationalregulations,
conservation
of wildlifeareavailable
to this program.Moreover,anyactivityrelatedto
thek;lling,tradeandcommercial
useof wild individuals
areforbidden.
6. MANAGEMDNT OF TIIE RESTOCK
ANCANR coversfive city and counties.includingXuanzhou,Guangde,Langxi,
JingxianandNanling,with a totai areaof433 squarekilometers.
The usingr;ghtofthe
landsand water surfaceswithin the reservebelongto the local people.The main
habitatsofthe wild alligatora.esmalireservoirs
andponds.No alligatorhasbeenfound
in the riversandiakes.Therearethilteenkey protectedareaswherethewild alligators
concentratein. Each spot has less than 20 wild aliigators.AII of those areasls
monitoredby thestaffofthe reserve.
In order to implementthis program,a surveyon the wild alligatorswill be
conducted.
Whenthe range,number,ageandsexofthe wild alligatorsare clear,the
reservewill selectmorethan20 distributingspotsfor restocking
ofthe wild population.
Accordingto thesurveyresultsandotherrelatedresearch
achievements,
ARCBCAwill
release
captive-bred
adultsintothe abovedistributing
areasto enlargetheexistingwjld
populationIt is recommended
thatthesexratioof I :3(male:female)
in eachspotwould
be appropriate.
Thosespotswill be looked after and monitoredby the staff of the
reserve.
7. MANAGOMENTOF THE REINTRODUCTION
Considering
that the presentdistributingspotsofthe wiid alligatorarelimitedand
the localpeopleshouldobtainbenefitsfrom the protectionofthis endangered
species,
ANCANR must call for the local peopleand relatedstate-owedtree farmsto be
project.The relatedlocalpeopleandtree farmswho
involvedinto this reintroduction
would like to take part in the reintroductionproject shouldprovideponds,foods,
manpowerandothernecessary
facilitiesto thisp.oject.As a compensation
means,the
reservewill providenecessary
techniques
and captive-bred
alligatorsand the Anhui
ProvincialGovernment
will providecertainsumoffunding,to thelocalpeopleandtree
farms.
The spotsusedfor this projectshouldbe selecred
by ANCANR,wherethey are
suitablefor the living of wild alligator.In order to preventtheir escapingand to
facilitatethe management
of the reintroduced
alligatof,the iron net will be erected
aroundthepondsat thefirstyearwhenthe reintroduction
projectconducts.
Therelated
localpeopleand tree farmsshouldsign contractswith the reserveand the contract
shouldmakedef:niteeachother'sobligationsandresponsibilities.
In general,the local
peopleareresponsible
for thecareofthe reintroduc€d
alligato.sandtheirhabitats.The
recommended
sexratioofthe reintroduced
alligatorsis 1:3.Fourindividuals
wili forma
group.About 10-50groupsof captive-bred
alligatorsshor]ldbe released
into selected
pondsand reservoirseveryyear andthe gtoupsreleasedinto one pond or reservoir
should
bedecided
by theconditions
ofthe area.
8. MANAGEMDNTOF TI{E RANCHING
In order to ensurethe reintroduced
populationincreasing
quickly,the ranching
programshouldbe introduced.
Whenthereintroduced
females
lay theireggsin thewild,
the eggs will be collectedand incubatedby ARCBCA in time. ARCBCA witt be
responsible
for the raisingof the hatchlingsuntil they reached3-4 yearsold. Then,
98
releases
someof them into their originalhabitatsor other placesdependingon the
circumstances
of the habitats.The ARCBCA shouldpay additionalfee to the local
peoplefor the eggslaid at their lands.The datarelatedto the nesting,eggs,fertility,
(number,sex),mortality,etc.shouldbe recordedin detailbythe
incubation.
hatchlings
localpeopleandARCBCA.
9. ROLE OF RELATBD ORGANIZATIONS
The ANCANRis responsible
for the communicating
with the localpeopleandtree
farms , signingcontractsof reintroductionprogramwith local peopleand farms,
conductingtechnicalinstructionand administrationof local people and farms,
trendof the wild populationand compilingthe annually
monitoringthe development
reporton implementing
ofthis program
The ARCBCA is in chargeof providingcaptive-bred
aliigatorsto the ANCANR
projects,incubatingeggsand raisinghatchlings
for restockingand reintroducing
and
juvenilesfrom ranchingproject, organizing
andholdingtrainingseminars
on farmingof
alligatorfor local peopleand tree farmsand developingthe techniques
on usingof
captive-bred
alligator.
The APFD is in chargeofcoordinatingthe relationship
betlveenthe reserveandlocal
governments,
drawingup or approvingthe programson protectionandutilizationof
ChineseAlligato., collectingfunding from intemationalcommunityand related
governmentagenciesand grganizations
and providingfunds for implementing
this
program.To someextent,the possibilityof successof this programwill be mainly
depended
on the financialsupponsAomthe international
community.
IO.EDUCATIONAND RESEARCH
In general,the publicityandeducationwork on conse.vation
ofChineseAlligator
over the past20 years.In the future,mostof the
hasbeenmadegreatachievements
publicitywork will be focusedon the alligator'scommercial
valuefor the purposeof
encouraging
local peopleand farms interestedin farmingof alligatorand directly
involvingin thisprogram.Thefinalgoalis to makethemregarding
the aliigatorhabitats
asproductivelandsandto ensurethemgainingeconomicbenefitsfrom thisprogramThe previousresearchmainly focus on the biology, ecologyand farmingof
alligator.The future researchwork shouldbe focusedon the developmentand
application
ofmonitoringtechniques,
reintroducing
techniques,
thebestdensityfor wild
population,commercial
farmingand utilizationcaptive-bred
alligator,raisingup the
rateofnesting.fertilityandhatchingandreducingthemonalityrateofhatchlings.
The foreigncrocodileexpensare encouraged
to involvein this programwith their
progranl,
funds,equipments
andtechniques.
research
I I. MONITORINGAND RBVIBW
wild populationandthe reinroducedstocksandtheirhabitats
All ofthe remaining
If it
shouldbetakencareandmonitoredby the localpeople,treefarmsandthe reserve.
pafi
the radio-tracking
deviceandGIS maybe usedfor monitoring ofthose
is possible,
identirycertainareasas the contractingplacefor its
The
reserve
should
individuals
for the technicalinstructionto the local peopleon
staE Thesestaff are responsible
99
project,designing
thefood typeandamount,
restocking
or reintroducing
rehabilitating,
and
other
relatedworks The staffof
population,
the
eggs
collecting
monitoringon wild
the reserveshouldsubmittheirworkingreportsto the reservet cea year.Thereserve
the work whattheyhavedoneat themiddleofa yearandsubmittheir
mustsummarize
reportto the APFDat the endofa year.
annualimplementing
Whenthis programis completed,the reserveshouldprepareandsubmita repo.t
ofthis programandthe proposalaboutthe futuremanagement
on the impiementation
and the APFD should
andmonitorwork to APFD andrelatedfundingorganizations,
programfor the cotservationof thoserestocked
formulateanotherone management
populations
andtheirhabitatsbasedon the situationat thattirne. The
andreintroduced
and foreign expertsare welcomevisitingAnhui Provinceto
fundingorganizations
ofthis program.
instructandinspecttheimplementation
I2. MARKET FORECASTING
aspets,touristdisplayor intemal
to be internationaltrade
ChineseAlligatorseems
use,suchasfat, oil ,bones.
tradefor meat.skinandpossiblymedicinal
arelocatedan easy
Anotheris tourismbenefit.ARCBCAandthewild populations
provinceis the
Anhui
Very
close
by
in
southern
day'sdrivefrom China'slargestcity.
visitedby hundredsof thousandsof Chineseand
Yellow Mountains,a destination
good
organizedtourismprogramwill generatea lot of
foreigntouristsper year.A
moneyfor ARCBCAaswell asfor localpeople.
100
PEILIPPINE CROCODILECONSERVATION
(Comprehetrrive
Report)
by
GERARDOV. ORTEGA' D.V.M.
INTRODUCTION
Itl 1935,Karl P. Sohmidt,cumor of herpetolos/ of the Field Museum.ofNatual
the rh ippinecrocodilein the islandprovinceof Mndoro'
Hrt".y t;ci;ug;;iscovered
thus,it was namedC/ocaa'fus mindorensis
of the
In 1982, forty leven (47) yerrs after its discovery, Chadel A Ross
500-1000
to-be between
SrnittBonianInstitution estimatedits remainingwild population
t'orced-rt to proposea
$tdch
maturedindividuals. That repon alarmedthe govemment
twJ endangoed species of crocodiles (C
;il,h",
'mifuorensis will halr the rnarch of the
and,C. porosus\ocaunfuryin the country to extinction
was cr€atedwith a
Finally, on August 20, 1987,the CrocodileFar!ftE Institute
thrcugh the Japan
sant-in-aid and technicalcooperationfiom the JapaneseGovernment
ilternationat CooperatiooAgency(ICA) lr hastwo{2) mainobjectives:
and
ofcroaodilesin thePhilippines;
species
tJletwo endangered
l- To cotrserve
well-beingof the local^corununiti:sthrouSh
2. To prcmolethe socio-eoorcmic
-'
inboductionof a suitablecrocodilefarmingtechnology
itl l"u"toprn*t
""a
personnel'
OnMarch4, 1988theproject(CFI)officially openedandhiredits
CEATJ,ENGESAND
SITUATION; CONSERVATTON
PH{r TPPTNE
OPPORTUNIIIES
The Peopl€and the Eovironmert
birds' 233
The Ptrilippinesis rot or y hometo 950 :petie-sanq-sub.s!:ciesof
to 70
home
and240 spe{ies-of reptiles'it is also
of mammals,
,o."io and
a per
"Jtli*i"s
r"ruioti.yof thesepeopleat" livittg b"low the povertv-linewith
riil"i iliitoi"*'
to be
or $i,ssi.ts p€r anrum- Four million people are believed
i"J."
;;;
unernployed.
l0l
With the country'seconomyitr bad shape,manyof the poor, unemployedand
to expandtieir useof
destitut€Filipi[os ar€ forcedad will be forcedby circumstances
peopleare now ensroaching
andwill be encroaching
on the
nsture. As a consequence,
forestlatrdsand wildlife babitts for purposesof livelilood. Theyengageandwill be
engaged
in hunting,illcgaltradeof wildlifeandits by-ptoducts,illegallogging,slashand
bumfanningandcyadde*6 4r"rai1s fisf ing in orderto survive.
non-fiiendlyindustriesare
On the other han4 migplacedand environmentally
thePbilippinesituatiotr. aggravating
Theresultsof thesep€rniciousactivitiesare devastating.Thirty h€ctaresof the
a day).
Philippineforestcoverarebeingdenudedwery thtty fiinutes(or 3,720hectares
of its nangroveforestareb€ingexploit€d
In the plovillceofPalawa!alone,954hectar€s
everyyear. Thenumberof wildlifesp€ciesin kmediatedang€rof extinctionis now 189
is arnongthetop l0
includingthePhilippinedocodiles.Not surprisingb,thePhilippines
in theworld.
ecorystems
hotspotsof mosteodang€ted
the Philippine
Sixtythreeyears(63) ago whenKad P. Schmidtfrst discovered
crocodilein Mndoro, a vsst rumberof Philippinelakes,rivos andmarshlandswerestill
terrningwith crocodiles.Howwer, shortlyafterthe SecondWorldwar 0945), hunting
andpoachingstartedto diminishtheirnumberdueto its valuablehide.
Crocodilesio the Pbilippineshavepoor public image. Theyare beingviewed
in almostall levelsofthe sociEty.LocallyJoownasDrwa'a,theyarebeli€ved
negatively
by ruralfolksto b€ b€are6ofbad tidirgs andin thc leaguewith the darkforc6 of nrtule.
Thustheyarcoftetrrcferredto asasnwangor witches.
appearauce
did not endearthemto the
rraure anddinosaur-like
Tbeiraggressive
h8pless
victimshavereinforced
crocodiles
attackhg
populacc.Reportedcasesofproblem
beli€fofthe ruralFople. Crocodilehunter are€venbeingrevscd and
this superoatural
of a$tlet gr qting-atting alld giftedwith
viswedasextraordimryteings in possession
courageand skill- Theyare very popular8od sdddrediqdividualswhoseslaughterof
serviceto thecommuoi8
heroicactsandaoexernplary
crocodiles
areconsider€d
Crocodil€sare&lsothe mostmalignedard ridiculedanimalsh thePtrilippines.ln
with corupt gove.nment
theFilipinoculture,orocodilesor tultqn aroalwaysassociated
p8tmlrne4
polic€meq
highr"ay
tax andcustomscollectots,
ofhcials,greedybusims$neq
andselfishathletes.Itr gercr8l,conmonFilipinosExeurconc€medandiqditrercntabout
- a vermin.
creatu{gs
theiIfate. In totality,oocodilesareregarded8sus€less
Ch8lleDgcs
Resclrchand Devclopmetra
wasgoping in the darlqthelevelof
Duringtheearlydaysof theprojec! everyone
of
socodilia
biotory, physiologr,anatomysnd
minimal
in
tefms
hrowledgewas very
in termsof capturil& handlingand
patlplos/. Thetecbnicalstaffwere inexperienced
102
husbandry.Therewas no deepunderstardingaboutthe missionaodvision as 1o how the
two objectivesofthe project canbe translatedinto reality.
Crocodile sourcing was another big challorge. Crocodiles 8re scattered in
difercnt parls ofthe archipelagqandthe extent ofits current distributionis not very well
known. Survey qrd trapping activities a.e often hinderedby the prewailhg insurgeaoy
situatio! in the habitatarcas.
The propriety of introducing crocadile fanning in the Philippineswhile many
Filipinos are sutreringfrom the complex social problerns8nd are dying due to protein
deficiencyand malnuffition i8 a very sensitiveissre. An 8ppropriateapFoach must be
carefirllyplannedso asnot to add ine{t to injury.
To summarize,the causesand solutioruto researchanddev€lopmentproblems8tld
challengesare:
PROBLEMS
soLUnoNs
CAUSES
l. Soutdngandacquisition endangarcd
eecics,pesce ApFop.ialr tsapde!'Elol|ient intetNified
andor&r, ttrd hsbitatco!- traFing ocliviti€sandr€goliationl,oaoquite
ofstocf
vclsiotrald drstucliotl
Fivatc crocodilccollcdionin ftvor oflbe
gorgrtlrtrent
giaed Fople's suppott
prior
m
training
acqqisilio!oflt&tlocas 3trdlil,crafirrc,
2. lccbricalblow-how
of iditutionsl lid€ges and
dev€lotrnent
forcigntlalnin8Eatldt clEical cxchangc
re*orehaaddecrvatioar
iDtclsivcidormtiod ard cdrcalionaod
ncgSrivr
3. locirl acc.trability
Frcaption
.onouni.ation @C) in fi-n€dia
cirElrilous
burraucnticinza chargath! pohr ofvicw ofh,rraucrats8!d
{. hlttartcracy
8.i! O.ir !| lport
Strtus rtrd Distribution
. Strtuc
Credylus nindorensis, found only in the Philippines, is the most higbly
endangeredcrocoditianin the world todsy. No large populationi8lflown to exbt in ofle
area. Therc remainonly minor pockas of babitlt itr which C. midorcnsis efists todly,
and none sppearsto be protected. Isformed estimstesield a maximumof 500 animals
held in captivity ard ia the lvild- The wild EiilrEls are scatt€r€din Mindanaoand a few
otber blan& in the SouthernPhilippines. The speciesis ltuted in Appendix I of CITES
and is considercdendangeredby the IUCN - The World Cons€rvalionUnion (Messel et
81.1992,Rossl9E2).
103
. Ililtoricd Dirtributiotr
and
h8sbeenreportedto havethdvedin Northeastem
Ctudylus mindorensis
islands
Mndamo
Jolo'
and
Busuang4
Cent$lLuzor! Samar,MasbatgMndoro,Negos,
(Ross1982)(s€€lrig. 1 ).
. Crrrctrt Distributior
Basedon the acquisitionrecordandinicrrnationgatheredby CFI, C' mindorcnsis
is stiuplesentin the followi4 areas:Mndoro (Naujanl-ake),Mindanao(AgusanMarsh
(DipuyaiRiver),andTuguegano(Fig 2)'
Marsh),Buzuanga
andLiglrasan
In all oftheseareas,MndarBohasthe mostrumb€rof crocodiles(N=227),note
was obtaiaedwhichis indicativeof its degr€eof
tlnt in Mindoroonly one(l) speoirnen
erdaraementin thi; ishnetprovhcewbereit was6rst discovercd(OrtegaandRegoniel
in trke Nauja4OdeotalMndoro'
arenowencroacbing
1993),Ircal resideots
two dv€rs,Dipuyaiad Bqsusng4still containcrocodiles Orc C
In Busuanga,
nindorensisvas 6tgIf. in DipuyaiRiverandseveralothershavebeenobservedby local
residents.A local informafltreportedseeingsone smallcrocodilesfartherupstreamin
River. Two crocodileswe,realso observednearold Busuangaport (1989)
Busuanga
ahhougithesehavenot beeocaught. The upperBusua"g River driesup into isolated
Sto.Niio, whereDipuyaiRivermouthis located,
wateriools locatertinland.Ia Barangay
a C. i dorensiswas caughtin 1989but escsped:"-Itwas estimatedat 2-3 m long'
AnotherC, m dorensiswas Urouefitto CFI on Mey 3q 1991fiom an ares called
to pass
Bogtong.Thecrocodilewascauglrtby the crewofa fishiagboatwbichhappened
Uetie€o t aho islaadand the DipuyaiRiwr. Sigirtingshave also beenreportedin
island(Regoni€tPoltilas et al'
River on the eastemportionof the Buzuanga
Labangan
wasreportedlydisplayedalivein
(northemLuzon)one specimelt
1993): In Tuguegatao
the prouinciairnJseuol(Rami{ezpers com.). Verbal repor! hav€it that -scarceand
isolatedpopulationmaystill be presentin theNorth SisrraMadr€Nah|llalParkh Isabela
MlaD, perscorn.,1995), Cagayarriver system(TugasPerscom.,l995}ihe Maqyan
itdtagi l.taturePark in OccidentalMindoro @iaa pers com., I 992), nog River in
Negroiislarq riguassrMarsh,andin srmll lakesard riversof Mndanao(Ortega1998)'
Theabsenccof reportof siglrtingsin fonnerlylxlown habitatsof C' mindorensis
may indicatetwo things: that its populationis swerelydepl€te4ad tbat it's hardly
noticedor it hasgoneextinc'tah€ady.Althoughlew effortsarcbeing€t(eltedto surv€y
all the knorrnhabitatsof C. minfurensisto drawa morc acouratepictue of its ptesent
state. Two very recetrtsurveysdoaein AgusanMarshitr MildEt|aoyieldedtregative
reflllts, althoughit has b€encodrned duriagthe fust survey(year 1994)that C
was seenon
is iohabitirythe marsh. This was after a live aduhspecimen
mindorerrsis
exhibitin theprovincialcapitolgroundsofAgusal del sur bdore it died.
104
&
o
B
N
f
z.ztE t
K fi isrorical distribution range
\
J.\-
**"TqN,
"\w
r*""'s.fuLly'oi
"*",*.!\L
-b-c
/ud
-}JF
\\^
Y/'
z|rnlorr8rdet srJr
Joe.
1l':ry".u
,..)
\:;
!o
1982)
Iig.1. Historical di,slriburionof C.rflinfur.nsis in the PhiliPPines(Rossaid A1c81€'
l0s
"0
o
a 0
N
1
IffiElYD
a CurrenlDistribulion
.l
r*""'s.$
-b(
/us
"$F
\\^
4
g'\\t*,_-__.-'
G,.4"^\-,!I H.o'^' N.{.--J\
Vn),Y\\;
yr.-'
)// ,.:'-J
V'. ""..S
Y//
Agusarr
o
I'UNDANAo
a N.CoraqgJo
Eig.2. Currenl Distri'u\ion of C.ajn,brensit in rhe PhiliPpines batedon cfI records
106
Srnctuuy Identificrtion rrd E tablishment
hasalwaysbeen
Sincetheincaptionofthc projecth 1988,ssaciuaryestsblishment
a part of the over-allstrategyof the CrocodileFarmingInstitute. Surveysof potential
sanctuarysiteshavebe€nundertakel. kke Manguao,a &eshwaterlake in Northem
Pslawaqhas.b€etrthorouglrlystudiedfor its potentialand a final proposalhasbeen
aodthe
of Taytayis appreherNive
of the munieipality
submitted.Thepoliticalleadership
of very poor
locsl residentsEr€opposedto the propos8l.The proposalfiiled because
socialacc€ptability.
that renewedeforts be rude to establishan
h 192, ihe CSGr€eommended
on a snall offshoreisland)and
ty f6 C nindorensis(perhaps
innovativ€crocodilesanctu
ore for G porosns. Tbis rnay leed to be done in cooperationwith the Integrated
wedandsfaunain
piotectedAre.8sSfstem(IPASj progpm andmay needto emphasize
*safe"
populariols
of these
genera!rather than crocodilealone. It would result h
&o"oa[o io tl" l" 4 andcouldin the longterD' form a basefor their ramhingby local
DeoDl€.This matt€rb most ug€nt becsus€of rapid humanpopulationgoq/th and
andotherwdlandfEuna
iestructionofwetlandhabitatsrc€dedfor crocodiles
The AsusatrMarshwiich is believedto be the best smongthe last remairdng
habitatshasfinallybeenincludedin the IFAS progam oo Octobcr31, 1996 However'
residingin
themsrshis beid dectcd by thegroryingconsunity ofManobotribalpeoalethe narslLilegslloCgi!& dounstreaneffeusof mining;ilegat fisling, wildlifepoaching
and tradin& &oCJtO seeding;8nd slashand bup farming Tbe ProtectedArcas
ManagemdtBoardof AgusanMrrshWldli& Safftuaryaodits Foject mana8flrcnthas
beenirgEaiziagthe communityandeducatingthemaboutconserrztionand susttirEble
a c€dainportionof the Agusan
utitizafJn. wiih oe idention of.eventualyd€signaring
zorc, tho CFI basconducledtwo
I\,Ia$hwildlif€ sarctuaryas a crocodilemanageruent
spotlightingsuveysin the Msrsh0994 aod 1998)' However,both survevs
systemaric
yiaa"A
ouda* to,rlt. Ini€r,"iewsw€re conduct€dwith the communityof Manobo
-ribesm"n
iho a.et""iding iruidethernarsh.Most oftheir vedal accoudsdid not 'eveal
back Themostreced itforrnation
io"t".d ii aatesbact to tew decades
,o*t
"ightingp,
is t&i itr Novenberof 1997thifty sh (36) eggsof unknowncrocodilespecies
howev€r]
for food
wse collectedfrom a nestby a Matrobotdbesman
beenunderthe confol
LiguasanN{a$hin Cotabatootl the otherh&!dh8safi'vays
SrouP'Much ofits original
ofthe M;o IslaqlicLib€rationF ont (MILF), a sec.ssionist
is still
to agriculturallaodssndmuchofthis khd ofdevclopment
ar€ahasbeencorryerted
it into an
expepted
to happ€t. there wasevena proposalto drainthe marthatrd.conved
atd C'
nindorensis
this'
C'
,giicuttu.f *i'"coootic zonefor rebelrenrnees.Despile
poroorsarestill beliwedto b€ srrvivhg in tbearca.
alreadydoubtedthe
Group(CSG)in its recommendation
TheCrocodileSpecialist
oossibiliwof finding even smallviable populationsas they cont€ndedthat the ooly
are singleindividualsscatteredalo€ the coast such is also the
lemainingcrocodilest07
indicationof the initial gurveyrcsults and the data gatheredby the CFI basedon
acquisitionrecords. But despitethiq CFI is determindto aggr$sivelypursuehabitat
establishm€nt.
surveysandtheev€ntualsanctuary
INIERVENTIONS
A. CsptiveBreedine
Duriag the Workshopon the Prospectsald Future Strdtegyof Crocodile
of the Two Spe{i,ff;(Crocdfl{s nindorercisard C. porons) Occuring
Cons€rvation
in 1992,the authorjustifiedthe captiv€breeditrgstrateg ofthe cFI
io thePhilippines
projecl to wit:
a. Crocodilepopulstionesp€cislyc' ninfurensis is npidly declidngdueto the
8nd expading use of traturebroughtaboutby the growing
indiscrinrinate
scattered
bunanpopulationov€rthearchipelago;
wheretllere
in all partsoftle Philippines
b. It b imprecticalto colservecrocodiles
andcrocodile$andwherethere
is aheadyaoo<istiagcoqflic{betweenhurnaos
befor€th€y
wereoollected8sbre€d€f,s
is peaceandorderproblem.Crocodiles
st therateit's goingandif no remedyis done
fac€loc€le'dinc'tiot|'B€caus€
thenexioctionis inevitable;
b€xtremelydificult 8ndo'?ensive;
thernin thewholearclripelago
c. Conserving
End€ducatedia orderto rercne the prwailing
d. P€opleqltrstfiIst be iDforqred
attitudeor 8t leastsrY8ytheir beliefbeforethey cao be tanghthort to live
with thesocodiles;atrd
harmonioudy
e. Hence,captivebreding is themostpracticalaltemativeandprobably'the ooly
optionleft.
thefollowing:
theCSGo.pertsheadedby Prof Messelreconmended
In response,
the removalof breedingadults&om dcpletedwild
Ulder normalcircunstances
the reproductive
becauseit depresses
populations
to stocks &Im is to be discouraged,
leavethe small
it
is
wrong
to
However,
rareoftle wild populationandslowits recovery.
nrcle{s ofbre€dingsdultsin areaswherethcy arebeingkilledby localpeopleandwhere
to dc€terBc€s.It wouldbe foolishrct to placethemin a
theirhabitatb beiogconverted
8ndwherethcy can€odibute
captivebreedingprograrnwh€reits survivalis guaranteed
progtam.t$afroljing C. nit dorensisin thewil4 beforcre3lprotection
to a consewation
would probablyhaveresultedir the
or sanc&nries,
cin be sccordedto themin reserves
th€yhadto
in thePhilippines.To savethe C. ,nitedorentiJ,
6nalextinctionofthe species
and
b€ takenfibm the wild and placedin conditionswhetethey caubrcedsuccessfully
(Messet
192)'
et d.
is possible
wheretheyoungcansnrviveItd flourishuntil restoc&ing
108
Messel et al. further recommad€dthst the acquisitiol of additional C'
for themm
is €stablished
mtdorensisbe @rfiE{teduotil $lohtime thai a safesanctuaxy
thewild.
were actively pursuedwhich resultedto the
ln response,recommendations
a total of
u.quiSJonoiiaAAoo"f C. mirdorensisstock.By 1994CFIwasableto acquire
twi-6undreaandrtrirtyfive (235)crocodiles(Tab. 1). CFI sincethe! stoppedacquidng
are alteady
Ut""d- stockstravebeeabreedingregularly8nd sub-adults
itJaif."-tlt""
=
u"""a. Howev€r,it murtbe trotedthat ooly4.6%(n 1l) ofthe total number
private
"i"rir*,
stocksdirecdy catDefiom tbe n'ild while the rest are fiom
stocks'
"ifoia",ioo
of the agedistributionof foundations
the ctassification
Al*
ini[""tl""tce
(n=175)arehxcblingsaadjuveniles'
Swectyfour percent
(Sumiler1998)
ofC. mindarensis
Tablel. YeadyacquiJtrLon
1987 1988 1989 l99O 1991 1992 193 1994 1995 1996 t997
$alchling
luvenile
Subadult(F)
Subadull{l,l)
(F)
Bre€der
Breeder
{14)
9
2
5
1
1
2
2
3
2
I
$M
18
7
6
I
2
5
3
37
31
7
2
34
71
5
1
29
30
15
8
3
3
Tolal
89
85
15
l5
17
13
-5
tl
235
l0
thqn
Usingall the availabtematurefoundationstocks,CFI wal ableto breed
(Table2)'
in captivepopulation
to th€ stqadyincrease
succesfrrllyiesulting
Oftheodginalfouodationstockoftwohuldredandtbirtyftc'eightyfourperc€nt
(n=198)
arestill alive.
oftbis
To date,forty four perc€nt(n=88)of the abovemedionedstocksare already
breeders.
t09
(Sumiller1998)
Table2. Populationincrease
of C. midorentis from 1988-1997
ffourfrEo
No. lilodalities
ol heads No.
96
1987
1988
t989
1990
191
t*2
t993
1994
t995
1996
1997
IE
I
l
2
l0
25
87
64
I
5
5.56 17
10.00 t6
26
132 50
3.52 t32
2N 192
4.00 18{
3.t7 207
130 203
1.46 2@
1,18 197
7
3
3
Tolal
'OTAL
CFIBFED
No. Morbli0es
ol heads N0,
%
H.ads
Lrve
38
7
197
2
I
137
197
t09
155
t60
58
248
71
1280
157
Heads
5.00
1200
705
382
5.63
746
7S
5.35
uve
llo, Modalllies
ol heads l{o.
%
t8
r34
305
S8
520
622
79
976
18
18
33
70
292
427
505
767
87
1078
1247
1
2
2
2
26
30
24
40
19
74
117t
342
H€ads
5.56 17
l t . rr
16
6,06 3l
246
58
690 255
5.69 497
522 727
6.99 E25
7.33 99
393 1173
. Thc BreedingPerfomancc
The6rst succBsfulbleedingwasrecordedin 1989whensevenhstchlingsemerged
fiom dnety two eggs. Ever sinc€thst time eggsand hstchlingswere alreadybeing
producedannually\r,ithvaryingratesofsrccess(seeTab.3). Fr's produc€din 1989are
nowclassifiedasbreeders.
It is expected
thrt F2generatiolwill beproducedvcry soonl
Tab.3. Anoualcaptive
results1988-1997
(Sumiller
breeding
1998)
Mean
llo.
Ftnale Laid BE€ding0ulch Harding of
Fetll3la
Pajrcd Eggs
1988
1989
r 990
1991
1992
r993
r991
I
7
t0
19
l5
I
5
4
12
13
12
24
20
16
22
26
20
ToiaVM€:n
121
MlaneJduding
1988
83
1995
1996
1997
21
Rate
Fertility ..---_!4!!!g_
Sze P€rBr€ederEggs N,o.
t00.@ 21
7t.43 18
10.00 24
63.16 29
85.67 38
0
I
4
ll
52.17 28
83.33 22
72-73 25
10
9031
t3
29
80.77 27
12
2f
92
94
352
191
331
446
397
571
573
1
25
?0
24i
359
246
320
320
451
415
%
4-76
25-20
30.99
63.82
75.00
58.46
69.56
74n4
75.16
70.58
3368 2409 5539
14.12 26
71.24 27
61.57
ll0
Yearly
No.
%
SlJrviwd
0
7
14
135
209
0.00
10.32
0.00
13.33
30.00
50.70
61.00
47.92
73.21
88.66
98
37.72
78.99
155
{8.42
160
253
46.74
g.5l
59.97
54.99
248
61.06
1280 4005
44.5
82.94
86.72
60.67
67.41
1173
The very high breedingrates and the inherentlylow hatchingrates (mean 5l7o)
comparedto the reiativelyhigh fertility (meatr697o)shouldbe mted' On-the overall, in
the tfI, the captivebreedingrf.rformall.p of C. mindorensisis very muchlower than ttrat
ofC. porosnswbich hasatr av€ragefenility rate of si:cy eight perccnt(687o)and a mean
hatchingrate of seventyfire p€rcent(75%).
The matter aboutth€ low hetchingrate is the biggestchallengethat CFI needsto
point to
solve. Thus,thereis r needto investigatethe stagesofedbryonic d€athasit may
being employed.It cluld be the quality
someincubationfrctors or incr.rbation.techoiques
itt"ff Msrais et al', (1994) pointedout t}at the quatityof th€ egSsis afiest€d
"itn" "gg
blfactors associatedwith pareqtalagg geletics' ard nuffition
rnainly
. Ere€diog Frcton rnd Behaviours
:r Brccder Cl8$sificttio!
C. mindorensisbrex/rersareclassifiedbasedolr the lengthalrdweight of
individuals.
Table4. Prodsctiveb'reedersize(Sibalet al'' 1992)
(cm)
Length
f4ate
215
flaleWeigtf
{kg)
48.4
198.25
(cnr)
female
Lenglfi
Note: The$nalle$rccord€dfemaleto lay egghada totsl l€ngthof 155cm ande
lorfy weightof i5.2 kg. Its malepattnethada total lengthof 156cm And 156
kg. bodywcight.
+ Brcedingrstio
Gen€rallybrcedersare pairedat a one is to one (l:l) maleto fetnaleratio
ofsome
dueto thcpeculiaraggressiveness
is trotvetysuccessful
b-reeding
Comnnrnal
At
bre€ders
arebasicallysolitaryor monog-amous
bre€dingmal€s,Thesecrocodiles
in conmun8lpensto
aremaiotaioed
sub-adrltsand.iuveoiles
present'young
bre€dets,
getus€to thissocialenYironm€ot.
llr
3 Ptiring and compatibility
Very critical to the suc4€ssofbre€ding C. mindorensisin aaptiity is rhe careful
selectionof breedsrsto be paired.A pairing plan is preparedway aheadthe onsetof
the breedingperiod. Pairingis basedon origin andphysicalcharacterssuchas length
ard weight. As a rule, the msle shouldbe bigger and besvierthan the f€male. Ages
are unknown since they sre stocks from the l,ild. Pairing is uslally done on
Nov€mberto Decemberexceptfor aggtessivebreederswhich arc paired very late in
February.hcompatibie psirs resort to fighting especisllyduring the erfire breeding
season. Fighting usually occur during courtship,nestingand post nesting. Injuries
susiainedare usuallyvery seriousand may resultto death.
= Brecdingperiod
Under normal weather colditions breedingsessonin Palawanis betweenthe
month of Februaryand October(Figure3).
+ BreederAcclim8tizstion
Breedersacquiredby the CFI did not readilybreedupon pairing. This is true to
both wild and caprivecrocodiles. It took approximatelyl-2 yeatsbeforethey bre€d.
= Brceding rate (paircdfemalesrs. nesters)
It rangesfrom 40-100o/o
breedingrate or a meanbreedingrale of 70%.
:? Clutch lize rrtrge
l8-33 eggsperclutchor a meanclutchsizeof26.
:+ Fecding!!d supplementation
Breedersare fed twice e week (Monday and Thurday) 8t 3% bo& weight.
Feed qrpe laries from fisl1 chicke4 beef, po* 8nd carabeel F€€d allocation is
supplemented
with vitaminsandoyster shell.
= NestiDg
In addition to existing vegetstion inside the pens, nesting materials zuch as
bamboograss,leavesand ric€ straw sre introducedin ranuary(Sibal, 1992).
t12
I
-'rn
+
cradmt
R.,nl'll
TmFatud
^
\
F M A M,
t A 5 o
MOIITN
N D
Fis. 3. Etg Lryint Season
113
. Incubrtion
Properegg inqrbationis very vitsl in captiveoperstions. The harchingand
mindqensbeggs8ftiffl,€llyircubatedat theCFI ar€showing
survivalratesof Crocodyrrrs
poorresultscompared
by C.porosr,s.
to wbathasbeenachieved
on the
A retrqspective
studyon ihe efiect of diferent incubatio[temperatures
fertilized
eggs
were
A totsl of 1,470viableor
hatchi[gandsurvivalraleswasundertakeo.
seuingsfiom 30oCto 33"C. Resultsshowri'l Tabl€5
ircubatedin ditrerenttemperatr.lre
revealthatthe highesthatchingratewasattainedat 30oCwhile8t 32oC,tlle stwival rate
high &om the third to the twelfth monti of observalion
of hatcblingswas consist€ntly
(Sumiler1998).
Table 5. Hatahingaod survivalratesof C, mitdarensiseggsincubatedin ditrerent
(Surtiler, 1998)
incubatioatemperatues
ln ubation lduallno.r.
('C) Temperalurc
('C)
S€flinq
30
33
29.97t 021
30.95t 0.3i
32.10
10.31
32.91
):023
&de Eggs Eggs H"rd'i'E
lgg!:gjSElltr:-u5g
lncubatedHatched Rale 3mos. 6 mos, 12m06.
366
406
311
224
189
214
129
78A1
62A2
53.57
47.97
81.37 7934
78.n
78.28
91.90 91.32
73.90 73.90
7239
71.68
85.98
72.01
Otier factorswhichcanirfluencehatchingandsurvivalratesare:
1. Qualityof eggswhichis basicallyinfluencedby parentalage,genetics,andnutdtion
(Maftis et al. 1994);
2. Incubationfacto$ (humidity, temperatureatrd gas exclnnge), techniquesand
ma0agerne;
especiallyafter six months- Huttou (1984 Pointed
3. Resringtechnique/nanagem€nt
out that the growth and $rvival of hatchlingsfor the first six morths of life is
influeac,ed
by theincubatiortemp€rahfeat whichtheywereincubated;
- hheret$to the lp€cies;and
a. Species
idiosyncrasy
genetic
5. Puely
relsted- in the caseofa groupofbreedersfrom Bacolodlthich hada
coosistentbhighfertilityrate anda verylow hatchingrate.
lo relation to the incubatiol perforrnanceof C. mindorensis,@ns€rvative
vitaminsand
measurcsare now beingundertakento improveit like supplemeoting
mineralsto all the feedallocationof crocodiles,stdctfeedqualitycontrol,properwater
improvingoo incubationmalsgemcttt,he*ing the rearingtanksespecially
tnansg€ment,
duringcoldrnonths,andgivingspecialattettionto poorperfomhg brceders.
ll4
To further investigatethe problerL an embryonicstagitlg studywill be undertaken
this year to determinethe diflered embryonicagesof modalities so that o<temalfactors
which could havedirectlyinfluencedembryonicdeathscould be pin pointedandconected.
*lfater
*srulidity
banagenent
*r,rutrlrlon
*Pal.ring/conpatili.Ii!y
*Age of, breeders
GENETICS
i8reeding
419.
.
4. rrlad
of
factors
affectlng
& selection
the
success
of
breedlng
and incultation
TemperatursDependentSerDet€rmilstion
Elsven out of22 known speciesofcrocodilians showedevidenceof temperatuG'
dependentsex delermin4tion(TSD) (I-ang 8nd Andrews 1994). Coher atd Cans(1970)
that TSD maybe universalin crocodilians,in contrastto turtles andlizards.
spec'ulated
This fact pronpted CFI lesearchersto s.rbjectthe C. mindorensisto TSD analysis
- in relation to the above mentionedincubation temperatursstudy. Preliminary d8ta
garheredfrom 586 crocodileswhich were subjectedto different inqrbation temperature
s€ttingsshowedevidenceof TSD. The lower the temperaturethe higher lhe numberof
f€rnsles,snd the higherthe ternperah.rcthe higherthe rumber of nales. However, there
is a probability that the much higher temperature(3a'C) codd also produce females
patt€m (s€e Table6) similsr to relatedstudiesin
resultingto FMF (femate-male-female)
C-Woslts, C.johrrstoni, C, niloticus, ad Cumar.crocodiles.Due to tlle risk of wasting
Grtile eggsil high tenp€rature(34'C), incubEtionof eggs8t this s€ttingw8s discoursg€d.
Liw C. m dorensis hrtcl ings are more valuablethan knowing the rcol effect of high
temDeratules.
lt5
on the s€xdistdbutiooof C
Table6. Effectof dif€retlt hcubationtemp€rature
(Sumiller
198)
rzindorezsis
lnc!balion
Sening
LtualTemp
Reading
("i)
{9
30
31
32
33
2996t
30.99I
31.99i
32.91t
34.08I
0.33
037
0.32
0.32
0.05
ol
Number
Cro(sSF:Ed No.
39
40
220
202
167
255
710
69
22100
%
1
t6
92
65
88
62
0
3
8
35
90
0
. Re{ring
f{Nry eq C. ninfuruqis hatclrlingswere reared in water temp€ratuteregulat€d
rearingtanks. The hatcblilgs were randornlydistdbutedto thr€€ (3) ffeatmentswilh tt[e€
(3) replicat€shavhg teo (10) headsofhatchlirgs €8ch.
Treatmentl: wat€r tempentlre regulatd at 32'C with
continuousflow ofhot urdtersupply
Treatrent 2: water temperaturcr€gulated&t 32C with
htarmittent flow ofbot water supply
Tr€tm€nt 3: Gortrol
Initiat datagBtheredsho$'edthat animalsrearedia Treatmelts I and 2 grew faster
thar the control (seeTable7). .
Table 7. Initial and final measurerrensof crocodile hatcNi4s reared in water
temperaturer€gulatedlanks(Lagada 1998)
tuy vi"gttl(S)
TddLenglh
{sn)
SndIv€rnFnglh(cn)
Head
tl TtAL
T2 T3
l1
&6451
26 27 26
12 12 12
414
3 t'lofllHs
117 241 94
42 45 33
20 22 16
664
. Stmkin8
from 230
A totalofninetyoneC. ntitdolsfrdsbatcilings(8 monthsofage)tanging
to 880 gramsin bodyweightor 44 to 68 cm. In lengths- were subjettedto diff€re
l16
sizectass(meanBW : 300)
stockingderuities.Thegroupwasdividedinto srnall-medium
sizeclass(meaoBW = 530)beforethey w€redistributedto rearing
andmediumJarge
tarksofdifferentstockingdersities(seeTable8).
Table 8. Mean body weiShts of crocotliles reffed in diferent slookitrg
1998)
densities(Sumiller,
Td*
flcF
6
8
10
12
15
1
10
6
mZ
5
5
8
t0
12
Bvv
G
3@
300
300
300
300
9 Eusbstrdrysupporl
Theanimalswerefedwith ninc€decat fortii€d with vitaminandrninerals They
ta[kswhichwerealwaysclesredthedayaft€Ife€ding The
werekeptin fiberglass
lids of tire penswerecoveredwitb sacksandheatbulbswer€plscedFovidedto
increas€
thetempentur€ofthe tatkInitialresultsshowthefollowing:
r Growth rateswere high at lowar ad higherstockingdcnsities(10 ad 5
aniuulspersq.m.)for themediumlargegroup(Table9).
r For tlose teateAin to' stockingdeusity (3 crocodilesper sq'm'), the
€nvironment
Fovidedltre spacefor onehatchlingto displayterrhodalinstinct
re$ tingto thekilling ofal its penmates.
anddominantbehaviour
r Growthrrtes riere high at hi8fierstockingdensities00 8nd 12 animalsper
sq.m.,l.
Table9. Averagegrowthtatesof alocodilesrearcdat difereotstookingdensities
(Sumiller1998)
Sll^tl--l'lEDlUl'l
lrirEis fuimal' Ave. P€rcenl Ave. Percer,t MmaL lninils Ave. Percenl Ave Percenl
ll(cm) lnseded p€thnk perm2 BW(gllEE€ql!.llll-lncrcased
oertank Dern2 Bt!{q) Increls€d
14
56
541039
6
67.3 1
O
4
3740
17
55
640034
8
67
15
658r054
10840035v11
8677047
16
68
58
12
10 490
62
6
620 12
ro
b
18
59
15
12 550 83
t8
860
62
12
r0
itEDtut'l-uB6E
tr7
. Nutrition
of
to investigstethe feedand autritionalrcquirements
Studieswereundertalren
m darensis.Anong thestudieswer€l
Crocodyfus
l.
utilizingmixedfeedrarions
ofc. mindolensishatcblmgs
Thegrowthperformance
to four dietrry treatmentssuchas combiaedpork and
Hatcl itlgs were assigned
chickenheads,carabeefand chickenmeat,pork and obickenmeat,and pork and
pork and
itrdicated
thatconbitredchiclcermea andcarabeeflikewise
canbeef Re'sults
carabeefsiglifcantly yieldedbeaer te$lts considedngthe total length of the C'
in weight gain of C
nldorensi hstchlings. However,no significantditrerences
ninturensi$lrltctfifigsfed with difrer€fffeedcombinatio!werefound- Therefore,C'
utilize feedseffciently givendiferent feed combioations
mtufurensishatcNings-can
(Zsbala198).
of C. n furensis h$crni'J'gs
2. Proteinrequilemeot
averagit871.5-180.9gramsbody weightwere used
C. nindorensishatcl"rings
ad fed di€t cootaining50.97%arudeprctei! Feedingperiodand fecal coll€ction
of95.94%Fotein digestibilityofc'
lastedfor sweudays.Resultsrwealedanaverage
nindore$is latohlings. The digpstibleprotein requirementfor C' m dorensis
hatcNir8swas 48.98lo. ThereforgfornDlatingfeed for C midtrensis b"l*lings
shonu ;ntain at l€astthe requiredvalueto ssdsfythe proteinrequirementof C'
(7'ab.la1998).
nirdoruEk h8/,clfittgs
of aminoacid ta C- minturet6is m€atusrogpaper
of the pr€.senc€
3. Determination
chromatography
hasonly eiglrtkindsof arnino
R€$Jtsshowedthat C. ntfulensi| t\d s,sllrlple
isoleucine,methionine,
leucine,
acids. Theseare thd: phelrylslaningnorleucine,
norvaline,valirc, andalanine.Etbaoolandwaterason€solveatrtas usedandbuta[ol,
with
ac€iicacid and nater as the other solverf. Furtherstudy is recomrnended
(Zabala1998).
to be adapted
on procedures
emphasis
l*chlings
of C. mindorensis
4. Delennioatiorofdlc minifiumvitamh requirement
Sixty (60) C. mindorensishatcblingswere usedand fed with po* for ten
month6.Resultstwealedthst tlose hatct iogs8iv€n8 diet with vitanin supplement
of0.5% feedweigtrthadhigh€rbodylteight gaincoopar€dto thosefeddietswithout
vitamins-ard with vitanins at the rat€ of 1% atrd2P/ofd werghtthroughoutthe
highe'total
f€ddietsofo.s% fe€dweighthadconsistendy
feedingpedod.HatchlitrSs
length comparedto othe! trestmetrts.The difierenccsb€fi'veentteatmentswith
regardsto bodyweightandlengthweresignificant.
ll8
Basedon the body weight guy C. nindorensishatcblhgsshouldbe given
vitaminseariyin life. The minimumamourfof vitami! that canbe giv@ is 0 5%
1,575I.U. Vit A 450I.U. '/it. D3;0.525IU Vit E aod\rlt B(whichcontains
complexwith higheramountof Vit. B) of feedweightwhengiventhe \'L strength
asthebrandofvitaoins (Zabala1998).
was done'
of pepsinad trypsitrin the C mindor€nsis
of the presence
6. Confirmatiotr
pepsin
and
andfoundto have
of stomachcontentsandftces wereexamined
Samoles
trypsiqin thebodyof C. nindorensis(Zabla 1998)'
on Ming behaviouras displayedby C' mindorensishetchlingsand
? . Observstions
juveniles
8sd72 iNenileC' nindorensk crocodiles
Obs€rvatiolwaslimitedto 128hatcblings
a week'
weregivenfeedallocationof 37oof theirbodyweightsald fed three-.times
il feeding running rnd hiding.when the
srch as aggressiveness
M;6;i";
caJater is approrcbingaodo'til"rl'aitiog fot food to be plar€din f€edingtroughs
rstum
l"eru oUt tu"i. Mostly-theaninalswill ru5hto gst to th€ feed8rd inunediately
tend
to
that
feeders
to the waterwheretheywill fnatty eatthe food Someue shy
no* ,tor"tytootatdsthe foodlocationwhereothersaretakingin their feed Juveniles
onesare the biggeranirnals The
Mostly the sggressive
hustletowardthe M.
oreaLi.ones just wait until tlere is alyrhiagleft somelate.movinganimalswere
"riil ihe foodprotrudingftomthemoulhoftios€ whohavealr-eady
taken
to grab
observed
ac.coutof tbefe<leg bdraviourof C' minfure"siscarl
theirfood.A-$'elldoorment€d
md mamgem€ntof the animalis
O" of gt impodaoceas Ar E3the cooa€rvstion
ofdata in
theanalysis
wouldcomplemeot
*n""ti"a."t f:no*fuagr on feedingbebaviour
studyitrgihe variou aspectsof.theaninal(Abab 1998)'
RstebYClsss
8. FeedConversiotr
The fe€d coowrsionrste of C. mindore,rsishathclings,juveniles,sub-sdults'rd
breederswerestudiedinig92.Itwasobserv€dthathatchlingshadthehighestaveiage
to the oldl crocojill As.rheanimal
iCn, foaiog ratq andintskerste as compared
thusthe lowerFCR Physiologicsltlhe-biggertheanimals'
ages,its fiintak" Oecreases
iie sto""erttrebasicrnetabolictate (BMR) th&ti5 why theyfeedlessi! terr's of amount
and&equency.
. Discss€s
rtrd Clioicrl Csscs
A totatof 96 clidoatcasesinvolvingthe C' minfurensiswereLoledfom 1987to
1
1997. Of the tota! 40 easesweretraumaticin nature'5 metabolic(runt synirome)'
mortality
nutritional(calciumddciency),l0 congenita!andi6 derrnaiologic'Theoverall
119
raie in clinical caseshad been placf,dat l4.sayo (14 out of 96). Most monalities in
patientsinvolvedthosewith congenitallesions(n=7) aodmalnutrition(n=3).
Tiauma aasesu$ally involved lacerationsdue to fighting with ody one case
€xhibitingskull ftacture. Lacerationswere suturedclosewhen possible. In somecasesof
d€nna.llsce.atio!y'abrssiorwhich presentproblemsin their closurg the wounds were left
to grarulate. Skitl closurewas previouslydone with unabsorbablesuture. Since 1995,
however,cyaooacrylateadhesivehadbeenutilized witi relativesuccess.
The runt hatcl ings were prwiously treated individusly with parenteral
admidistrEtionofmultivitamins. As of 1997,howwer, ideatifiedrunts $'ere now routinely
rgregated andplsc€din tsnks providedhtemittently with wrfm water. This therapeutic
regimenappearedto have producedgood resrlts as of writing. Other cliaical problems
observedin hatchlingswere that of the golf bal yolk syndrome. Still others included
congenitalanomrlies,e.g-,incompleteclosureofbody cavities!cleft pal8te.
It was inte.estingto rcte that dsrrnatologiccsseshav€ not been encountgredin
rec€ntpast evenwithout any distinct charge in managemerf. It was quite possibletlEt
these dermatologiccaseshad been due to poor conditions observedin their previous
locrtions srd which hsvebeenimprovedilr their presentlocatioo.
Majwity of C. nitdorensts mortalitiesbelongedto the bstchlirg ct8ssasillushated
in Figure 5. Deatfu in this classwere often causedby thermzl stressand steatitisarnong
othe$. In relstior to this, the runt syn&ome h hatcliings had been speculatedto be a
form of chronicthefmatstress. Juvenilemortalitiesbad alsobe€ntefltstively diagnosedas
steEtitisand thermal stress. On lhe other hsn4 bre€deraod sub adult monalities wsre
mostofter dueto trauna incurr€ddudng figbts.
120
Etezrdorll'ol C nlndorcnsisfionalilieslrom | 987lo i998'
{roral:351)
(Aquino,
Fig. 5, Graphshowingthe mortalitiesofC. mindorensis
from 1987-1998
1998)
It was notewonhy that neclopsyofrunt monalities h lhe rece pastrevealedno
intestinalpalasites. An also notableinding wasthat other anatomicalanornaliesoften ran
concurrentwith cleft paiatecas€s. In fact, necropsyof two cleft pElatemortalitieshave
revealedunpairedkidneys.
TreatmentStudies
a. Use of cyanoacrylateadhesivefor skin closureiz Crocqrl$
porofls
mindorensisard, C-
The use of cyanoacrylaleadhesiveMghty Bond6t) in skin closure in tlree (3)
Crocodylxs mindoretsis and two (2) C. pqosus of varying age was relatively
successful. Keloid formatioq handling time and stress due to handling was
reduced. No adverseeffectswere noted. Howwer, sinceefficacy could only be
ev&luatedthrough ocular inspectiorg the degree of successcould or y be
approximated(&uino 1998).
b. Surgicalremoval as treatmentfor unabsorbedyolks in hatchlingsproducedat the
CFI
Thineen (13) hatchlings(7 C. mindormsisl6 C. polosrr) presentedto the
Crocodile Clinics Unit fiom July 1995 to De{ember 1996 were tentatiyely
diagnosedwith golf ball yolk syndrome.Their yolks were nugically removedand
examinationof the yolk sac contentsrcve{.ledblood clots, congea.ledor petrified
yolk either in combinationor alolte. Out of thesecases,eight (8) patients(3 C
l2l
mindorensis;5 C. porosus) stccessfullyrecoveredfiom the surgical procedure.
The synd.omewas thts sp€culatedto be causedby physicalobstruction- Other
possiblefactorssuchasinfectiol andtrauna were alsocomidard (&uino 1998).
SPECIES IDIOSYNCRASY
During the courceof captivebreedingof Philippinecrocodiles,peculiarbehaviour
andreproductivecharacteristicswere observed. Someofthese are:
l.
IncompEtibility
Although this also happensin sa.ltwatercrocodileg Crocdylxs mindorensisha,te
exceptionallyhigh incidenceof fghting resu.ltingio t aunatic physical injuries and
deaths(Table l0). There is a marked increaseduring the pairing and strn ofthe
breedingsqson whenbre€dsrsare stsning to adjustto eachother.
Table 10. Number of casesof aggressionalnoog br€€derswhich rcsult to
woundinganddeath(Sumiler 1998)
No.d Paired
No,ol ke3
&E€deB TrauriEtc
lhunds
Deaih
1993
r991
1995
1996
1997
24
22
8
t0
0
0
2
3
2
14
22
26
Perceitage
{$)
34.78
41.67
63.54
53.54
51.54
Theoccurrence
of suchbehaviorhadno specificperiodoftime. It rnayhsppen
dudng counshiA dudng nesting,and post nesting. Femalesare usuallythe victims
althoughtherewereisolatedca6esof malevictims.
practicesbeitg doneto dealwith theproblernarethefollowing:
Husbandry
a. Females
arefirst intrcduc€dto thepen&tGw weeksMore the intoductior of
thernaleto allowto estsblishherownterdtory,
b. Tc€tharesometimes
cut by filing.
pairsare irDmediErely
c. FightiryAncompstible
separated
beforeseriousinjuries
,
occ-tlr.
d. Victims aretreatedand allowedto recupef,ate
beforethey are 8g8inpaired.
e. I-ate pairing
f; SeparationofbreedersEfterthe breeditc season
t22
2.
Multiple nestingor <doubleclutch"
Peculiarto this sp€ciesa.lsois the cas€ofmultiple nestingbehaviourobs€rvedin
some pairs. Clutch sizesdo not vary very much. However, fenility and hatching
ratesvdied whereinit raasobservedthat the 6rst clutchesof eggshave higherrstes
of hatchingover the secondclutches.
Tsble I L Ca6€sofmultiple nesting(Sumiler 1998)
oulcn9:c
No.
t99t
t9
1992
Day!
%
5.25
657
134
29
24
4,17
r35
24
135
2A
l3r
10
23
79
151
F.rtiilvtulc
ld
2nd
lhlchino&L
Id
znd
7&57 *.@
9655 &rm
875 €0.87 8.a1 7AS7
1991
t994
1995
24
22
1
135
1@
79.17
9565
42.11
9583
8929
91.30
72.6
The secondclutch is oonn8llylaid five to six monthsafter the ftst clutch.
3. Eole nestitrgstrd decoymoundncstiDs
Another form of idiosyncrasyof tNs speciesis hole nestingand decoy mound
nestingbehaviourdisplayedby at least four (4) aclive fenale breeders. Three females
were observed6rst formingtheb mould nestsbeforelayingtheir eggsin I hole dug-out of
the loose soil in their pens. This diversionarytactic fu b€lievedto be their naturaldsfense
mechanism
to protectlieir eggsTable 12. C. mindoleruis femaleswhich displayedhole nestingbehsvior(Sumiller
1998)
F.maLS tlo.
132
134
395
Tobl
Mean
r995
1995
1995
1998
tio.ol qgs
F..l$tyilo.
Halchab[t
18
t2
l3
zl
22
1l
9
2l
25
8125
100
88
I
21
t23
9tvtudtu!.
9ls7
6923
4,76
t1
9
0
100.0
1000
00
4. Corgedtal anomsly
A p€culiarcongenitalaromalyw-asparticuladyobservedin tle progeniesof
breeders
from BacolodCity andNegrosOccidentat.Ilstchlingswereroticed dyingfew
daysafter hatchhg. Necropsyresultsrevealiacompleteclosureof thc hard palates
technicallyknownas "cleft palate". F€rtile 8s ftom the sarneclutchwhichfailedto
arebeing
hatchalsorevealthes8mefarslabnorm8lity.Thes€palticulargroupof breeders
study.
to vitsnin srpplenentation
subj€cted
INFORMATION, EDUCATIONAND COMMTJNICATIONSTRATf,GTES
and
ManyFilipinosvierr crocodilesnegatively.In promotingtheir cons€rvation
good
on
b
that
CFI
capitalizes
thing
that negativityrules.But the
use,it seems
sustainable
positive.
liesin nrmingtherninto something
all thesercgatives.Theohallenge
in €ducating
Alongthes€lhes, CFts IEC programhavemadeimportadheadways
of crocodilesandtheir €cologioslatrdeconomrc
the publicaboutthe realcharacteristics
itnportarceas well as disseninatingappropriateinformatio[ about the ac'tiviti$ and
objectives
of theproject.
Since1988,the Institutehasproducedand distributedat le3st225,000prioted
cardgprofileq andperiodic
infontratiollmatedalssuchasbrochu{es,postgs, calendars,
fepons. The qua*erly ofrcial publicatiotrCFI Nes|s-wasdistributedto researehand
gov€rnmentinstitutiotrsin the Pbilippinesand abroad.Starting1998,CFI News and
Research
Buleth (s biatuualpublication)will be circulatedeveryJuly 8trdJsruaryin
placeofCFI News.
in En8lidl and Filipino for adults and childrsrL slide
Video docurnentaries
presentations
i! Eqlbh ad Fdipinonot to mentionladioplugswerealsoproduced.Two
System.They8re
plws wereproduc€diu cdordinationu/ith the PhilippheBroadcasting
still beingairedfieeofchargein 25 radiostationssll overthe courtry.
arealsowitten aegulady
PressreleEs$aboutCFfs activitiesandaccomplishments
print
for themedia.CFI enjoyeden€nsivecov€tagein thelocal,nstionalaodinternational
and kosdcastmedir thesepastyears.PopularTV showsand influ€fiial TV networks
havealsofeaturedtheFoject in th€ifprogrsrlls.
are
In PalawaathePhilippineglocodilesconsdvationFoject site, IEC carnpaigns
in
have
been
conduoted
iaformalioa
campaigns
being e*ensively done. Numerous
crocodile-inhabited
areesand schoolsall over Palawanther€by educatingteDs of
andthe CFI projecl.Alnost all of
&ousandsofPalawefiosaboutsocodile cons€rvatiotr
by landbavebeencovered.Oolya
accessible
the south€rnard thenorthemnurnicipalities
reoainsureached.
handfirlof islandrnuoicipalities
l2-t
Andifthe padialresultofthe surveyon theimpactofthe infotm&tioncampaignis
hasbeenpositiveBasedon tabulstedl'348 questiot[8iresof
a.!yindicdio& the indPact
agreedthat crocodiles
95.7vloofthe tespotrdents
all overPalawan,
aoaternotret"
efforts'
"triae*s
answeredtiat thcy supportCFI'Sconse!'vation
shouldbe
"onserved,83.53%
poceive
crocodiles'
they
82.49l" repli€dthattherehasbeeoa positivechangein theway
and91.25%saidthtt tiey likedtheinformationcanpaign'
were crnductedin other psrts of tie aourtry as well They
IFC campeigns
orl crocodilianmyths'factsaodfi8ures'
leo-tur€$
consistedof viioJsfide presentations'
6lmslor
-J op* i"t" placeswiti commudtytel€visionweregivenCFI documentary
areas
Mindanao
the
ouUti"'ui"*ing.filipioos in otherpansoflerzon andthe Visayasand
throushdreri-media- radio,televisionandprint'
i"i ittf"-.ai"a
"i"*r.a
wary hnrn1rrbeinp canbe convertcdinto b€lieversof
Basedon CFI experience'
reasomwhy
it **"t""tion grveodentifically-backe4economioally-sound
-o p"ffi
mutuallybeneft&omcosdsteoce'
andhownan andcrocodiles
Also part ofthe IEC Fogramis panicipationin tradl--,9 P-iy fain aswell as
of the
other exhibiis.CIII hasb€; partiqpatingin the Emusl Philippile Travelnart
was
booth
A
CFI
1991
of Tourisdr8spErfof the Palawandelegationsioce
O-.rtt-t
City
duringthe pastarnua!Agro-IqdustriatTradeFair of the
rft"
atl r*
"i of""""toas
Puerto Princesema*ing its aity fiesta arld foundatiol anniversa4y
celebrations.
Weekin
Moreov€r,sinc€1995March611 is declaredCrocodileConservation
Resolution
possible
by
puertopri"cesa'City.
This amualsevendayc€lebrationis made
-;;;
"tle
of puetto ptin"to in supPortof crocodile
ty
city GoYerDment
ffi;!
slpws' open
co .rr,ationeffoi't".Essaynrritingaadpabtiflgcont€sts'conservation-quiz
aresomeof
and restrainilgtechniques
lo"te ;J a.^t""trud*; of crocoOite'haadtiag
festivaltheactivitiesdudngtheweek-l-ong
The misinformedand the udnformedusuallythbk crocodilesare ferociousand
visageSo how do you makea
dangerousbecluseoftheir relativelyugly ard fearsome
'appenling?"
Use a mascolA irocorlilensscot cantakethe edge(or at least
croJo<ne
it is
negativenotiols aboutcrocodilesb€cause
**" p"rt oiitl oeirc urualpreconcoived
imens|e
i*A"fb, nuggubb-A fimny.Theuseof mascotcoupl€dwith extensiveand
showg.lhat corfrary
provingeffecliveto the project CFl experiences
IEC carnpaigns=is
to the commonnotionthat oascots CiitOtn g adultsalsovery weu id€ntifiedwith
"."excitement
aodenjoym€otof their childrenbut by
not only throughthe
CrokeeprobaOly
albeit
f*tiog i c-[.. tf*ulf, the eyesof the childin them.It app€arsa cuddlesome
quitebig (202omt8[) felloeris hardto rcsist.
w-asintroducedto
Crokeeis beinggivenmaximumpublicexpoglle The-mascot
'crokee Goesto
the schoolchildrenofpuutto ptln"e* duringthe proruotionalactivity
Schooh".Cff hasalgoidentifiedftstivEls,holidaycel6rations,lowu fiestas'8nd other
Crokeeis beinggivenmaximumpublicexposure.The mascotwas introducedto
the schoolchildrenof PuertoPrincesaduriogthe promotionalactivity.Croke€Goesto
Sahools".CFI hasalso identifiedfestivals,holidayc€lebratioos,
town fiestas.and other
com€rvstion-related
activitieswhere Crokeecan play a part. Thce appearanccs
are
expected
to endqr Croke€,themascot,andultimatelytherealcrocodiles
to ihe public.
Freelecture-guided
toursaroundthe Institutefor tourists,studerts,academiciam,
teahnocrats,
govenrmentemployees
andtop brass,mediapersons,polilicos,diplomats,
oth6 VIPSandc€lebritiesarealsoconduet€d
yesrround.CFI is opento the publictom
MondEyto Saturdry.
Beforea tour cotunences,
visitorsare briefedaboutcrocodileconservation
and
sustainable
utilizationandtheCFI projectto rnaketheirexperieac€
substantive.
Exhibition
andlecturercomswereput-upandvideodocumentaries
areshownto visitorsbeforerhe
aclualtour.
Promotionalmaterialslike streamers
andbillboardsarealsoprominenttydisplayed
on slrategiclocstiom.CFI believesit is not enoughfor domesticard for€igntourist to
"just see' arocodil€s.
ln manybattlesto combato.tinctioq 8n inforrnedpublicis indeed
thestrongest
weapon.
T8king advantsgeof teachablemomentsaod opportunitiesis preachedand
practicedby CFI. Oneexcellentexampleis CFIS ,,toilethumor',hformationcampaign.
Crocodilianfarts relstedto excretoryand rqrroductiveorgsn furctionsare pres-nted,
tastefirllyard humurously.
The increasing
numberof guestswho visit CFI amuallyhavemadeit a musr-s€€.
For tfie pastfive yearstow, CFI is probablytheNo. I touristdestinslionin palawal the
Philippines'
LastEcologicelFrontier,averaging
morethan40,000visitorsannually.
ANNUALNT'MBEROF CFI VISITORS
Yeat
Number
I98?
6y
1988
1989
r990
l99l
6,993
24,X4
13219
21,139
25,&4
31,567
19n
1993
t994
1995
l9
1997
TOTAL
42,611
63,596
mstt
But moreimportantthanthe numbersis the fsct that all CFI visitorsare educated
aboutcrocodiles
andtheCFI proje€t.Theresultofall theseactivitiesis a significantris€in
thelwel ofpublic awareness
andappreciation
ofthesemuchmalignedandmisunderstood
species.
126
POPUI.ATIONPROJECTION
on the numberof
The futureof thfuconservation
endesvoris geatly dependent
produc€d
in captMty. It would
crocodilesasa foundatiolstochthat aanbe s€cur€dand
thusbebelpfulto visualizethefutureandexploreit by forecast.
A forecastis herebyattemptedto projectthe Crocdylus mirdorensispopulation
to s€€if there is a good future. This forec.st will be basednuioly on thr€€ major
assumptions:the aurrenttrendsof captivebreedinghypotheticalstandards,and the
projeetedschedule
of maturityofpot€ntislfemalebreeders.
ln additionto the existingpopulatiorof femalebreeders,new pot€ntialfemale
breederswere identifiedand their year of se,\ud maturity and reproductivitywere
projected. Thesefemalebreedersard potentialbreederswere utilizedas the basisof
for projectingcrocodileproductionasthsy produceeggslrhich in turn will
comput8tion
production
indicator(s€eTablel3).
bewed as
Table13. Projectedfernalebrcederpopulation(odsting+ pot€ntialbreeders)
Year
l,lo.of Females
1996
1997
1998
1999
2000
4t
49
105
l4t
157
zo01
2002
2003
2004
2005
221
237
Two breedingstandards
wereus€d:the pres€ftstatrdard
or 'CFI Trend"andthe
hypothe{ic8l
standsrdor'Target Strndard". Obviouslythe'tFI Trend"will be based
entirely on recordsof CFI experienca,vNle the hypotheticalstardErdot "Target
Standard"is theide3lwhichCFI is airing to attain(Tsblel4).
121
Table14. Breldingstandards
Pranes
l4e CFTrcd
TargdSbdad
71.24
27.@
m
Breedng
Rae
outi Size
Fstility
Rde
lHcHi[tyRde
tur/i\rdRde
30
80
44.n
67.41
80
qt
Breedingfactor (B) for both standardswere derivedusingthe following formula:
81=B,xC,xF,xtl.xS,
This simplymeansthe hatchlingindex per femalebreeder. Thereforq CFI Trend
would be 3.56 and 12.00 for Target Standard. Using this breedingfactor (Br) ss a
multiplier, populatiol was projected annualy bas€d o[ the projocted female breeder
population(Tablel2).
Ex. Anrual crocodileproduction= Br x numbq ofbreeders
Therefore,for the period of eleveny€rs (1995-2005)if aI availablebreederswill
be utilized productively, it is projected thar CFI will be able to attain a total C.
mindorensispopulationofltzQ usiogthe Tr€nd ard t8-768 usirg the Targ€r.
r28
Table 15. Crocdyltrs mindorensispop$lationprojeationfrom 1995to 2005
Breeding
Fador
llo. ol &e€d€B
1995
1996
1997
1998
1999
2000
2001
2002
2003
2@4
2005
4l
69
r05
141
ls7
173
189
205
221
237
Trcnd
Targel
12.096
r2.096
12.096
12.096
12.096
12.096
12,096
3.56
3.56
3.56
3,55
3.56
3.56
tzm6
12.096
r2.095
12.095
Toral
Prcieded
Productio.r
Trcnd
Tae€l
93
t{5
246
374
502
559
516
673
730
312
492
828
1260
1692
1884
2076
841
2844
5-370
18-768
2460
Populationpaojection
basedon Trendwhichis actuallybas€don the poorbre€ding
performance
of C. nindnrensisis very conservative.Becauseof thig thereis a strorg
praclicesascanbe Foven
tendency
to surpass
theTrendbeaause
ofimprovinghusbandry
(Table16).
by theproductionrenrltsof 1995-1997
Table 16. Crocodylusmindorensis corrpu*ive production perfonnance(Actusl
rs. TrendandTarget)
Y€(
ilq d &€dEs
Trcrd
TaWt
ls6
1S
1g7
41
93
146
2t6
3t2
492
W
Ltd
160
A3
248
This result ofthe forecastis highly encouagirg. It promisesa new hope. Giveo
the proper suppon and cooperationby the Philippine Gov€mmentand its people, the
Philippine oocodile may oace again bouace back and tbdve in some of their former
hsbitats.
t29
FUTI'RE PLAI\IS
. Comprehemive
Rcserrchstrd ManrgeBentPLNtr
Obiective;
of
To orgalize a conc€r:t€d
efort towardsthe conservationand management
Crccdylw ninfuen$is bothin captivity(farms,privatecollectiors,zoos,andresearch
institutions)andin thewild.
$!spe.sf
.WeruAeliv4ie!:
aI crocodilesin captivityi.e.fams, privatecallections,andzoos
1. Register/Invedory
level;
natiooal
and
iftemationa.l
at
2. Establish
a nationalwo*ing committee
wbichwill tacklematte$andcoucemsabout
its farmingconservation
managemeirt,
andresesrch
anddevelopment;
3. Est8blidla criteria"nt€s and regulations8boutac4uiringcrocodil€sfor vanous
purposesi.e. sciertifc researcb,collectio&exhibitio4 and othersin relationto
relatedlaws,ordirunces,
andsdmidsttatiooord€rsandpolicies;and
4. To s€rv€as an advisorybodyto the ProtectedAreasandWildlife Bureauof the
related
Department
ofErNirotroetrtandNaturalResources
on rDsttgrs
andconcerDs
to crocodilemsnsgem€oL
. Estrblishmentof CmcodileSanctuary
Obiective:
To cons€ryecrocodlesin their naturalhabitatpref€rablyin dedar€dprotected
areas.
Scopcof Activities:
l. Coduct populationsurveys;
2. Conductssilctuarysrdtabilityass€ssoent;
of
3. Cotductinfoflnationand€ducstioncanpaigtrto promotetlle socialacceptsbility
establislm€nt;
crocodilesanctuary
4. Cotrduotcornmunity
organization
andpublicrelationworks;
5. Seoretheapprovalofthe projectfrom theProtectedAr€ Management
Boardofa
panicularprot€ct€dare4,ad
6. Re-stockandrtro[itor aod m'nagethe oocodilepopulationin thesarctuary.
130
. Vcrilicitiotr Survey8|ld Actud Erbitat Surveys
Obiective:
in theirh8bitstsbasedon the
of remmtrtcrocodiles
To veri&/codm thepres€nc€
historicalatrdcurr€lt sites.
Scopeof Activities:
in theirknownhabitats;
ofcrocodilesightings
1.To onceagainved$ tbepresence
2. To confifmcurent verbalreportsaboutthe presencrof crocodilesitr somelesse!
lnown habitatsh tl|e coudryl
systemofreportirEachlalsighhgs;
3. To comeup with a sci€nt'lfic
4. To sulisy al1drssessthe viability of habitatarcaswith confirmedcmcodile
PoF atio[ 8trd
pla! in viablehabitats.
5. To proposeanactionald nanag€ment
* o,Con[erciNl Specics
. Rcgfutrrtionof 6ooo4t ns minilorensis
9bidi4e:
To register with CITES as a cosoerci4l captive breedingoperationfor
Crocdylusminbensis uPontheproductiooof Fr gelerationh captivity.
Jusifcatioru:
since
8d captivebrcediogfacilityhasbeertFoducilg the species
1. CFI asa research
1989:
2. TbatpureF2gentrationwill soonbeproducedusingF1brceders;
:. fUt iustainableutilizationof C. mindqensisas a commercialspeciesuill help
peopleto participate
coniervationin thecoustryasit will €trcoutage
€osuiespecies
importance;
andeconomic
andsupportprojcctswith environmental
l. Tharprojectedpopulationwil only be attainedlf C. ninfurensis zte farned out;
ard
to
s. That a cerrainftactionof captivebredwill be usedto restocksanctu3ry/ies
restorewild population.
131
BIBLIOGRAPFY
Aquino, M.T.R. 1998. Surgical Rsrnoyal as Treatment for Uosbsorbed Yolks in
Hatchlirgs Prcduced at the Crocodile Fsrming lllstitut€. Unpublished Report.
CrocodileFarmingInstitute,Puertohincess City, Palara{f philippiDes.
Aquino, M.T.R. 1998. Use of CyanoacrylsteMhesive for Skh Closure in Crocdylus
mindorensisal|d C- porovs, UnpublishedReport. Crocodile Farming Institute,
PuertoPrincesaCity, Palawa4Philippines.
Coher4 M.M. and C. Gans. 1970. The Chromosomesof the Order Crocodilie
Cytogenetics.
9:8l-105.
Dia4 J.L. 1992.Pers.Com.
JanerlarL M.L.M. 1993. Utilization Sch€mc: Ar Approach to the Conservationof
Crocod/us mindorensis and ihe Role of CFI in lts Implementation. Second
Workshopto Reviewthe lterDs,Objectiv€sandOperationofthe CFL pp.2426.
Lin8a, M.G.C. 1995.Prelihinary Observationson the FeedingBehaviouras Displayedby
Juvenile and Hztcifing Crocodylus mindorensis. Unpublishedreport. C.ocodile
Farning Institute,PuertoPdncesaCity, PElawarlPhilippines.
Ling4 M.G.C. and M.G.C. Malolos. 1996. Determinatio! of Amino Acid in Crocodile
Me3t and SomeCrocadileFeeds.Unpublishedreporr. CrocodileFarminghstitute,
Puetto PrincesaCity, Palawan,Philippines.
Malolos, M-G,C. 1995.Determinationofthe PresenceofTwo DigestiveTract Enzymesin
the Two Speci$ of Crccodiles.Unpublishedreport. Crocodile Farning Institutg
PuertoPrinc€s8City, PalawarlPhilippines.
Malolos, M.G.C. and M.G.C. Linga" 1996.PreliminaryAssessmentor the Use of Snail
(Aclolirrartiica) 8s Mineral Supplene to Die/rsof Crocdllxs poros,rs urd
S!|c1,I
C. mindorensisE*cbJtngs,Unpublishedrcpon. CrocodileFaroing hstitute, puerto
PrincesaCity, Palawa4Pbilippir€s.
Malolos, M.G.C., M.G.C. Linga and B.C. Asuncion. 199?. Comparative Growth
Petformznoeof Crocdylus poroots atd C. mindorensisHatchlirgs Utiliing Mx€d
FeedRarion.Unpublishedreport. CrocodileFarning lnstituie, PuertoPrincesaCity,
Palawar;Philippines.
Malolos, M.G.C., M.G.L. Abiog and B.C. A$noion. 1997. Protein Requirementsof
Ctocdylus porons andC. mindorensisHatclrltngs.Uryublilhed r€port. Crocodile
Faming Institute,PuertoPdnces8City, Pslawalr,Philippines.
t3z
Malolos, M.G.C.andR.S. Eliven. 1995.Determinationof Mnimum vitamin Requirement
of Croe'(dius mindorensisa^d C. porosas.Unpublishedreport. CrocodileFarming
Institutg PuertoPrincesaCify, Palawa4Philippines.
Marais,J., G.A Smith ad B.D. Borgelt. 1994. The ReproductiveEftciercy ofthe Nile
Proceedingsof the lZd
Crcr:;cldile(CKEdltus niloticus) 1n Southern Afica
Working Meeting ofthe CrocodileSpecialistGroup. Pp. 256-265.
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Workshopon the Prosp€ctsand Future Srategy of CrocodileConservationof the
Two Species(Crocodylusmindorensis,C- porosxr) Occuning in the Philippin€s.
Pp.98-10t.
Milar! V. 1995. PalananWildemessReserveCrocodiles. Perscorn
Onega, G.V. 1993. Conservatioq Mansgemert and Farming of Crocodiles in the
Philippines. Proce€dingsof the 2- Regional (Eastem Ash, Oc€ania,Ausralia)
Meeting ofthe CrocodileSpecia.list
Group pp- _
OrteSa.G.V. 1998. Crocodile Conservationand Fanning in the Philippines.Presented.
95'Philippine VeterinaryMedicalAssociatioaConvention.DEvaoCity, Philippines.
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Conventionon Statisticspp- _
Ramirez,R. 1993. TuguegaraoCrocodile.Pen com,
Regoniel,P-, U. Pontillas et d. (1991). Distribution and Status of Crocodiles in the
Provinc€ of Palawan, S€condWorkshop to Reriew the lterns, Objectiv€s and
Operationoftie CrocodileFarmirg Institute. pp. +10.
Ross,C.A 1982. Final Report on S.LAff.W.F.Project No. 1489. PhilippineCrocodil€.
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Ross"c.A and A-C. Alcala. 1983. Dstribution atrd StEtusof the Philippine Crocodile
(C/@dyl6 mindorensb\ Phil. JoumslofBiology 12(ll2) : 169-173.
Sarsagat,I.G., Sibd, M.C. 8od Setake, Y. 199. Rearing of Crocodil€s h CFI.
Proceedingof the Workshop on the Prospectsand Future Strategy of Crosodile
Conservationofthe Two SpeciesOccuning in the Philippines.pp. 24-35.
Sibd, M.C.,I.G. Sarsagatand Y. Satake.1993. ComparisonofRearing and Breedingof
Crocdius nhdorensis and C. porosns in Captivity. SecondWo*shop lo Review
the I1€m3,Objectiws nndOpe|8lior ofthe CFI. pp. 12-20.
133
Sumagsys8y,C.V. 1993. Diseases and Characteristio Problems in Crocodylus
mirrdorensis and C. poros s in CFI. Second Workshop to Rwiew the lterns,
ObjertivesandOperationofthe CFI. pp. 2l-23.
Sumilfer, RQ. 1997. Captive Breeding of Crocodylus mindorensis and Crocodylus
porosrr at the CroaodileFaming Institute (CR), Philipphes.UnpublishedReport.
Sum.ifler,RQ. (1998). Captive bredmg of Crocodylus minturcrrsis ard Crocdyhts
poronr at CrocodileFarminglNtitute (CFI), Philipprnes.Unpublishedreport.
Sumifer, RQ. and R.A. Cornel. 1997. Temperature-Depcrdent
Ser(Determinationofthe
Two SpeciesofCrocodil$ (C, mitdorensis urd C-pomvs\ UnpublbhedReport.
CFT.
Sumiller,R.Q. andG.M. Gol-lod. 1998.Effests ofRearing llatcttling-JuvenileCrocodyl6
mitdorensis etya{ious StockingDensities. Unpublisbcdr€port. CFL
TugEs,A 1995. CagayanRiver SystemBukarot Crocodilee.Perscom.
134
CROCODILE
CONSERVATION
ANDDEVELOPMENT
INVIETNAM
Professor
CaoVanSung
Institute
of Ecology
andBiologyResources,
Hanoi,Vietnam
&
RobertW G Jenkins
CITESAnimalCommittee
Canbena.Australia
lntroduction
Sustainable
economicdevelopment
is a politicalimperativeof the Vietnamese
Govemmentand an ever-present
realitythatcharacterizes
the Vietnamof the 1990s.
Indeed,one of the principalmotives,that stimulatedthe Govemmentof Vietnamto
accedeto CITESin 1994,wasthe desireto tradelegallyin captive-bred
specimensof
Appendixl-listedcrocodiles.This paperdescribesthe presentstatusof crocodilesin the
wild,crocodilebreedingfacilitiesand measuresfor the protectionand developmentof
theseresourcesin Vietnam.
The CrocodileResource
Two speciesof crocodiles- the saltwatercroc'dile(Crocodylusporosus)and Siamese
crocodile(C/ocodylussiamensi9 occur naturallyin Viet Nam. In the past the saltwater
crocodileoccunedmainlyin coastalestuarinehabitatsfromVungTau to KienGiang
Provincesin southemViet Nam,and in Con Sao,Phu Quoclslands.This speciesis
greatlyfearedby peoplewho flsh in the riversand swamps.Overhunting
and habitat
losshaveresultedin a seriousdeclinein the numbersof C. porosus.Accordingto
huntersand localpeoplethe numbersof this speciesin the wild are lessthan 100
animals.Crocodylusporosuscan exceed4 metresin length. Femalesdeposit25-50
eggsin a nestconstructedof driedand rottengEss and leaves.The saltwatercrocodile
is regardedas endangeredin Viet Namwithonlya smallnumberof solitaryindividuals
remainlngin remoteforestedareasof Uminhswamp.
The SiameseCrocodile(Crocodylus
siamers,s)is distributedin suitableinland
freshwaterbodiesin southemand centralVietnam.This speciesis commonand
distuibuted
in riversand deepstreamsthat persistthroughthe dry season.The species
concentrates
in deeplakesand pondssuchas Lac Lake,upperKrongPachLake
(SaclakProvince),crocodilepool(KhanhHoaProvince),CrocodileSwamp(Songnai
Province).This speciesis abundantin Vietnam.lt has beenestimatedthat
approximately
200 animalsstilloccu[in TaysonLakeand about2000in Lac Lake.
Althoughis seemsas thoughCrocodylus
s,bmers6continuesto existin the wild,the
pressuresof an expandinghumanpopulationand the associaiedlossof habitathave
seriouslyaffecledthe distribution
and populationdensitiesof this species.
Bothspeciesare believedto persistin areasof suitablehabitatwithinprotectedareasin
southemand centralViet Nam(Figure1), howeverthe exlentto whichtheseareas
receiveadequateprotectionand the leveland mannerof management
that is being
lJ5
appliedthe by the ForestProtestionDepartment
is unclear.Populationsof bothspecies
of crocodilesin Viet Namare underconsiderable
and increasingpressure,especially
giventhe transitionaleconomyof the countryas it developsintoa free marketeconomy.
Populationsin the wild continueto declinedue to huntingfor meatand exportof skin.
Suitableriverinehabitatis contractingas a resultof logging,urbanisation
and vegetation
clearancefor plantationforestryand agriculture.The conservation
of wild populationsof
C. siamensisand C. porosr.ts
and effectivemanagement
of crocodilebreedingfarmshas
becomea problemfor Viet Namthat requiresthe development
and applicationof policies
strategies
and
for effectiveimplementation
of CITESthat are tailoredto suilethe social
and economicconditionsthatcharacterise
Viet Nam.
ln '1985a groupof 100CubaCrocodiles(Crocodylus
hombilei wereimportedintoViet
Nam as a gift fromthe CubanGovemment.Becauseof the absenceof any single
facilitycapableof housingtheseanimals,the Govemmentof Viet Namdistributedthe
animalsto differentfarmsfor breeding(HanoiZoo,SaigonZoo, Da Nang,Ca Mauand
Nha Trang). The housingfacilitiesof mostrecipientsare poorand are not suitabletor
breedinglhis speciesand the survivingspecimensoriginallyimportedremainas solitary
animals. Nevertheless,
severalestablishmenb(e9 DongTam ReptileBreedingFarm
and SalgonZoo and BotanicalGardens)have managedto breedthis specieswith the
natjveC eamensisto producehybridprogeny.AlthoughSaigonZoo has retainedall
hybridprogenywhichare presentlyon publicdisplay,the reportedpresenceof hybrid
animalson somecrocodilefarms(Gozula, 1997)is evidencethat somehybrid
specimenshavebeendistributedamongthe networkof developingfarms.
The viewexpressedby Gozula (1997),that thereis littlelikelihoodof thesehybrid
crocodilesescapingand becomingestablishedin lhe wild and representing
a lhreatto
the conservation
of existingpopulations
of C. s,anensis,is supported.In the unlikely
eventof escapesfromcrocodilefarms,it is exremelyunlikelythat the escapeeanimals
wouldsurvivebeingcapturedor killedby localpeople. Furthermore,
the majorityof
crocodilefarmsare locatedwithinreadycommutingdistancefrom Ho Chi MinhCity.
Noneappearsto be locatedin closeproximityto areaswhereC, siamers,sis knownto
Dersrst.
ft is not clearwhetherany specimensot siamensishhombiferhybrids
have reached
reproductive
maturityorwhetherthesehybridsare maturebut sterileand thus incapable
of producingsecondgenerationprogeny.However,it is very importantto documentthe
presentdistuibution
of hybridanimalson existingcrocodilefarmsparlicularlyfromthe
standpointof managingthe futuredevelopmentof crocodilefarmingin Vietnam,
particularlyif the Govemmentintroducesa re-stochngprcgramto augmentwild
populationsof C. siamensis.The responsible
authoritiesshouldundertakena surveyto
identifyand documentthe presenceof hybridsand isolatingthemat pure C. s/amersis.
The CrocodileFarmingInduslry.
Commercialcrocodilefarmingin Vietnamis restrictedto the warmerand morehumid
climateof southemand centralVietnamfTable1).
136
Table 1. CrocodileHoldingFacilitiesin Vietnam
FaciiitV
Ca mau town
Thot not
Can tho town
Tayninh
La nga
BuiVan Do
SongTam
Vinafor
Thu Duc
SuoiTien
Sai gon Zoo
BinhQuoi
SamSen
Can gio
ThanhThuanFarm
Truonoson
*** Breedingfarms
Location
Ca mau
Cantho
CanTho
Tay Ninh
SongNai
An Giang
TienGiang
SongNai
SongNai
HCMCity
HCN4
City
HCMCity
HCMCity
HCMCity
HCMCity
BuonMa Thuot
Quantity
40
44
100
244
344
30
10
332*400*.
30"'
20
25 (C. porosus)
70*.
30
Captivebreedingof crocodilesin Vietnamis a relativelyrecentphenomenon
and
undoubtedlyreflectsthe transitionof Viet Namlowardsa free marketeconomy.
Crocodilefarming,as curenUypractisedin Viet Namis broadlysimilartothe farming
modelthat hasevolvedand applieduniversallyby all countriesthat breedcrocodilians
in
captivity.The development
of and dependenceon familyoperated"satellitefarms"as
ancillaryrearingand/orbreedingoperationsis an adaptationthat providesimmediate
revenue.This management
strategyhasthe addedadvantageof precludingthe large
food
species
amountsof
thatare requiredfor commercially
efficientgrowthof farmed
livestock.Thereis a thrivingtradebetweenfarmsin livehatchlingCrocodylussiamensis.
Specimenscommandas muchas USD100each. Breedingfarmsregularlydisposeof
'satellitefarms".The
hatchlingcrocodilesio thesecontinuously-establishing
development
of this farmingsystemin Viet Namand neighbouring
Cambodiaappearsto
havebeen heavilyinfluencedby the systemthat operatesin Thailand.
The future devefopmentof the reptile (ie Crocodylussianensis and Pylhon molurus
biyitiatas)breedingindustry,particularly
if the structurethat is evolvingis retained,has
the potentialto producelargenumbersof specimens- well in excessof the quantities
ableto be consumedby the intemational
market.The commercial
viabilityof reptile
farmingreliesof maintaining
a highunitvaluefor the productthat is beingmarketed.
Over- productionwill undoubtedly
resultin a reductionin the unitvalueof the marketed
produc.ts.In keepingwiththe politicalpriorityof lhe VietnameseGovemmentto achieve
sustainableeconomicdevelopment,
the industry,in collaboration
withthe Forest
ProtectionDepartment,
mustaddressthis issuethroughlong-termstrategicplanning
eitherto limitoverallproduqtion
of commodities
or develoonew exDortmarketsfor a
broaderrangeof prcducts.
ln January1998,at the requeston industryrepresentatives,
the Ho Chi MinhCityoffice
of the FPDconveneda meetingof interestedreptilebreedersfor the purposeof
assessingthe feasibilityof formingan industy association.At this meeting,the decision
was takento establishthe Association
of VvildlifeBreedersof Vietnamin April 1998.
This decisionrepresentsa positivemoveby the industryand one which,if developed
and constitutedcorrectly,willplayan importantrolein promotinga responsibleapproach
by its membersto the commercialuseof wildliferesources.Thiswill, in turn,advance
the longterm commercial
sustainability
of the reptilebreedingindustry.The association
plansto developa strategicplanfor breedingindustryfor marketingproductsin accords
with the principlesof sustainableeconomicdevelopment.
Conservationof crocodile in Vietnam
The crocodilepopuiationin Vietnamis underconsiderable
pressureThe numberof
animalsin the wild declinesyearlydueto huntingfor meatand exportand habilatlossby
loggingfor plantationand agriculture.The conservation
of crocodilesin the wild and
managementof crocodilefarmingmanagement
in Viet Nampresentsa problem
concemingpolicyand strategyof natureprotectionin Viet Nam. Nevertheless,
the
VietnameseGovemmentis committedto protectand conservenaturalresourcesin
generaland crocodilesin particular.
Legislationand Administration.
The conservation
and management
and management
of wildlifein Vietnamis the
responsibility
of lhe ForestProtectionDepartment
(FPD)withinthe MinistryofAgriculture
(MARD).Viet Namaccededto the Conventionon Intemational
and RuralDevelopment
Tradein EndangeredSpeciesof Wild Faunaand Ftora(C|TES)on 20 January1994.
When accedingto CITESthe Govemmentof Viel Namnominatedthe Forestproteqtion
Departmentas the CITESManagement
Authorityand two Hanoi-based
research
institutesas the CITESScientificAuthoritiesof Vietnam- the Instituteof Ecotogyand
BiologicalResources(IEBR)and the Centrcfor NaturalResourcesand Environmental
Studies(CRES)ofthe VietnamNationatUniversity.
Thereare severalseparatelegalinstruments
by whichthe Govemmentof Vietnam
regulatesthe use of nativewild plantsand animals.
. GovemmentDecreeNo.77of 29 November1966on ForestManaoement
and
Protectionand Management
of ForestProducts
. Law of 12 August1991on ForestProtectionand Management
. CouncilofMinistersDecreeNo.18of 17 January1992on the Management
and Protectionof the Listof PreciousPlantsand Animals.
. MARDCircularNo.13of 12 October'1992on Guidelinesfor lmDlementation
of
Ministers
DecreeNo.18.
. GovemmentDecreeNo.62of 5 January'1995on conditionsfor Tradeand Non
- Tradein PreciousPlantsandAnimals,Theirpartsand Derivatives
(Commodities)
. MARDCircularof 5 February1996on Guidelinesfor lmplementation
of
GovemmentDecreeNo 62
138
. PrimeMinisteriallnstructionNo 359 of 29 May 1996for the Protectionand
Development
of V\'jldPlantsandAnimals.
. FPDOfficialNotification
No.280 of 25 October1996on Captureand Useof
GroupI and Groupll PlantsandAn;mals.
The presentlegislationavailableto the CITESManagement
Authorityis considered
adequateto regulatethe crosodilefarmingindustry.Bothspeciesof crocodilenativeto
Viet Namare classifiedas GroupI preciousspeciesunderthe Councilof Ministers
DecreeNo.lS of 17January1992.Ar clelll of DecreeNo.18prohibits
huntingof Group
I species.Sectionlll of FPDCircularof 5 February1996,(whichjmplements
GovemmentDecreeNo.52of 5 January1995),prohibitsthe exportof GroupI species.
Thisexportprohibitionis reinforcedby SectionlV of the FPDOfficialNotification
No.280
of 25 October1996whichprescribesthe conditionsunderwhichGroupI and ll animals
may be farmed. lt ppvides for the FPDto permitthe useof thesespeciesfor
development.All oiher usesrequirethe permissionof the Ministerfor Agricultureand
RuralDevelopmenl.The FPDappearsto possessthe authorityto inspectfacilities
(ArticlelV of MARDCircularNo.34of 12 Ostober1992refers).The FPDis requiredto
registerwildlifebreedingfarms,issueeachestablishment
with a stockrecordbookand
conductinspectionsof registeredfacilities.However,the FPDneedsto implementa
standardised
systemof recordkeepingand enforcecomplianceamongwildlifebreeding
farmsin Vietnam.
The breedingfarmsare requiredto accuratelyrecordinventories
of newstock(eggsand
birlhs,acquisitions
and disposals).The responsible
authoritiesshouldcontroland
monitorrclevantdocuments,stockrecordsand livestock.The CITESManagement
Authorityof Viet Nam(FPD)andthe CITESScientificAuthorities(IEBRand CRES)are
responsible
for moniloringand controlling
all crocodilefarmingactivities.These
organisations
also cooperatein applyingmeasuresto protectthe resourcein the wild.
Domesticationof crocodile.
Crocodilefarmlnghasthe potentialtomakea signific€ntcontribution
lo the Vietnamese
economyand "domestication"
of crocodilescommencedduringthe Frenchcolonial
oeriodfor the oroductionof crocodileleather.The fishermancatchcrocodilesfrom the
wild and raiselhem in cagesand pools. Crocodileswerekept as 'backyard'animals.
Privateholdingfarmsbecamepopularin SouthVielnam,especiallyin MekongDelta
areaand crocodileslocksreachedmorethan2000animals.Consequently
manyof the
present-day
tarmershaveacquiredsomeexpen'ence
oil produstion,hatchling,nursing,
feeding,leatherproductionand marketing.Theseactivitieswill formthe basisfor a
futurecommercialindustry.In this respect,itwill be importanttoharmoniseexploitation
and conservation.
The Govemmentof Vietnamplaceshighpriorityon the conservation
of naturein general
and crocodilesin particular The Govemmenthas promulgated
regulationsand decrees
for habitatprotection,prohibitionof huntingand tradein animalsfromthe wild. As
mentionedabovethe Govemmentof Vietnamconducteda meetingof crocodilefarmers
and interesledreptilebreeders.The meetingprovideda forumfor the exchangeof
r39
informationon captivemanagement
and productionof reptiles,as well as establishing
closecooperationbetweenscieniistsand farmers.
Vietnamhas establisheda systemof protectedareaswhichhas developedfrom 87 sites
in '1986to morethan 100 in 1997. Eightof thesesitesprovideimportantwetlandhabitat
and prolectionfor crocodilepopulations(egYok Don NP,CattienNP, KrongPachNR,
Sa Thay NR,Tay Son NR, Lak Lake NR,Ca MauNR,Can Gio CulturePark).
Naturalresourcesare viewedby the Govemmentof Viet Namas playingan important
role in the sustainableeconomicdevelopmeniof the country.Accordingly,
the
Govemmentof Viet Namhas adopteda policyof harmonising
exploitation
and protection
of crocodileresources.The crocodileraisingin SouthViel Namis developingand
increasingincomefor localpeople.Viet Namaccededto CITESin 1994and desiresto
tlade legallyin captive-bred
specimensof C-slamersisaccordingto the provisionsof
CITES. Forthis purposeViet NammustenforcerelevantlegislativerequiremenG
for
breedingfarmsto maintaindetailedrecordsof farmedcrocodiles.
The breeding
operationsmustcomplyfullywiththe directionto supplyinformation
on lhe operatjonand
livestockand satisfyall the requirements
of CITES. Viet Namshouldensurethat a
strongpositiverelationship
betweencrocodilefarmingand conservation
of wild
populationis establishedand maintained.Forinstance,the crocodilefarmingindustry
needsto be strictlymanagedto ensurethat produclionsystemsare restricited
to pure C.
s/bmeas/ssuch thatfarmedstockcan be usedas a sourc€of animalsthat is ableto be
usedin any restockingprogram.
Remarksand recommendations.
Crocodylusporosusa d Crocodylussiamersis are knownto persistin Viet Nam in areas
of suitablehabitat. Howeverbothspeciesare cunentlylistedin the endangered
categorywith a highpriorityfor conservation
action.
Crocodilefarmingin Viet Namis still largelyin developmental
phaseand many
operationshave not yet achievedcaptiveprgductionof crocodiles.Howevercrocodile
farmingfacilitiesin Viel Namare generallygood. ln the nearfutureViet Namwill prepare
a documentto reglsterselectedcaptivebreedingoperationswiththe CITESSecretarjat
in accordancewith ResolutionConference8.15.
. Viet Namshoulddevelop,for consideration
bythe CITESadministration,
a proposalto
population
undertake
surveysto assessthe statusof bothspeciesof crocodilesin
areasof suitablehabitatin Southand CentralViet Nam.
. When registeredwiththe CITESSecretariat,
the CITESManagement
Authorityof Viet
Namshouldensurethat all registeredoperationcomplywith CITESrequirements
and
that a systemof regularinspections
is implemented.
. Viet Namshouldcollaborate
with intemational
institutions
and organisations
in
obtaininginformation,
technologyand fundsfor developlhe potentialviabilityof
crocodileeconomyin Vietnam.
l4{)
Curretrt Statusof Crocodile in Cambodia itr Captivity and itr the Wildr
Nao Thuol, D€puty-Directorof Filberies;
No. 186,Preal Norodomboulev?r4 ChancarMo4 P. O. Box 582,PhnomPeDb,Cambodia
Abstract
The Kingdom of Cambodia is home to two endemic crocodile species,the
Frcshwateruocodile (Crccodylus siamensis)aJ]rd,
the Saltwater aocodile (Crodylus
poro*s).'fhe formeris still presentin the wild in 14 provincesall over the couotryand
is widely bred in captivity in 8 provincesalong the rivers and esp€ciallyill and around
the Tonle Sap Great lake- Whereas,the latter iDhabit the estuarineareasfar from
human settlement.It is thought to be nearly to extinct with few specimensbeing
sightedin the coastalareas.
Wild qocodile conservationis hamperedby the lack of awarenessamonglocal
communitiesand other stakeholdersbecauseof the long run civil war that caused
overall poverty in the country. While Freshwatercrocodile faming the majority of
which are small scale develop rapidly becauseof its economicviability in the early
1990s.
Srnceafter the general election in 1993, Carnbodiahas accededto several
ifiemational conventions,especiallyrccendylast yearto CITES.At the meantimq the
local marketis saturatedwhich may atrect futue devclopmentofthe country aswoll as
the nationaleconomy.
This coutrty paper prese[ts the statusof crocodile consgrvationin Cambodia
and higllights the marketing problem of farmed crocodile skim and deriwtives that
carupt be exportedarising ftom the country's late aacessionto CITES-It also rcquests
the on-goingassistanceofthe CITES Secretariatand coopention of inlerestedParties
to enable the Governmentof Cambodia to develop the necessgry.u[derstanding
technical and administ'ative capacrty.to dischargeils obligation as a Party to the
Convention-
l@csl&!
Carnbodiais a low-lying country locatedalmost entirely in the catchmeotarea
ofthe lower Mekongbasin.During the monsoo4 the Mekong feedsinto the Tonle Sap
Great Lake causingthe flow of the Tonle Sap to revelse. The Mekong4rcat lake
system createsa vast iDland water bodies compdsing numerousrivers, lakes and
permanontpotholes cxtcnded into flooded forests, grasslan4 ricefields and swamps
(Anmedet al., 1996).
I Contribtrtionto the l4th working Meetingofthe crocodile specialistc'roup in Singapor€,t4-17 July,
1998
l4r
The inladd \iater bodiesof Cambodiaespeciallythe Tonle SapGreatLake are
famousin fish productionin SoutheastAsia (Bardach,1959)which constitutesa good
soulce of feed for crocodilian speciesto inhabit permanentlake and flooded forest
aroundthe Tonle SapGreal Lake andalongthe Mekongfuver as well as in the upland
water bodiesin the mountainousregionsborderilg the centralplainTwo speciesofcrocodile are endemicto Cambodia:th€ Siameseor freshwater
croc'odile(Crocodylussiafierais) and the Saltwater crocodile (Crocodylusporosus).
The former is still largely distributedin the wild around the Tonle Sap Great Lake
region and along the Mekong fuver. They are also being largely bred in caprivity in
many provincesaroundthe Great Lake. While the latter is reportedly to inhabit rhe
coastaland estuarineareasfar ftom humansettlementin Koh Kolg govince. Chu Ta
Kuan, a Chineseobseryerto Cambodiain the 13th century appreciatedthe natual
resourc€rich ofthis country includingqocodiles (SiamSociety,1992).
Cambodiabegandomesticatingcroaodilessince the loth century, a little bit
before the Angkor time. The Westem Mebon ruin of crocodile pen in the Baray
reservoirin Siem Reapprovinceis a legacy.But commercialcrocodile farmingswere
operatedin around1945dudngthe Frenchcolonial time. However,this businesscould
not developvery much becausetha governmenthadnot issuedany speaificstrates/ or
planfor development
As a result ofpoor management,
crocodilepopulationhasbeenexploitedto the
brirk of its sustainability and became enda:rgereduntil nowadays. To consewe
crccodile from being over-exploited and beiog extinct, and to contol crocodile
farming the goverDmenthas issucdthe Code of Fisheriesand regulationsduring the
1940sbringing crocodileunderconselvationAffer the collapseofthe Kbmer Rougeregime,the Fial-law no. 33 of9 Ma&h
1987,confnes the managementand conservationof crocodile under the responsibility
ofthe FisheriesDepartmentofthe Ministry ofAg-iculture, ForestryandFishedes.
2. Crocodile Colservation Elforts
IIr the pastcrocodilesinhabit nearlyevery importantwater body ofthe aountry.
Mady places and v€ter bodies were named related to qocodile existenceand its
activities.In the GreatLake andalongthe Tonle Sap ver, one hasto be cautiouswhen
fishing or navigating.
As human settlementdeveloped,habitat encroachrnentalld hunting put more
pressur€on qocodiles and put them to the brink of thek home range. As the skin
busin€ssincreased,crocodileswere huntedheavily and becameendangeredresulting
from poor management
that hasbeenpaidto this keystonespecies.
t42
To deal with the decline in crocodilepopulationand to protectthem from being
over-exploitedand extinct, the governrnenthas issuedthe Code ofFishe.ies during the
1940sto strictly prohibit indiscriminat€crocodileexploitation.
During the genocidal regime of the Khmer Rouge, all fisheties management
activities were abolished.There was a totally op€n accessnature for all iesouces
without limit. The then Khmer Rouge govemrnentappointedmany groupsof fishers
with the only appointedduty to fish to supply the then farmers'cooperatives.It is
wonhwhile to notethat, during that time, no one could gel accessto fishing unlessthey
faceddeathpenalty.
The Fisheries Fial-Inw enacted irl 1987 is one step back to crocodile
conservationin which it is stricrly prohibiredall activitiesrelatedto catchingcrocodile.
Article 19 definesclearly the needfor permit to establishcrocodile faIm and article 18
strictly Fohibits catching selling,trarEponingofcrocodile and 3 more endangeredfish
speciesunlesssp€cialpermissionftom the DepartrnentofFishedesis provided.
Also with the conceptof qocodile and other wildlife conservation,Cambodia
aftendedthe Earth Summit in Rio de Janeiroin June 1992and ntified the Convention
on Biological Dive$ity on 29 February 1995. Ac..€ssion to the Convention on
Intemational Trade in EndangeredSpe{ies of Wild Fauna and Flora (CITES) on 2
October 1997, rcpresentsa fifther expression of the Cambodian Govemment's
courmitmentto coDserveits naturalbiological diversityand manageits componentsfor
sustainableuse. For conseladon re:rsort'on the lst day of November 1993, King
Norodom Sihanouk promulgateda Royal Deqee designatingprote{ted and mulhpurposeuseareasencompassing
rnanyofthe procodiledistribution area However,tlds
Royal Decreeleft manycrocodilehabitatsoutsidethe protectodzones.
In additiotrto thc effon undertakenby tlle Govemmentside' clocodile farmers,
with the leadingactivity ofthe author in 1995,haveunited and formed the "Crocodile
Farming DeveloporentAssociationof Cambodia"-Furftermore,they have conunitted
to contribute a rcasonableamount of money to undertake surveys and rcgular
monitoring activities.h addition, they are willitrg to keep3 to 5% of their productron
to releasebackto thg nabral habitatsto co ribute to the conservationof the sPeciesin
the wild
3. Presert Statusof Crocodile Populatior itr Cambodia
Although the DepartrneqtofFisheries, as the goverulert authority responsible
for the managementof crocodile in Cambodia,employs qualified biologists, no
scientifically-basedquantitativesurvels have beenundefiakel to determirc the s|ze
and distribution of either speciesof crocodile in Cambodia.The absenceof scientific
d,l.!aon Ctocodylussiarzensisin Cambodiahas treendue principally to the more than
two decadesof war and intemal conflict that has characterizedCambodiasince the
early 1970s.Many regionsof Cambodiawhere Crocodylussiamensisar.dCtocodylus
porosus are believed to persist have been unable to be surveyedby govemment
143
officials becauseof the Khmer Rouge.Even in more recentyears, when the territory
held by the Khmer Rougeguenillas in Cambodiabecamecontractedto the northwest
oflhe country nearthe Thai bordel it remainedur$afe to visit many areasbecauseof
the danger of detonated unexploded ordinanc€. The political imperative of the
CambodianGovemmentto manageand useits fishery resourcesfor the benefit of tlle
Cambodian people and economic development of the country has dictated that
availableresourceswithin the DepartmentofFisheries be allocatedto developingand
managingcommercialfisheries.Thesefinancial resourceshave not been adequateto
underfakeresearchandother management-related
activities on crocodile in the absence
ofany legal exporttade.
3. I Distribtrtiott of CrocodylussiarE tsir in the wild
Historically, Croco$tlus siamehsis occwrcd in ar€as of suitable fieshwater
habitatthroughoutCambodia,neighboringThailand,Lao PDR and Vie&ram.In rec€nr
years, specimensrcsemblingthe specieshave been found to occur in the Indonesian
province of East Kalimantanon the island of Bomeo (JeDkins,1998). The identity of
utimals identifredasCrocodylussiamensisrcpoied in the literatureas occuring in the
lrdonesianarchipelagorequircsfilnh€! studyandclarification.
Although thereare no scientific ddtaotl nurnberofcrocodiles in the wil4 th€re
ale many placesof suitablewetlandhabitatremainard it is widely known amongrual
fishing commrmities and regional fisheries officers that Crocodlius sianensis is
presentin many of theselocations.Many sightingsofjuvedle animals are reportedto
provincial fisheries ofrcers annually by fishermen. Based ol advice information
obtainedfrom mrmeroussources,Thuok and Tana (1994) concludedthat the species
persistsin remote arcas in about fourteen(14) provinces (seetable I ad figure l).
Many ofthese areascoincidewith the extensivenetwo* of Fotected areas(seefigure
2) that have been establishedin Canbodia in accordancewith the Royal Decreeno.
126of I November1993on Creationand DesignationofProtected Areas.The present
siz.eand trendsofthe populatior is not known. Nevertheless,Croco@/zssiamensisis
regardedas an endangeredspeciesin Cambodiawhich must be studiedto ensurethat
this resourceis managedproperlyand conserved.The proposedrcgistrationofselected
crocodilefarmsandthe developmentofa legal exportfade in skins and otherproducts
derived ftom farmed.Crocodyltts siamensis,withir. the ftamework of CITES, will
provide the nec€ssaq.economic and political incentives for the Govemment of
Cambodiato investin field studiesandmonitoringfor the speciesconservation.
The Departmentof Fisherieshas obtainedthe commitnent of the Crocodile
Faming DevelopmentAssociationof Cambodiato allocate fimds for undertakinga
srwey programmeof a wild populationsas a fiIst step to establishingan oFgoing
monitoring programme.Revenueobtainedfrom the legal export of famed crocodile
skinswill providethe necessaryfinancial incentivefor the industrycontribution.
144
Table 1 Distribution aod Estimated Number of Crocodvlussian znsis itr Cambodia
No.
t
2
3
5
6
Provitrce
StungTreng
Battambfis
SiemReap
KompongChnang
KomDonsThom
KompongSpeu
Estimated
Eabitat types
numbers
3.000-4-000 SekongandSesanregions
1.500-2.000 Floodedforestin lots no.1-2-3-4
1,000-1,500 Floodedforest in lots no. 1-2-3-4-67.
200-300
Floodedforestin lotsno. l-2-3
150-200
SeineStrgamResion
150-200
Triangle rcgion of 3 provinces
Pursat Koh Kong and Kompong
Speu
7
Pursat
200-300
8
9
KomDonsCham
80-100
50-100
l0
Koh Kone
SvaYRietrs
Kandal
Kratie
PreahVihea
Floodedforest in lots no. l-2-3-4-56.
1l
t2
13
t4
Kampot
Fishinslot Do.2
AJ ongvil, Prck Krieng and Stung
Kach
300-500.
Mondol Sevmadistrict Kbal Chhav
4-20
KomoonsTrachriver
10-20
PrekPhnouv
80-100
Chhlong
2,000-3,000 Swampy areas near Thbeng Mean
Chev
According to the ioformation given by peoplefrom Koh Kotrg provinc€,some
Salt water crocodilesTCrocodylus
porosu) te sttll inhabitingthe coastalandestuarine
areasof Koh Kong p.ovirce. Apart from the wild population,4 bezd of Croco$iw
porosus werc brought to Siem Reap Crocodile Farm for rcsearchas well as tourist
attractionand educationpwpose'
3.2 S'5nts of Ctocodllus Jrorr4zrir in captivity
3. 2. I Backgrourd
Cambodiahas begun domesticatiogcrocodilessince the lOft century as it is
provEdby the West Mebon ruh (crocodile peo) ia WestemBaray-That was Fobably
the rearingofa smallnumberofcrocodiles for leisureby the thenKing's daughtor.
Before 1970,qocodiles was farrned by a numberof fishers in and aroundthe
Tonle Sap Great lake, especially in Siem Reap, Battambatrgand Kompong Thom
prcvinces. But at that time, this kind of industry has be€n lateft becauseof the
authority's neglect.Sofar, thereis no adequateinformationaboutcrocodile laising nor
are there specific raisingstrategissand policies for crocodile raising developmentand
managemert(Thuok, 1993).
145
From 1975to 1979, when the Khmer Rougetook o{f the power, all pdvate
businesseswere then prohibited. All crocodiles werc then gatlered to put into 2
collective farms, the largest one in Siem Reap province and the other in Kompong
Chhnang.
After the enactmentof the FisheriesFiat-Law in 1987 and the free market
economyof the comtry was settled down in around 1988, the priwtization of the
productionsectorwaspromotedwith considerablehasteand private sectorinvolved in
all scales of crocodile farming began to expand rapidly. ln 1989 and 1990, the
increasedmarket demandsfor crocodile resultedin extremelyhigh value of new-bom
crccodiles - a one monlh old baby crocodile commandeda value of USD2-300.
Becauseof its feasibility atrdprofitability, faming of crocodilebecarnevery popularill
many commrmitissesp€ciallythe communitiessurroundingthe Tonle SapGrcat lake
afea,.
The total numberof crocodile faErs in Cambodiain 1997is 429, the majodty
of which are small scale.The total rumber of breedingstock is 3,179 headconsisting
of 2,128 addt females(about half the number of females are still very young) and
1,051adult males (lable 2) with a yearly productionof 13,165offspringsin 1997.The
numberof hatchlitrgsproducedper year is expectedto increaseconsiderablyas long as
the actualrearing slock (6.940sub-adultsjre3chreproductivematurity.
Ratanakom(1992) classifiedthe crocodile farming in Cambodiai o 3 classes,
accordingto numberofcrocodiles kepq the sizeofthe farm andmanagement.
C/ass .1.'Snall scalg small number of crocodileskept in earthenor concrcte
pondsor woodencages.This classis the majDrityandmaybecaUed' family farrfng"
becauseofthe small size and small numberof crocodiles.Thereare around386 small
s€alefams in CamMia scatteredalong rivers and around (even in) the Tonle Sap
GreatLake. Many Cambodianvillagers living alongrivers keep l-2 pairs ofbreeden in
an arca at the back of thetu houses.Family scrapsand fish from the dver and lake
provide a good sourceoffood- Fish are either caughtor purchasedat a low price. Some
fishermenwho live on floating housesor boats preferto keep crocodiles in wooden
cagesthat float besidetheir housesor boats.In January,during the dry seasor!adult
crocodilesare tlansfett€d inlo wooden enclosureson dry gound for mating, ngsting
and egg-laying.They are retuxnedto the floating cageswith the onset of wet season
rains when the water level of the lake rises and inudates ttrc surroundinglow-lying
land.
C/a,$ 2.' Medium scale,20-70 animalskept in collective concretepords. These
farms are often locatedclose to rivers or streaEN.This class of fams applies more
sophisticatedfarming methodsoft€n usiog enclosureswhich f€aturc a ooncretepond
and concreteor woodenfenc.es.Crocodilesale housedtogetherin social pondwith l:2
to l:3 male-femaleratio. Nestingmaterialsof sodbroughtfrom the natual habitat are
providedfor nesting-Thereare25 farmsofthis class.
t46
Class 3: Luge scale farms tpically comprising a large areaand number of
crocodilesofmore than 100animals.The breedingstockis kept in consete enclosures
witl concreteponds_Nestingpensare providedwith sod and decomposingvegeration
brought from the natural habitat. Thesefarms hatch crocodile eggs in artificial nests
that imitate natual conditions.During the nestingseason,eggsare collectedearly the
day after laying and re-buriedin the artificial nests.There are only lg farms of this
class.
3. 2. 2 BreedingPerformancein Captivity
Adults qocodiles are kept in social goups for breeding.The male to female
ratio is gen€rally I : 3, although some falmels keep animals as separatepars m
concreleor woodenenclosures.The water depth of eachpond varies from 0.5 to l.j
mefes. Courtship commencesin early Janua4yand may extend to late March-early
April.
In captivity, Clocodylussiamensisreachesreproductivematurity in 6-7 years.
Upon attarningrcproductivematurity, ioitial clutch sizescontain few fenile eggs.The
numberof eggsand percentageof fertile eggsincreasewith the age of female until a
mcan clutch size of 30 is reached.Under favorable mnditioq reproductivelymatue
femalesare capableofproducing up to so'eggsarnually.
Eggs are incubatedas separ-ate
clutchesunder conditions that imitate natural
conditions. Usuallt in the early moming, after eggsare laid, femalx crocodilesare
t'ansfened to anotherpenand the eggsare collectedandremovedto the eggincubator,
being cdeful to retain their origLEl orientation itl the nest. Eggs are placed into 2-3
laye6 into a cavity, apFoximately20-30 cm i{ide and30 cm deep,fhatls excavatedin
the incubatingsoil. Beforeplacing the eggsinto the cavity, a handfirt ofdry leavesand
g|assare placedat the bottomofthe hole. Additional dry leavesandgrassarc plac€dorl
top of the batch of eggs before they are coveredwith a compaciedmound of soil
approximately 15-20cm high. Fach artifiaial nest is separatedby approimately 0.5
metreIncubationoccursin artificial hatcherieswhich are basicallylargewoodenpens
co.ntaining humussoil and decomposedvegetation_This soil is approximatelyI lneae
higher than the surrounding glound. Fggs are placed into cavities that are
approximately0.5 m deepandpackedwith soil into snall mounds.Incubato$ are often
fenced with barbedwire to a height of 1.6 metes. A canal approximately0.5 metle
wide and 0.3 mete deep is dug around the hatcheryto retain water duling the dry
se:tsoll,
Incubatorsare left open to natural sunlight from moming to noon. When it
becomestoo hot, coconutpalm fionts are placedover the incubatorto form a roof to
shadethe nest from dilect sunlightand reducethe temperature.Incubatorsare exposed
to rainfall during the incubationperiod. During the dry season,(especiallyin April) if
therc is no rain, water is spdnkled over the nest and in the canal that surroundsthe
r41
incubator/hatchery.Sprinkling with water increasesthe moisturecontent of the rotting
vegetationand assistsdecomposition.Soil temp€raturesare monitoreddaily (everytwo
hours in Siem Reap Crocodile Farm) by readingthe the.mometerthat is permanently
insertedin the gound at the samedepth as the egg clutches.The iemperaturevaries
'C in April and
between28.5 "C during the first month of incubation (March) to 33
May.
3. 2.3 Eatching
Hatchingtlpicatly occursafter 68-75daysof incubation.when readyto hatch,
the hatchling qocodiles are quite audible when the lest is approached.At this time,
eggs are excavatedand offspring emerge,using their egg tooth to slice the shell
memb.aneand ther puncturethe hard shellfrom the inside.Ila hatchling is not ableto
punctue the shell and.emelgeby itself, assistanceis given by manually cracking the
egg-shell.
3. 2. 4 Neonatehusbandry and management
A.fter hatching, oeotrat€sare washed and tansferred, as a small group of
approximately 30 individuals, into rparate (30 x 60 cm) wooden mrsery cages.
Deformed neonatesand those that have not completely absorbed yolks are kept
'C, util the remainingyolk is
separatelyand exposedto adequatesunlight,at about31
fully absofted
During the fi.st year, especiallythe fiIst two months,baby crocodilesof about
28 cm are very difficult to husband.They suffer stressot shockwhen exposedto loud
noise, bright lighl, temperatue variation gr changesin their diet. Unde! these
circumstances,baby crocodilestend not to eat any food for rnany dals - a condition
which leadsto stuntingin somecases-During the period of cool weather(DecemberFebruary),hatchliogcrocodilestendto eatlitde becauseoflower body temperaturethat
results at this time of the yea!. To ovelcom€this, many farms keep hatchlingsin a
walm eDviroDmentby heading them with charcoal fire stoves or where available,
electic lamps.
Since becoming opentional in the early 1990s,many Cambodian crocodile
fams, in the absenc€ofa legal export tade in skins, havedependedon the saleof live
animals intemally within Cambodiaas a sourceof revenue.In 1989-1990therc was a
high demandwithin Cambodiafor live hatchlingsad a single animal \l'as valued at
USD250- Since that time, with increasingnumber of hatchling being Foduced each
year, tho market for live animals has becomesaturd&d.In 1997,the unit ralue of a
hatchling had declinedconsiderablyto USD20-25.This year again, with very limited
dernand the unit price still goesdown to USDI5-18. Dependingon malket deman4
hatchlingsare sold within 6 monthsof hatching.Famels usedto sell the majodty of
hatchlingsFoduced eachyear - keepingonly a small nurnberof "healthy'' animalsfor
raising drrough to breeders.Thereforc, the moiality was loq ranging from 0J.5o/o
during the first year. Somefarmershave kept 50-100head of hatchlingsfor fanening
148
without experi€ncingany mortality. Among 200 hatchlingskept in Siem Reap
Crocodile Farm, fifteen animals died during the first year - correspondingto 7.j
Dercentmortalitv.
3. 2. 5 Feeditrg
Hatchlings that are fed with freshly-caughtsmall whole fish (sometimelive)
mixed with shrimps, exhibited increasedgrorth during the first 2_3 months after
hatching.The sizeoffish is increasedgradually,as crocodilesincreasein size.During
the secondandthird year,crocodilesare fed daily with as many fish as they are able to
consume.By placticing this feedingtechniqug manyfarmshaverecordedconsiderably
fastergowth lates. Under theseconditions,young docodiles are able to reach 1.2 m
during the fi$t year- someevenreach 1.5m by the endofthe secondyear.At the end
ofthe third year,the meansizpofthe animaisis I.6-l.g m. Somesoecimens
exceed2
m in length.
When the Govemmentmartagedthe two farms in Siem Reap and Kompong
Chlmang growth rateswere considerablyslowerwith animalsonly reaching1.5rn long
after four yea$. This gowth rate wascausedtfuoughpoor husbandrytechniqueswhich
resulted in large number of animals being maintainedin over-crowdedcondition in
small enclosures.
4. Problems Encoutrtered
Regardingthe conservationof c.ocodiles as was statedin the fishery law and
the RoFl Deqee on creation and designationof national parks and reserves,the
govemmentfacesa lot of difficulties in enforcingthe conservationlaw becauseofthe
lack ofawarenessamooglocal commEities and other stakeholders.In this ,esDeclthe
govemmentdoesneedthe panicipation of local comnunities to prot".t -d Lose*e
this valuable resouce. The communitiesalso need some economic incentives from
their participation.
One ploblem arising from crocodile farming developmentis the lack ofreliable
export markets becauseCambodiahad just becomea party to CITES for about 9
months and doesnot have export relation and experienceswith any parties yet. This
problem may hampercrocodile farming developmentin Csmbodia in the firrure and
raay affect the people's livelihood as well as the national economy if skins and
derivativescould not be exponedsoon.
The lack of qualified professiolalsto conductscientific researchesand survcys
on crocodile in the wild as well as in captivity to properly managethis resourceis a
secondconstmintto crocodilemanagement.
149
5. Conclusion
Cambodiahas experiencedmore than two decadesof war aod intemal unrest
which destroyedtremendowly all superandinfrastructureofthe counfy. Sincethe war
has ended,the national economyof this country relies mainly on foreigd aids and
international and bilateral or multilateral assistances.
In addition to this, exports of
products
is
hard
agricultural
another source of
currercy eaming in which expo( of
crocodile skins and deriEtives may contributean importanl percentagein the fishery
sector.
Since after the 1993 llN sponsoredgeneraielection, this country has bee!
adheringwith the intemational community and hasparticipatedin many intemational
treaties and conventions such as the Earth Summit, the Convention on Biological
Divelsity (1995) and the Conventionon IntemationalTrade in EndangeredSpeciesof
wild Fauraand Flora (CITES) in 1997.Cambodiahasbeen a Pafiy to CITES for only
about9 monthsand assuch hasvery litde understandingofand no plactical experience
in implementingthe provision ofthe Convention.
The CITES Management Authodty of Cambodia requests the on-going
assistanceof the CITES Sedetariat and cooperationof interestedPartiesto enablethe
Govemment of Cambodia to develop the nec€ssary&derstanding, technical and
administrativecapacityto disohargeits obligationsasa Pdty to the convention.
Refererces
Abmed M. Tan4 T. S. a:rd Thuol N. 1996.Sustainingthe Gift ofthe Mekong.The
future ofcapturesfisheriesofCambodia.Watershe4People'sForum on
Ecologyin Bunna, Cambodia,Lao PD& ThailandandVietnam;vol. l. No. 3.
Bardacb J. 1959.Reportott Fisheriesin Cambodia.USON4/Cambodi4
PhnomPeoh,
Cambodia.
Departrnent
ofFishedes,1987.Fiat-lawno.33 of9 March,1987on Fisheries
N4anagemeft
and Administration.PhnomPenb,Cambodia.
DeparhnentofFisheries, 1998.Proclamationon Procedureto Kill, Skin andExport
FarmedCrocodilesno. 269 ofJune 19- 1998.PhnomPenh-Cambodia.
Jenkins,R W. G. 1998.CaptiveBreedingof Crocodylussiamensirin the Kingdom of
Cambodia.Proposalto registernoruinatedbrcedingoperatiorsinvolving
Crocodylussiamensis (unpublished).
Mni$ry ofEnvircnnent 1993.Royal Deqe€ oo. 126ofNovember l, 1993on
CreationandDesignationofProtected andMultipurposeUsesAreas.Phnom
PenlLCambodia
Ratanakom,P. 1992.Crocodile in Cambodia.Wildlife ResearchLaboratory;
Departmenlofzoology, Facultyof Sciencas,KasetsartUniversity,Bangkok,
Thailand.
SiamSociety,1992.CustomofCambodia.Secondedition,Bangkok,Thailand.
150
Thuok, N. 1993.The Potenlialofcrocodile Raisingin Rural Cambodia.Selfdirected
Studyfor the ftlfillment ofthe Master'sDegee ofRural Development
ManagementKhon KaenUnivenity, Khon KaeL Thailand.
Thuok, N ard Tan4 T. S. CrocodileConservationin CambodiaIn Proc€edingofthe
12thWorking Meetingofthe CrocodileSpecialistGroupofthe Species
Survival CommissionofIUCN - The World ConsewationUnion, Pattay4
Thailand,2 - 6 May 1994,vol. 1.
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154
EnvironmentalContaminantsas Concernsfor the Conservation
Biologyof Crocodilians
I. Irhr Bdsbin, JI., ChadesH. Jagoe,KarenF. GainesandJoanC. Gadboldi
SavanmhRiver EcologyI-abomtory
P.O. DrawerE
Aiken,SouthCarolina29802,U.s.A.
ABSTRACT: Historically, concemsfor the fate atrdeffectsof enviroDmental
contaminantshavenot beena high priority for thoseconcemedwith the conseflation
biology of crocodilians.Howeverstudiesof other groupsof vertebratessuggestthat this
is probablya mistake.With advancingunderstandingof factorsimpactingcrocodilian
canhave significant
populations,it is becomingincreasinglyobviousthat contaminaDts
impactsupotr a numberof thesespecies.Therc aretlEeeclassesof environmental
cotrtaminants:mdionuclides,heary metalsatrdorganics,includitrgthe estogen inhibitors.
Radionuclidesare generallythe leastimportantin terns of their overall impactupon
global crocodilianpopulations.They are of concemonly in certainlocalizedareassuchas
thosesurroundingDuclearindustrial facilities. Healy metalcontaminationhowever
occu$ woddwide, andis of concemto manytropical populationsof caimansand
qocodiles iDhabitingwetlandscontarlidatedwith mining effluents,particularlythose
associatedwith the extractionof gold andcopper.Mercury contaninationof alligato!
populationsin the southeastem
United Statesis widesFeadalld may,uDdelsome
consumption
of alligator meatby humansin this area.
conditions,limit the advisable
Concemfor the global impactsof anthropogenicestrogeninhibitors is of greatinterestin
environmentaltoxicology today,and studiesof the impactsof thesecontaminantsupon
the reproductionof Americana.lligators(AltiSator tuississi?iensis)wele amongthe first
to documetrtthe harmcausedby thesechemicalsuPonfieeliving wildlife.
This papersumrnarizesstudiesconcemingthe fate andeffectsof environrnental
contaminatrtsupon crocodilians. This surveyindicatesa genenl lack of
information rcgardirg the importanceof observedlevelsof contamimntsin both
individual animalsandpopulations. such infomation is essentialfor predicting
how contaminantsmay be limiting populationrcproductionor viability,
pafiiculady itr concertwith habitatdesfuction, over-harvestandotherIimiting
facto$. This surveyalsorevealsthe impoltanceof havinga thorcugh
undelstaodingof the basicecology,behaviorand natual history of the arimals
involved, with this beingparticularlyimportantfor predictingthe role that meat
from somecrocodilianscould play as a Potentialvectorof environmental
contaminationto the hurran food chain
155
INTRODUCTION
Worldwide effofis to prcmotethe coNervationandrecoveryof crccodilian populations
havehistorically focusedon the issuesof habitatloss andover-exploitatio[ Only
rccendy,now that someof thesespeciessuchasthe Ameican alligator haverecovered
stablenumbe$ anddemogaphics,hasit beenpossibleto evaluatethe possiblermpaqs,
that environmenralcontaminantsmay alsobe havinguponthesepopulations_This
situationis ilt sharycontrastto colservationconcemsfor other ver;brate predato$ such
asbftds.ofprcy. The tendencyof many environmentalcottaminantsto bi;magnify made
studiesin this areaa primary focusof early efforts to halt populationdeclinesof theseand
other avian species.Indeedconcemsaboutthe global impactsof althropogedc
chemicals,particuladyorganicpesticidessuchasDDT, werc at the foreiront of much of
toda]'s elvircnmental movement(Ca$otr 1962). Subsequentmanagementefforts based
on the barning or rcductionin the useof DDT andotherpesticidesrisulted in dramatic
recoveriesof many avianpredators.It thusbecameclearthat thesecontamina.D6
sometimessorvedasimportantlimiting facton for suchpopulations_ a lessonthat has
obviousimplicationsfor the conservationof crocodilianstoday.
As our unde6tandiDgof crocodilianecologyexpands,it hasbecomeclear that few if any
populationsof theseanimalsareimmunefrom contaminantexposurc.Even in the most
remotebabitats.crocodilians
maybe exposedro globallydistributedatmospheric
contaminatiol ilcluding radionuclidefallout, pesticides.pCBs or heary rnitals suchas
mercury.Additionally, crocodiliansliving nearpoint-sourcesof contaminantreleasesuch
asnuclearfacilities, midng operatiorNor areasofhigh agricultunl chemicaluseare
l.ikelyto showelevatedbody burdensof chemicalcortamination.What is notably lacking
however,is an unde$tandingof the impactsof thesecontaminantsuponthe individual
animals_and
their populations.The uniquephlsiology of qocodilians, which arelaigely
oikilotherms
but possessInally uniqueattributesof homeotherms,makesit Darticularly
tr
difficulr to predicltheimpaclswhicbconlamioants
mayhave.by simplyextrapolatiog
from toxicological studiesof corunon laboratoryspecies.
It is the pur?oseof this paperto describethe major forms of environmentalcontaminants
that may be of concemto crocodiliansandthet conservation.We summarizethe scarce
scientific literaturein this field (Table 1) andattemptto developsomebasicpriDciplesfor
uude$tandingthe impactsof environmentalcontaminantsuponcrccodilia:rsand how
theseimpactsmay be minimized. Finally, we suggestdbectioosfor fiJturercsearchand
indicatethe lreedto itrtegratethe resultsof suchresearchwith other studiesof qocodiliaq
biology, conservationaDdmanagement,
As indicatedin Table I , the publishedinformationconcemingenvironmental
contaminantsandtheir effectsupoDcrocodiliansis stronglybiasedtowardsthe American
alligatof (Alligator mississippiensis),Of the publicationslocatedon this subject,23138
(617a)concemthis one speciesalone,and 14/23(61Ea)of tle. wo d's crocodilian soecies
haveno publishedioformatiod at all in this regard. plainly considerableadditional
156
researchstill lemainsto be donein this are4 partiaula y for thosespeciesfound in the
Old World tropics.
CLASSES AND CIIARACTERISTICS OF
EI{I'IRONMENTAL CONTAMINANTS
Environmentalcontaminantsof impodanceto crocodiliansmay be groupedinto tlree
categories(1) organicchernicalsincluding the so-calledendocrinedi$uptors, (2) heary
metals,and (3) radionuclides. As will be shownbelow, substancesin all of these
categoriesmay sharecertaincharacteristicsin the ways in which they may be transported
in ecologicalsystemsby both biotic and abiotic (phlsical) mechanisms- thereby
becomingconcsrtratedto somedegreein tle bodiesoftop camivoressuchasthe
qocodilians. However,thesecategoies also differ from one arcther in someimpodant
ways andthus will be discussedseparately.
Organic chemicsl contaminsnts are orgaric carboncompounds.They are more sirnilar
to the body's biological moleculesthan are eitherheary metalsor ndionuclides. They
thereforehavea greatertendencyto becomaincorporatgd,often in inappropdateoi
harmfirl ways,into naturalbody ptocesses.For example,olganic contarninantsthat act as
endocrinedi$uptols may mimic the actioru ofhormones andother regulato$ ofthe rates
ofiDtenal physiologicalprocesses.Thesedi$uptive actionsare often
and sequences
most notablewhen they occur during embryonicor other developmertalstageswhele
efects may linger long after the cornpoundshavebeeneliminatedAom body.
OrganochlorinechemicalssuchasDDT andits metabolites,particularly a.ffectingtop
camivoressuchasbids ofprey, wete amongthe first subslanc€sto be identified as
etrvironmentalcontaminantsimpactingthe naturalworld asa result of humanaclivities.
This in tum produceda profoundchangein the genemllevel of societalawarenessand
concemfor environmentalissues(Carson1962). Later,the Americanalligator became
one of the first fre€-living wildlife speciesfor which field and laboratorystudies
documentedthe effecGof organicchemicalsacting asendocrinedisruPtorsuponthe
embryonicdevelopmentand hormonalcontrol ofthe reproductivesystem(Guillette and
Crain 1998). As indicatedby the casesofthe birds ofprey and alligatorsoited above,
someorganicchernicalsarc highly resistantto enviroDmentaldegre&tion. They thus
may peNist for long periodsof time during which they or their metabolitestend to
becomebiomagnifiedat higher levels ofthe food chaioThe useof someofthe most notoriousorgadc contaminantssuchasDDT and
polychlorinatedbiphenyls(PCB's) hasbeenbarned in many countriesincluding the
United States.Al&ough thesechemicalswereproducedandrelea$edinto the
anvircnmentin significant quantitiesprior to the 1970s,the harmftrl residuesaod
metabolitesofthese substancesstill persistin eventhe most rcmotepars ofthe biosphere
today. Moreoversomeofthese subslancesare still being usedwidely in somecountries'
Thus despitean early focus ofboth scientific researchandpublic concemaboutthese l5'7
contaminantsandtheir effects,crocodilianpopu.lationsin many parts ofthe world are still
-found
l'ulnerableto their impacts. For example, Delany etal., (l9gg')
that detectable
levelsofDDT, DDD, DDE, dieldri4 heptachlorepoxide,lindaneand pCB,s persistedin
the tail muscleof Florida alligatoN in I 9g5, over a decadeafter the useof someof those
substances
was bannedin that state. Heinz et al. O99l) also found organocblorine
pesticidesand PCB's in the eggsofalligators from sevenl Florida lakls in 19g4ard
1985.DDT metabolitesand heptaEhlorepoxidewere alsofound in the eggsof Morelet,s
crocodiles(Crocodylusmoreletii) j\ all tfueehabitatssurveyedby Rainwateret al. (1997)
in Belize. Io this latler studyall eggswere collectedftom lagoonsassociatedwrth areas
of agicdtural development- suggestingthat useofpesticides or herbicideslllay have
beena factor in the releaseand subsequentaccumulationofthese contaminantsin tle
qocodile populationsofthe area.
Eeary ntetql contamizazrr are globally distsibutedasa result of releasesfrom a vanety
'lhese
of sourc€s.
include mining and smeltingoperations,industrial efiluents,paper
prodlction,
Eflincineration, agdcu.ln[aldrainwaterandelectric power generationusing
fossil fuels (Wotfe et al, 1998). Ofparticuiar importaaceto crocoiiliaru il tropical
riverhe systemsarepoint souces of healy metalsfroe areasof mining and extraction.
Brazaitiset al. (1996)discussthe potentialfot the exposureof caimanpopulationsto
-olllu"49l
aosociatedwith gold mining in the New Wortd tropics. Bakowa
Tllj
(1996)and Figa (1996)describercsearchassociatedwith conoemsfor the potential of
cappermining efluents entelingthe Fly River systemof papuaNew Guinia to elevate
the healy metal contaminantexposureof aquaticbiota inhabitlng this watershed.
Montague(1983) andKula and Solrnu(1996)indicatethat this river systen includes
someofthe most import nt habitatfor crocodilepopulationsin this part of the world.
The heavymetal of greatestconcemto crocodiliansis mercury. Mercury entersaquatrc
food chainsas methylrnercurywhich is ptoducedby microorganismsu"tiog opon
inorganicmercurjraccu&ulatedin sedimentjand soils (JacksonlgSg; Woi-fe;t al. 199g).
For rcasonsthat are often not clear,methylmercuryis particularly elevatedin certain
geographicarcassuchasthe Evergladesregionof southemFlorida (Ogdenet al. 1974;
Facemireet al. 1995). In this region,studiesof mercuryin a.lligatorsGve producedone
ofthe most exteDsivedatabasesfor any singlefom of environmentalcontaminantin a
crocodilian( Delany et al. 1988;Hord et al. 1990;HeiDzet al. l99li Heaton_Jones
et al.
1997;Yanocbkoet al. 1997;Jagoeet al. 1998).
Someheaty metal contaminants,particularlymercury,areknown to biomagni!, anclthe
highesttissueconcertations ale found in the highesl tophic levels of food;hains (Eisler
1987;_Wolfe€tal. 1998). As a consequenc€
ofits pattemofcontinuing bioaccunulation
over the lifetimeof eventhe longestlived orgaldsms,the highestlevels of mercury
contaminationof crocodiliansarc invariably formd in the oldestaad largesrindividuals in
the_populationCYanochkoet al. 1997;Jagoeet al. 1998). A combinationoflong life span
andhigh tophic position thus combineto makecrocodilianspeciesone ofthe mosr
sensitive'lvorst possiblecase"indicatorsofhealy metalcontaminationin aquatrc
systemstbrcughoutthe wodd. Bnzaitis et al. (1996) describethe conuminaion oftwo
158
speciesof SouthAmedcall caimanpopulationsandtheir iiveine habitatsdowlstream
from gold-minitrgopemtionsin Bmzil (Table 1). The releaseofmercury into these
habitatsis the result of amalgamextractiol of gold-bearingores,with contaminatedwaste
discardedback into the wate$hed. Mercurycontaminationhasbeenreportedby Mdm et
al. (1990)asmuch as200 km downsteamfrom the nearestsuchgold-minitrgoperation.
Rqdiooctivecontamin4nts area subsetof metal contaminants,They are genemllynot
encountercdin crocodiliar populatiorsat levelsthat would makethem a causefo!
coocem.To be sue, globa.lradioactivefallout from earlieratmospherictestingof nuclear
weapoN and accidentssuchasChomobylin the fomer SovietUnion haveproduced
tracesignaturesof thesecontaminantsthat still persistin biota throughoutthe wodd today
(Bdsbin1991;1993).Howeverthechiefimportance
for
of thesecontaminants
crocodilianpopulationshasbeento se e asi4 qilg tracersof ecologicalstructue and
function in the systemsin which they arefound. For example,the longJived gammaemifting radioisotopecesium-137hasbeenusedto showthat Amedcanalligatorshave
one of the slowestIatesof contaminantaccumulationandtumovereverdocumentedfor
a.oyl.iving organism(Brisbin et al. 1996). Studieswith this sameisotopehavealso shown
that io an equitibrium statein a contaminatedrcservoir,fteeliving alligator populations
incorporatewithin their biomassonly a minuteamoudt(lessthan 0,002 70)of the total
inventoryof this contaminant.Ir contrast,over 99 % of this contaminantis found in the
sedimentsand wate! column,with ooly 0.4 7oin all of the reservoir'saoimal species
combined(Brisbin 1989). Thesesamestudiesalsoshowedthat the alligatorsdid not
biomagnifycesium-l37 abovethoselevelsfound in their pley, in contast to someothel
metalssuchas mercury. They alsodid not showa tendencyto accumulatehigherlevels
ofcesium-I37 contaminationwith increasingageandsize. ln this seDsetheir cesium-I37
contaminationpattemwas similar to that shownby yellow bullheadcatfish(Ameiurus
,ataris) hhabiring this sameleseryoir.
Radioactivecontaminantsare generallyan environrnentalconcemonly wherctheir levels
havebeenincreasedby nuclearweaponstests,nuclearindustdal accidentsor spills. Most
all suchsitesare in the temperatezotreof the oorthemhemisPhereandthe only one
known to involve a crocodilianhasbeenthe Urited StatesDepartmentof E[ergy's
SavannahRiver Site (SRS)in SouthCarolina,USA. The Americanalligaton residelt on
the SRShavebeenstudiedexteNively for over 25 years(Murphy 1981;Brandt 1989;
Brisbitr et al. 1992;1996), Irng-term studiesofthe basicecology,populationbiology,
movementand behaviorandofthese alligatorshaveservedasthe basisfor the analysis
andinterpretationof the fate andeffectsof radioactivecontaminaltsin thesesame
animals@risbin 1989;Whicker et al. 1990;Brisbin et al. 1992',1996)- Thesestudies
havegenerallyconfirmedtiat the elevatedlevelsof cesium-137fouDdin thesealligato$
havehadno detectablenegativeeffectsupontheir healthor populatioovigor. However,
aswill be discussedlater, underceftainconditions,someindividual alligatorscan
accumulatemuscletissuelevelsof cesium-137that would makehurnanconsumptionof
their meatan issueof potentialconcem.
159
CROCODILIANS AS INDICATORS
OF ENI'IRONMENTAL CONTAMINATION
Contaminantssuchas organicchemicalsor someheary metalswhich biomagift through
the food chain showtheir highestlevels in the tissuesofthe top predatoN. In suchcases
th€seanimalsmay be usedas sensitiveindicatorsofthese contaninants,occurence in
otherpads ofthe environment. This principle resultedin the eggshellthinning ofbirds of
pley becomingone ofthe impo ant early waming sigDsofenvironmertal contamination
with DDT atd other pesticides(Carson1962;Andersonand Hickey 1972). Long-lived
predatorsrnaybe especiallyimportantin this regardsinc€their aontaninantburderucan
rcpreseDtintegratedassessments
oftbe enviroDmentalavailability ofcontaminan* such
aspesticidesor healy melals over extendedpedodsoftime. As longJived top camivores
in all ofthe habitatsin which theyoccur, adult crocodiliansare also likely to show any
efects ofsuch contaminants.Indeeddatafor Amelj.c,analligato:rs(Altigatol
nississippiercis) litring in Iake Apopk4 Florida were amongthe first to demonstratethe
impactsof estrogeninhibitors uponthe reproductionofa free-living wildlife population
(Grosset al. 1994;Guillette andClain 1996;cuilette et al. 1996;cuiuetle et al. 1997).
In this caseabnormallylow alligator clutch viability (Woodwardet al. 1993)wasthe fust
earlywaming sign ofcontaminant impact andresultedin the alligatot servingasan
important"sentinel species"in this regard.
Despitethe abovecoDsiderationssuggestingthe appropdateness
ofadult crocodiliansas
indicato$ of levels ofenvitonmental contamination,a deg.eeof cautionmust be
incorporatedinto any efort to usetheseFnimalsin this way. Someofthe basic
considemtionsinvolved in selectingany individual speciesor groupof speciesasan
indicatorof environmenlalcontaminationlevelshave beensuiDmadzied
elsewhere
(Brisbin 1993). As indicatedin that study,one ofthe most importantofthese
coEiderationsis to determinewhethercontaminationlevels in the proposedspeciesor
speciesgoup actually correlateswith contaminantlevels itr other comDonentsofthe
ecosystemwhich it iohabits. Although this hasbeendooefor somespeciesof vegetaron,
invertebratesand fish (e.g.Aadersonet al. 1973)suchinforrnationhasneverbeen
collectedfor any speciesof crocodilianand canonly bg assumed.
Finally, the value ofatry speciesasan indicator ofenvironmental contaninatioo depends
in largemeasureon the amountof basicbiological infonnation andnaturalhistory, which
is availablefor it. Nowherc is this truer for examplethan in the caseofinfomration on
migratio4 movementsandhomerangebehavior,aspointed-outfor exanple by Brisbin
(1993)in the selectionaudinteryretalionofdata fiom bids as indicato$ of
enviroomentalcontamination. lvhile not asmobile asbfuds,adult crocodilianssuchas
Americanalligators can and do ftequendymove over extendeddistances(e.g. Brisbin et
al, 1996). Howeveruder other conditionsin othq habitatsadult alligatorsmay also
occupyrclatively small "activity ranges"(Goodwin andMarion I 979), and in fact
Delanyet al. (1988) cite this characteristicasone of tle featureswhich they feel make
alligatorsappropriate"indicators of local envitonmentalpollution". Guilletle and Crain
(1996)provide evidenceofthe value ofalligators asindicatoN oflocalized contaminanl
uptakeandeffects. They showedthat the impactsofendocrine-di$uptof chemicalsupon
the extemalgenetaliaof alligatorsfound in the irDmediatevicirity of tle site ofa toxic
wastespill were more pronouncedthan in otherregionsofthe sameFlorida lake. Plaidy,
movementdata,suchasthat which may be collectedthroughthe useofradiotelemetry
equipment,must be consideredbeforethe full meaningof any given contaminantlevel
canbe properlyintelpretedin any given situation,when dealingwith aoimalsas
potentiallymobile asadult alligators.
EFFECTS OF EIWIRONMENTAL
CONTAMINANTS ON CROCODILIANS
concems,the importanceof understandingthe
Fromthe point of view of conserva.tion
uptzkeandcoDcentratiooof envircnmentalcontaminantsby crocodiliansrelatesto dre
effectsthat thesesubstancesmay have on the individuals in which they may accumulate
Although sucheffec* areusually consideredto be ditectly Foportional to the level ofthe
contaminantobservedin the individual's body, suchan interpretationis not always
staightforward. Co$ideration must also be given for exampleto the amout oftime that
the individual hasbeenexposedto the observedlevel of contamination.An older adult
crocodilewhoseliver hasbeenexposedto a mercuryburdenof 0.5 ppm mercuryfor the
past 15 yea$ fo! example,may havesufGrcdmore ill efects ftom this contaminantth'n
a youngeranimal which had only recentlyanived in a more contaminatedhabitat and
accumulateda burdenof 0.9 ppm mercuryover a period of only severalweeks Here
again,a thoroughknowledgeofthe basicecology,behaviorandnaturalhistory ofthe
animalsin questionis essential.
With the abovein mind, tie publishedworld literatue offeN scantevidercethat
environmentalcontaminantshaveeverexerteda significantimpactupon any crocodilian
populationsin terms ofcausing dircct mortality. As will be discussedin more detail
below,what uequivocal evidencethere is for conta$inanteffectsupon thesereptiles
underfield conditionsall involvesreproductiveimpairmen! andthat mainly being the
iesult ofexposureto endocrine-disruptiveorganicchemicals. Moreover,beyondthe level
of impactsupon individual orgaaisms,thereis vfnrally no infomration conceming
populationJeveleffectsof environmentalcontaminantsupon crocodilians.
The threemajor classesof environmentalcontaminantsvary widely in the dege€ to
which they havebeenimplicatedascausativeagentsproducingefects upon crocodilians'
Thereis for example,no evidenceof any effectswhatsoeverasthe rcsult ofndionuclide
contaminantsaccumulatedby Americanalligato$ - the only specieswhich hasbeen
studiedin this regad @dsbin 1989;Brisbin et al. 1992;Brisbin et al. 1996). Heary
metalshowever,particularly mercury,havebeenimplicatedashaving possiblynegative
impactsupon crocodiliansin severalpars ofthe world. In light ofthe abovecaveats
concemingthe needfor carein iDferringcootaminantefects without thorough
informationon the alrimals' basicecologyandnaturalhistory however,someofthese
irnplicationsof contaminanteffectsmust be viewed with caution. News media for
l6l
example,being awarcofthe elevatedlevels ofmercury found in alligatorsfrorll the
Evergladesregion of southFlorid4 have describedthe poor body condition ofthese
animalsasbeing a condition in which, .Mercury pollution may also be involved."
@arr
1997).
Brazaitiset al. (1996) similarly suggesttlnt mercuryand leadconlaminationresultms
from gold mining activities in Brazil may be negativelyimpacting caimanpopulationi
living downsteam from theseoperations.Theseautho$ admit thal, ,.Theprecisesource
oflead contaminationin caimanirr Brazilian gold-mining regionsis asyet unkno\4n. . .,,
andthat "The short- and long-tenn effectsofmercury and leadcontaminationand
toxicosis on crocodilianpopulationsis yet uDlnown." Howeverthey then go_onto
suggestthal "it is rcasonableto assumethat a seriousthreatexiststo thosespecies,well_
beingaodtothecontinuedviabilityofpopulations,....'Whilethismayweilbethe
case,no mercuq/contaminationlevelsw€re evendetemined for thesecaiman,being only
availablefor their pley and the sedimentsoftheir rivedne habitats. Under such
conditionsthe conclusionthat thesecontaminantsdo indeedposea.,seriousthreat,
would be difEault to substantiate.
Subsequendy,
Bmzaitis et al. (1998)refer to this samesituationand descdbecaimanas
being found "dying ofpollution . . ." in theseareas. This studyagainconfirms that
mercurycontaminationlevels argknown oDlyfor the habitatsandnot for the animat5
themselvesandthat aboveall, 'the efect of mercuryand leadon caimansis not known',.
They also suggestthat 'bne canonly presumethat the metalsare asdetrimentalto thes€
cytulT asto-h]!nans". That this is a poor presumptionis shownby Wolfe et al. (1998).
This review of the scantlitetatue availablefor the effectsofmercury on reptilesrcported
no effectsof tofcity in snakesfed diets containingup to two orde$ ofmagnituae higher
levelsofmercury contaminationthan thosewhich causebebaviomland,/orreuoductive
impaiment in birds andmammels. CoDtr.olledtoxicological studiesare thusneeded
beforethe levels ofmercury andothermetalsvrhich causeharm to crocodilians,canbe
determi&d with certainty. Until suchiaformation is availablehorrever cautionmust be
usedin athibuting deathor debilitationobservedin given individuals.
In January1996a very large (total length 3.92m) adult male alligator was found deadof
unknowncausesin the Par Pondreservoirof the SavaanahRiver Site. Subseouefi
analysesoftissues fiom this alligatorrcvealedwet-massmercurylevelsof 3.4-gppm
muscle,33.55ppm kidney, and 158.85ppm liver. Theseexh"aordinarilyhigh levels of
mercuryconlamillation,particularlythat in the liver, arethe highesteverreportedin the
literaturefor any form of freeJiving wildlife. They evenexceedthoseleveis known to be
associatedwith lethality in controlledlaboratorystudiesofmercury dosageofa wide
variety ofbird, marnmal,reptile andamphibianspecies(Hall l9g0; Wolfe et al. l99g).
Under theseconditionsit would not be uffeasonableto suggestthe involvementof
melcury contaminationin the deathofthis alligator. This conclusionis further supported
by this alligator's generallyemapiatedcondition at the time of deatlqsuggestinga geneml
weakeningofthe animal during what must havebeena long-termchrcnic exposureto
this pollutant. In fac! this samealligator had beencaptuledand markedover 20 years
162
earlierin the samereservoirin which it subsequentlydied. For at leasttwo ofthose yea$
it carrieda radiotransmittercorirming its continuedresidencein the reservoi which is
lno\xn to showelevatedlevels of mercurycontaminationin both sedimentsandvarious
foms ofalligalor prey @dsbin et al. 1996;Yanochkoet al. 1997). Thesefactsfiuther
strengthenthe possibility that the deathof this particularalligator may be the first
documentedcaseof mortalig of anyindividual qocodilian likely io be the result of
exposurc. It is difficult to understandhowever,why many
environmentalcontaarin€mt
other alligatorchaveilhabited this samercservoirfor tleir entire lives without showing
any apparentill effectsfrom contaminantexposue @dsbin et al. 1992; 1996). Neither
haveany other alligatorsstudiedin this reservoirshowedsuchextemely elevatedlevels
althoughmost ofthe oneswhich have beenstudiedhave
oftissue mercurycontamiDatioD,
presumably
were not as old asthe alligator which died
not beenaslarge andthus
CYanochkoet al. 1997;Jagoeet al. 1998).
contaminantson fteeThe clearestcaseyet documentedfor the effectsof enviroDmeDtal
on
living crocodiliars hasbeenthe impactsoforganic contaminants the rcproductionof
a.lligatorsin Irke Apopka Flodda USA. Field and laboratorystudiesof the reproductive
impairmentofthe alligatorsof Lake Apopka will be describedfiuther in other papersin
thii volume. Briefly howeverit is importatrtto point-outthat the pollutantsinvolve4
which were largely pesticidesfiom srmoundingagriculturaloperatiors, effluentsftom a
nearbymunicipal sewageteatuent facility andcontaminantsfiom a major industrial
pesticid€spill (Grosset al. 1994), were largelyendocrinedisruptorswhich exerttheir
geatest inJlueDceduring embryonicdevelopmentaftei havingbeenincorporatedinto the
igg (Crain et al. 1998). Heinz et al. (1991)studiedthis situationand concludeddlat, "it
did not appearthat anyofthe pesticideswe measued [organochlorines]werercsponsible
for the reducedhatchingsuccessof Lake Apopka eggs." Neveltheless,currenttbinking
basedon a numbe!ofyea$ ofboth field andlaboratoryresearchbave still concludedthat
endocrine-disrupto!chemicals,possiblyinvolving synergismsbetweenpesticidesand
othercontaminantssuchasPCB's, havebeenresponsiblefol the observedimpactson
alligator reproduction(Grosset al. I 994; Guilette and Crain I 996).
The expressionsofthese impactsupon lake Apopka alligatorshavebeendocumentedin a
varietfof forms. They include alterationof gonadalmorphologyandplasmasex stercid
andhomronelevels (Guilletle et al. 1994i andGuillette et al. 1997,respectively),
alterationofgonadal steroidogercsis(Guillette et al. 1995),and alterationio the size and
degreeofdevelopmentof male extemalgenetalia(Guiuetteet al. 1996). Effectsofsuch
reproduaive impairmentof individuals hasalsobeenexprcssedat the populationlevel as
declinesin alligator populationdensitiesandshifts in populationagestuature
(Woodwatdet al. 1993). Subsequentto their documentationin the lake Apopka
alligators,simila! effeatsofendocrine-di$uptor chemicalshavebeenfound in other
reptilessuchasturttes(Guillette and Cmin 1996),and concemhasgrown globally for the
possibility of similar impactsoccuring in a variety of ve ebratespeciesincluding rnan'
t63
Crocodilians as Potential Vecton of Contaminants
To the Human Food Chain
Although thereis a clea.rneedfor bettetinfomation on the effectsofvarious
contamtEnts on qocodilians and otherreptiles,thereis sufficient datanow to predict
dsks to humansthal consumecrocodilianmeatftom contaminatedenvironments.
Mercur-y,particularly in tle methylatedfomr that accumulatesin fish and wildlife, is
toxic to humans,with pregnantwomenaod yormgchildrenbeing at particular dsk
becauseofpotetrtial developmentalefects. We estimatedtlrc amountof alligator mear
that a regular consumercould safely€atper week(Table 2). basedon publishiedmercury
concentrationsin alligator muscleandrefetencedoses(Rfl,s) for ingestionof
methylncrcury, aspublishedby the Wortd Health Organizationof the U.N. andthe U.S.
EnvironmentalProtectionAgency (WHO 1990;EpA 1997). The WHO advisesthat 0.47
pg Hg per kg ofbody nass per daycould be safelyconsumedover a lifetime. The U.S.
EPA hasadopteda more stict standardof 0.1 Fg Hg per kg body massper day. Thereis
still debateover the relalive medts ofthese standards(Egelandard Middaugh 1997),so
we calculatedconsumptionlimits basedon both standardsfot comparison. The
calculationsfot maximum amouts that could be cousumedper weekassume(l) an adult
bod-y.mass
of70 k9, (2) rhat all mercuryin the alligator meatis methylnercury, (3) that
10070ofthe ingestedmettrylnercury is absorbed(\VHO 1990),and (4) that therc are tro
additional sourcesofmethylmercury in the diet. Ifthe latter assumptionis not tue, then
only lower amountsof alligator meatcould be safelyconsumed.Likewise, ifthe body
massof an individual werc lessthan 70 kg, a proportionally lower amout ofmeat would
be consideredsafe.
While many ofthe abovecalculationsare basedon averagevalues,it is important to
recognizethat individual animalsin somelocationscansometimeshavemuch higher
mgrcuryconcentations,and thus it would be safeto eat far lessmeatfiom such
individuals. For example,a large alligator foud deadia par pond on the SRSin 1996
hadabout3.5 mg Hgikg wet massin its muscle;by the WHO standard,it would be safe
to corNumeonly 54 g per week of this meat,while the more conservativeEpA standad
wglld
4low consumptionofonly l4 g per weekofmeat at this coqcenhatiou.Also,
while the organsof alligatorsare seldomconsumed,they usually containfar higher
mercuryconcentutiois than muscle(I{eaton Joneset al. 1997;yanochko et af,.1997;
Jagoeet al. 1998), The liver ofthe alligator found deadin par pond in 1996contained
159mg Hglkg wet mass;it would be saf€to consrunea mere 1.3 g per week ofliver at
this concentrationusirg the ltr/Ho RfD value, andlessthan 1 g by the EpA standard.
Radiocesiumin the diet ofhumans leadsto inoeasedrisk ofcancer. This contamirunt
may be of potentialconcemto hrunansconsumingcrocodiliansfiom areaswith histories
ofradioactive contamination,suchasthe SRSin SouthCarolin4 USA. Although the
SRSis closedto public accessandthereis no alligator hunting, laxgeralligators have
beenshownto be capableofleaving the site'sboundariesandmoving onto pulblic lancls
wherethey could be harvestedasnuisanceanimalsandtheir meatmarketedfot humaa
I6{
consumption(Brisbin et al. 1992;1996). To estimatethe risk associatedwith consuming
alligatorsfiom the SRS,we convertedradiocesiumconcentrationsin muscleasreported
by Brisbin (1989) andBrisbin et al. (1996)to committeddoseequivalents,using a value
of 1,35x 10{ pSv/Bq ofingested radiocesium,asrecendypublishedby Suo et al. (1997).
The IntemationalCommissionon RadiologicalProtectionrecommendsthat the total dose
fiom ingestedradionuclidesto the geneBl public shouldnot exceed1 mSv per year
flCRP 1990). Assumingno additional sourcesof radionuclidesto the diet, we calculated
ftom various SRSlocations(Table
the amountof alligator meatttEt could be aoDsumed
3). This table also includesdatafor a.rlalligator removedfrom a higbly-contaminated
seepagebasinat the SRSin late spring 1998. By ICRP standards,it would be safeto
consumelesstha! 4 kg of neat with this radiocesiumconcentrationover the courseofa
year. In contrasl radiocesiumlevels in most alligatorssampledat the SRSweremuch
iower, andgoportionally higher amountsof meatcould be safelyconsumed.
Finally, it is impoltant to rcalize tbat the individuals most likely to consumelarger
amountsofmeat fiom crocodilianssuchastle alligatorsdescribedabove,would include
subsistencehuntersandfishermenwho would be likely to also take-in elevatedlevels of
the samecontaminantstom otherportions oftheir diet aswell (JenkinsandFendley
1968). Estimationsofthe overall contaminantrisks to hurnansconsumingmeatfrom
crocodiliansthus needto considersociologicaland demographicfactorsfor the target
consumerpopulation(s)aswell asthe levelsof contaminationin th€ animalsbeing
harvestedfor consumption.
ACKNOWLEDGEMENTS
The preparationofthis manuscriptwas supportedby fimncial assistanceawardnumber
betweenttre United StatesDepaftirent ofEnel$/ andthe
DE-FC09-96-SR18546
University ofGeorgia's SavannahRiver Ecolory Laboratory. W. Stephens,P. Consolie,
aodP. Jobnsassistedwith field shrdies. We axeparticularlygratefulto P. Rossfor
and adviceand for helpingto focusthe atlentionofthe Crocodile
encouragement
SpecialistGroupupou aontaminantconcarnsin global populationsof crocodilians'
165
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.
Heaton-Jones,
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r68
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Peters,L. J. 1983.Mercury accumulationin the Americanalligator. M.S. Thesis.
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170
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160.
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Union- Glaod. Switzerlaod.
1?r
Table 1. Surveyofthe rvorld literaturedescribingthe fate and/or effectsofenvironmental
contamrnantsin crocodilians.
Species
Location
Contaminant
Reference
IIigator mississippi ensis Florida (USA)
Merclq'
nonda(UsA)
Metals & Organics
Florida (USA)
Orgadcs
Ceorsia(USA)
SouthCarolina(USA)
Mercury
Mercury
soudcaroliM
l Radiocesium
I
Souti Carolina& nodda I Mercury
(usA)
A igaror sinensb
Brazil
Ftorida(usA)
Florida
rusA)
II
Metals & Orgadcs
I Mercury & Irad
I
|
Organics
Metals
I
Crocodylxsmoreletii
Crocodylusniloticu,
Mercury & Organics
I Merals& Orgarics
OrgaDics
I
ziDbabwe
Crocodylusrhonbifer
Tonistona schLeglii
|
SouthCaroliDa,
Florida,& | Mercury
GeorEiaruSA)
I
r,ousiam1USrl
I Zitc
China
I Organics
Bnzil
I Mercury & Lead
z:l
I
Lead
Lead
112
Heaton-Joneset al. (1994)
Heaton-Joneset al. (1997)
Hold et al. (1990)
Peras(1983)
Delaiy €t al. (1988)
Heinzet al. (1991)
Crainet al. (1998)
Grosset al. (1994)
Guillette & Crain (1996)
Guilette er at (1994)
Guiltetreet al (1995)
Guillene et at (1996)
Guil€tte€t al(1997)
woodwardet al. (1993)
Ruckel (1993)
Bowles(1996)
Rhodes(1997)
Brisbin et al. (1996)
Bdsbin (1989)
Brisbinet al. (1996)
Yanocbto et al. (1997)
Jagoeet al. (1998)
Lanceet al. (1995)
Zi-miog et al. (h Fess)
Brdzaitiset al (1996)
|
Bn"iitis et al (1998)
|
Vermee!et aL (1974)
|
BrEz.aitiset al (1996)
I
Brazaitiset al(1998)
|
Ha[ etal.(1979)
|
ogdenet al. (1973)
|
StoDebumer& Kushlan I
(1984)
I
Raitr$"tereral (1997) |
Phelpset al. (1986)
|
Bilhs and Phebs ( 1972) |
rtsessels
€t al. (1980)
I
cook et al. (1983)
|
cook €,tal. (1983)
|
Table 2. Mercury concentrationsin alligator meatin the southeastemUni&d States,aIId
calculatedweekly coNumption linits basedon World Health Organization(WHO) atrdU.S.
EnvirctunentalProtectionAgelcy (EPA) referencedosesfor mercury in food.
Totd Mercury (mglkg
SaDrpliogIncatioD
EvergEoes.i ronoa
Cental Floridan
Okefenokee,Georgiau
SRS,SouthCarolina'
Florida'
w€t mass)
Rarge
Mean
1.30
0.43
0.19
1.08
0.61
0.39-2.92
0 . 1- 1 . 4
Florida"
Georgiad
f tonoa
hvefglades,
2.4
Adourtt that could be safely
consumedperweekotr a rcguler
basisGrams)
WEO standard
EPA standard
150
465
1053
185
38
4
258
45
327
68- 5t2
142- 2000
80
t7 - 125
35- 490
7l
18
d dataAom Ruckel(1993)
e darafrom lteaton-Joneset al. (1997)
a darafrom Jagoeet al. (1998)
DdataAon Delanyet al. (1988)
c dataAon Hord et al. (1990)
Table 3. Muscle radiocesiumin alligatorsfiom the SavannahRiver Site, SouthCadin4 USA,
with calculateddoseequivalentsto potentialhumancolsumers,and maxilnum amountsihat
could be consumedaccordingto guidelinesfrom the IntemationalCo[u[ission on Radiological
on a wet massbasis.
Protecrion.All valuesexpressed
Committed
dose
equivalent
Marimum copsumDtion
Muscle
peryelr
per week
if
ingested
radioc€sium
Locrtion
on
the
Sadpling
l)
(msv
(Bq
kss1)
Sav&nn.h RiYfi Site
1l
20.2'
0.21
F Area SeepageBasin
ParPondmean,pre{lawdol,n
Par Poudmean,post-dnwdoivn
Highestvalue recorded,Par Pond
Irwest value recorde4 Par Pond
PondB (whole body count)
0.48
0.3'7
0.63
0.24
0.49
dataAon Brisbin (1989); Brisbin et al. (1996).
P, Fleddeman Ders,comm.
173
0.0065
0.0050
153.8
200.0
2958
0.0085
0.0038
0.0066
17.6
263.2
2261
l) l.)
29t3
3896
5061
CONSEQIIENCESOF HORMONE DISRT]PTIONOF SEXUAL DE\tsLOPMENT FOR
CROCODILIAN CONSERVATION
David Crews I and JamesperranRoss2
IDepartment
ofZoolory
University ofTexas at Austin
Austin,Texas78712USA
2Crocodile
Specialist
Group
FloridaMuseumofNatural History
Box I17800
UniversityofFlorida
Gainesville.
Florida32601 USA
ABSTRACT
All crocodilians exhibit temperature-dependent
sex determination,in which the incubation
temperatureofthe egg dudng the middlethird ofdevelopment,not sex-specificchromosomesat
f€rtilizatioq determinesthe iodividual'sgender. Researchsuggeststhat steroid hormoneshave
the sameefect as incubationternperaturgdirectingse)(determinationin these species. Todat's
environmentcontains a number of s]'nthetic compoundsthat mimic or block the actions of
steroid hormones,known genericallyas endocrinedisruptors. Thesecompoundsare found in
pestiaides,herbicides,fertilizers and plastic stabilizers. They pe$ist in the environmentand as
they pass up the food-chairg they are magnified and concentlatedin lipids in animals. In
crocodiliansthey accumulatein the yolk and disrupt normal seFral developmentin the embryo,
resldtingin abnomal gonadsand morphologyin the resultinghatchling. Thesecompoundscan
alsohaveadvene effectson other aspectsof the phenotlpe includinggol}th and behavior. The
utility of thesecompoundsin industryis suchthat they will continueto be used. Thus, a basic
knowledgeof how steroid hormonesare normallyinvolved in the processof sex determination
anddiferentiaiion is necessaryifwe are to understandhow thesee;docrine disruptingchemicals
exerttheir actionsand enableus to developmethodsto protectthe embryo.
INTRODUCTION
The suggestionthat certainchemicalscanmimic the action of estrogen,profoundly afecting the
cou6e of sex-ualdevelopment,emergedfrom studiesof alligators, birds, fis[ and turtles in
natule. These chemicalsinclude herbicides,insecticides,fungicides,styreles, polychlorinated
biphenyls, and penta- to lonyiphenols and have been shown to disrupt nomal endocdne
functions. This leads to aberrant developmentof female and male repioductive tissues and
resultsi'l decreasedfertility or sterility. Theseeffectsare consistenrwirh alterationsone might
articipate ifthe steroidhormonedependentprocessesthat regulatethesesystemswere impai;d
(Tablel).
I74
Table l. Characteristicsof endocrinedisruptingchemicals
iGIqr,'rrous
*
IN TllE ENvIRoNMENT
ANDPERSIsT
BUI
STRUCTLIRALLYDISSIMILAR TO THE STEROIDHORMONE MOLECULE
BIND TO STEROID HORMONE RECEPTORS
srERoID
eCigy strultlerrNc THEAcrIoN oF NATTIRALLY-ocCrJRRING
HORMONE-MEDiATED
NORMALSTEROID
ONELOCKING
rTORI'IOI.AS
DE\ELOPMENTAL EVENTS
ACCUMTJLATEIN YOLK
ACT DIIRING EARLY DEWLOPMENT
AND
ourcoME INFLUENCING MORPHOLOGY (2'SEX CTTARACTERS
oprewo
ENZYMEACTIVITYAND
cnowrrl, prrvslor-ocY (STEROIDOGEMC
BErIA'IoR
diiNisriiffm srrnon nonNtoxrr-s\Et-s),ANDPRoBABLY
r\?IcALLYFoIINDINNATIRE
rrrecrivn er q-ow)DosAGEs
NON-LINEAR DOSE-RESPONSECUR!'E
GREATERTHAN
0 pnrsgrlr iN I'rrrURES AND MAY SYNERGIZE PRODUCING
ADDITIVE EFFECTS
BE A
E)PERIMENTS WITH ESTRADIOL TNDICATETHERE MAY NOT
THRESHOLD DOSE
,l demonstratedio Americaoalligator
o demonsFatedin red-earedsliderturtle
ofsex deteminatiol
In this paperwe will rwiew bdefly the presentstateof-our knowledge
TSD specifically We wil
io,"n-"tr"t"', i'n generaland in crocodilans'andother reptileswith
inlluencenot only the t]?e of gonad
Doifltout that the hormonespresentearlyin development
sexstru*uresaswell as the growthand
of secondary
f;; il ;.o the d.rifferentiarion
ih";ll
of how
and adult. We will end by consideing somer€centdiscoveries
i"Lti"t oi,ft"j"t".ile
that are of
air-pto.. may influence these processesand consider some issues
"nJocri""
particularconcemto crocodilianhusbandry'
SEX DETERMINATION IN \ERTEBRATES
in amniotevertebrateswas
ft *.r"n model of sex determinationand sexualdiferentiation
gonadalsex of
"
n 1947by Alfred Jost. In mamrnals,birds, and somereptiles'.the
n.JJ*f"t"a
last
fej izationby the presenceof-specificckomosomes(Fipgre l)' In the
; fit"a
,f,"
"rU,l,"
"
hasbeenmadeat identifyingthe cascadeofgenetic eventsthat lead
,"martutte progress
Jecuae
presenceof
in mamrnals.Developmentofi testisis determinedby the
a""-it"tiori
i.
as sR1
known
fador
""r"a
*o.e .p"cifi"uuv, the genefor testis-determining
;i;;;;;;;";;,
for reviews)'
ining tegion Y (seeCapei' 1996and Gustafsonand Donahoe' 1994
fo.,"t-al"t
an
ovary' In
of
of"Sni *t" so-called"default" pathway is the developrnent
ir ,1"
SOX' or SRI"Ut"t""
sex determinatiorLSRf aswell as other genesrelatedto SRl' suchas
mammJian
er a/' 1996;
(daSilva
in the rnalecascade
r]fit;'d lilc
;"""" and Dcr.t, may also be involved
of the
Zr"p*tit-"iii"isriiii"
"t
in thedevelopment
important
it.,1998).othergenes
l?5
maleard femalephenoq?eareSF_1,o. steroidogenia
factor l, whichplaysa key role in the
generegulationof severalsteroidosenic,enz,,rnes.
andproteinhormon" <iilii,
, tgg2;Lynch
et al., t993: Sher.e-td1.,,1994),
"t.
th; p4j0 sieroidogenic
enzymearorn",ir"lliso_orn;,
_a ,f,.
proteinhormoneMiillerianInhibitjneSubstance
u groffh fu"tor_iikJ-hormone
1M1,g1,
produced
bJ the s€rtoli cerrsrhatcauses
them-orphological
iex dead'ofthe r',ari1i";uiau"t;'n it" uuruo"",
the Mtillerianductsfolm oviducts,uterus,andthe uppervaginaand
tf," Woffu* ductsregress
(Cateet q1.,,1990).Analysisindicates
that Sfr._fis requireaior steroiOog"nJ;. rnurn_a, una
is expressedat the earlieststagesof lrogerttal
"d;;;ion of the gene
_"d_;";"";i"p;;;;
encodingSF-Jresultsin newbomsrharlactcadrenal
€tinds anaE iii iiiiL
1994;Luo
et dt., t994a Shen?/ a/., 1994). Borh mateandfema.le
"t.. with SRf
;p;;
JF._,t,
promoungupregulationof,lF-1 transcriptsin males,while".it;;
the absence
-"Ai,
oi.gRl iesults in a
of S.F-l^]nfemales;shortlyafrer diferentiationof tf," S".toli
gecr.ea:e
and formationof
testicular
cords,JF-1expression
persists.in.males
butceases
in fem.f",Or" ,l
1994b).It is
importantlonotethat sJr-.ris expressed
io b.an unais ess"ntiuriorlte Efi"ltion"f,orururonuctei
knownto be importantin reproduction
(Ikeda et at., lg95\.
CENOTYUC SEX DETERMINATION
tellilizrio
v
cd,it
Ddmining
cq6
o@d
'->.dmdd
-+
--
dctlDG -*
*1d
. .
3m#"
TEMPERATT'RI.DEPENDEMSEXDETERMINATION
+
-
iS";LT*3g'*' -'-
Figure L Schernatic
representation
of our
nff$Hffi]u*,
C@d
F(nmrid -l>
-"
d@oM
Sesal
->
Ditr-sni.rid
of rhdo$e
eventsin genotl?ic
sex aletem[nation(top) and
.Tod:l 9l .naJor.exdetermination
Thismodel
Oonom).
could
iniua"-iii:ii"r,i"i, lu* to. irri,i* to
In temperature-dependedt
sex determination(TSD) gonadalsex is not s€t by the genetic
composidoninhedtedat fertirizatioq but rather dependsorithe incubation
iemperatureactivatrng
a genetically programmed sequenaeof develoimantal
. J-urinf a sleUfic period of
embryonic.dev€lopment
(Figurel). Althoughtil a"t".ri"-i,
"u"n
Jr anottrerarestill
beingidentified,
somemajorfaatorsin sexdJtermination
"ii"""sei ,riayasotctuae
in tSO ven"U.ate-s
tf,e
same or homologousgenesas those identiffed in mammalian
,"* a"i"rrninuiion and gonadal
differentiation. In the sliderturtlq estrogenreceptormRNA is in
higherabundancein the genital
ridge at the begirmingof the tempe.ature-sensiliveperiod
in eribryos ai a mate_producing
temperaturecomparedto embryosat a female-producingtemperature,
panem ts reversed
but this
-it"rlady,
during the temperature-sonsitiveperiod (Bergeror er ,il,
isii).-*,e
there arc
developmentaland temperatue diiferences in
alst iOution
uUuiaun"" of aadrogen
"ni
116
receptor hRNA (T. Osborneand D. Crews,unpublished). In the alligator and the red-eared
sliderturtle, there is an increasein ,9OX9mRNA two-thirds of the way through the temperaturesensitiveperiod in embryosincubating at a male-producingtemperatureand not in embryos
inobating at a female-producingtempe8ture at any stage(Westeme/ al, 1998; Spotilae, a/.,
1998). This suggeststhat ,9OX9 is not dilectly regulatedby temperaturebut rather has a
regulatorcontrollingit eitherdirectly or indirectly. In the slidertutle, SF-J
temperature-sensitive
has been identified (Wibbels et al, 1998) and its mRNA found to be more abundantat the
beginningand during the tedperature-sensitivein urogenitaltissuesof embryosincubatingat a
male-producingtemperature(A. FlemingandD. Crews,unpublisheddata). Thereappea$to be
differentialexpressionofP45OarommRNA levelsin the developingbrain ofthe red-earedslider
during embryogenesisaccording to incubation temperature@. Willingham and D. Crews,
unpublisheddata);interestingly,thereis no evidenceofgonadal exp.essionor P450aromwhereas
period. Further, SF-1 rnRNA is
it is evident irl the POAH during the temperature-sensitive
presentat the begiming of the tempenture-sensitiverrindow in the POAH (A. Fleming and D.
Crews,unpublisheddata). A hFothetical se4uenccof the action of ternperatureis depictedin
Fisure2.
l"o**i
lv
'f''
|
l+^T"^"
|
IV
I
Estroeen
/-
|
t,'
J"r'
sequence
Figuae2. Hypothesized
of aclionsof inclbalion temperature.Iacubationrcmper:rtueinllue[cesthe
of steroidogenic
factor I (SF-l) which in orn upreellatesthe s\pressionof the genecodrngfor
expression
tlrc en4me cntical in 1}e sj.ithesisof eslrogen.Tbls estrogenin tum bindsto the eslrogenr€ceptor
aromatase,
rEceptor.
Incubation
temp€rature
alsohasa dire.dymodulates
theeryresslonof € estrogen
@R).
STEROID SYNTTIESIS DURING EMBRYONIC DEVELOPMENT
Steroids are not gene p.oducts, so ifsteroids are important in TSD, rhe mechanismmight involve
diferential responsesto temperuture of steroid-converting en4'rnes (which are gene products).
The biosynthesis of ardrogens and estrogens from cholesterol involves the action of sevem.l
(IISD), reductase,and aromataseenzymes.
enzyrnes,including hydrorfstercid dehydrogenases
Until recendyit was believedthat in mammalsthe fetal gonad was quiescentsteroidogenically
until it diferentiatedinto a testisor ovary. In this scenariothe hormonesproducedby the distinct
testes or ovariesthen acted to sculpt the many ditrerencesbetweenmales and females. It is
known that the testesdeveloDbefore the ovariesdiferentiate. and beein to secretetestosterote
111
(T) coincidentallywith the ditrercntiationofthe Leydig cells and precedingmasculinizationofthe
urogedtal tract (Gondos, 1980; Georgeand Wilson, 1994). Thus, it was believedthat until
gonadaldiferentiatio4 enzrmaticactivity and steroidbiosynthesiswas similar betweenthe sexes
0'y';levJichet al., 1977' Georgeet ql., 1979). There is now evidencethat gene expressionand
steroidogenesis
beginsprior to gonadaldifferentiation.
Using reverset.anscdptase-polymerase
chain reaction(RT-PCR) to study the ontogenyof
expressionof the genesencodingfor four of the steroidogenicenzymesnecessar5r
for androgen
andestrogenproduction@+socholesterolside-chaincleavage,3p-HSD,P.rso17cr-hydroxylase/C1720 lyase, and Pa5oaromatase),Greco and Payne (1994) report inc.easeddRNAs for these
steroidogenicenzFnesp.io. to gonadaldifferentiationin the lat, but only 3p-HSD mRNA was
presentin some of the olzries examined,and the detectionof transcript for the other erzymes
rarg when comparedto ma.les. This suggeststhe characteristiclow ovariao steroid homone
productionresultsfrom the lack of expressionof enzlmesnecessaryfor androgenand estrogen
biosFthesis. Interestingly,both male and female rat fetuses expresstranscripts encoding5areductase@erman et al., 1995). In chickens,there is no sex diference in the abundanceof'
transcriptsofthe genecodingfor 17cr-hydrorylase
prior to gonadaldiferentiatio4 but aromatase
rnRNA is more abundantin putative ovaries comparedto putative testes (Abi\awanto et dl.,
1996:Yostndaet dl., 1996).
In eggJayng ve.tebrutes,including crocodilians,the egg yolk is a rich repository of
hormonesand their precursors@em, 1990; Brown and Nunez, 1994; Conley et al., 1996).
Further, all ofthe steroidogenicenzymesnecessaryto p.oduce sex steroid hormonesare present
in the urogenital systemof embryosof TSD species(Merchant-Lariosand Villalpando, 1990;
Pieur et al., 1994a,b:SmithandJoss,1994; Thomaser a/., t 992), suggestingsteroidbiosynthesis.
Standardhistochemicalmethodshave assessed
the activify of3p- and l7p-HSD enzlnnesat the
begindng, during, and a.ftersex determinationat both ma.le-and female-producingincubation
temperaturesin the red-earedslider (Thomas et al., 1992). Male- and female-producing
incubation temperaturesrcsult in different pattems of HSD aaivity io the adrcnal and
mesonephrosduring development. Significandy,reactionproduct is not observedin the genita.l
ddge at the beginningofthe temperature-sensitive
pedod at eitherinobation temperature,no! is
it apparentin the ditrerentiatinggonadsin embryosduring tempe.alure-sensitive
period; the only
activity detectedin the gonadis observedafter the temperature-sensitive
pedod. This pattem is
also seenin the Olive Ridley seaturtle Melchant-Larios and Villalpando, 1990) and saltwater
crocodile (Smith and Joss, 1994),but not in the Europeanpond tudle (pieau et at,, 19944b).
This suggeststhat in the red-earedsliderturtle, tissuesproximateto the gonador elsewhere,such
as the braiq may produce steroid hormonesat the beginningand during the sex-determining
pedod.
A largebody of evidencefiom all major lineagesof non-mammalian
vertebratesindicat€that
steroidsplay a pivotal role in the sexdeterminationprocess.In particular,exogenoussteroidscan
override genetic and temperatureinfluencesand causec4mpleteand functional sex rcversalin
manyfish,amphibians,
andreptiles@ums,1961;Lam, 1982;Witschj,1959;Crewse, al, 1988).
E>.:tensive
researchin turtles andcrocodiliansindicatethat steroidhomones are the physiological
equivalentofincubation tempenturq direatingsexdeterminationin thesespecies.
r78
lntemalEnvironment
rst og*s->
An&ogen
+OYAR
-tesns
-ovary
Non-aron____>
.Anorogens +TESTIS
5) Estrogenetrectis dose-dependent.
Femaledeteminqtion:
1) Estiogenandaromatizableandrcgens
producefemalesat a maleincubation
remperarure.
2) Aromataseinhibitorsblock female
developmentandinducemale
developmentat a female-producing
tempelature. Administrationof
inhibitor at
testosteroneplus arornatase
female-producingincubationternperature
blocksaromatizableandrogen-induced
feminizarion.
3) Critical periodfor estrogenefect overlaps
withtemperature-sensitivewindow.
Mdle delermindtion.
l) Nonaromatizableandrogensproduce
malesat a thresholdincubation
temperatue.
2) Reductaseinhibitorsblock male
developmentandinducefemale
developmentat both thresholdandmalebiasedinobation temperatures.
Administrationoftestosteroneplus
reductaseinhibitor at rnale-producins
temperatureresultsin femje hatchliigs.
3) Critical period for DHT etrectoverlaps
withtemDerature-sensitivewindow.
via an
4) Androgenic
ligandsmasculinize
receptor.
androgen
5) DHT efect is dose-dependent.
4) Esrrogenicligandsfeminizevia an
estlogen-specifi
c receptor.
of temperature
is transduced
intodiferentconcentralions
of steroidhomones
Figue 3. Thephysicalstimulus
depicted
in dreligurewls conalucted
on
*hich in hrmdircctrhesooaldevelognent
oftheembryo.Theevidence
thered-€ared
sliderturtle.
Even beforewe setdedon the red-earedslider asan experimentalmodelin 1987,Jin Bull and
David Crews developedthe hypothesisthat the physicalstimulusof temperatuteis transduced
into an endocdneprecursorssignal that directs the sex determinationprocess: specifically,
cascadeand bhibit the maleestrogensand their aromatizablestimulatethe female-determining
detemining cascade,whereas nonaromatizableandrogens stimulate the male-determining
cascadeand inhibit the female-determiningcascade(Crews, 1996; Crews et dl., 1994). The
primary support of this hypothesisis summarizedin Figure 3. Five ditrerent approacheshave
yielded datathat strongly suggeststeroidinvolvementin TSD in the red-eareddider turtlg and
probably in crocodiliansas well. ELg!, by using various metabolites,it has been possibleto
identify rhe enzymesand prefered bios,'ntheticpathwaysfor steroid production. Thesedata
indicate that the l7p-HSD detected at the beginning and during the temperature-sensitive
window is an operationalbios',ntheticpathway. Second,preliminaryresults with JeanWilson
l'19
indicate that T is presentin the adrenal-kidney(mesonephros)-gonad
(AKG) complex at th€
beginningand during the temperature-sensitive
window, but not afterwards,in embryosAom a
male-producingincubation tempenturq and is not detectablein embryos from a femaleproducingtemperatweat thesesameembryonicStages.f!i4!, useof specificenzfme inhibitors
indicatesthat both arcmataseand reductaseare activeduring the temperature-sensitive
window.
Fourtll enzyrnekinetic studiesindicatethat both axomatase
and reductaseare presentduringthe
temperature-sensitive
window and that reductaseactivity is higher tha.|l aromatasethroughout
this period in embryosat a male-producingtemperature. Eifth, simultaneousadministrationof
DIIT and estradiol causesthe developmentof ovotestes,indicatingthat male and female sexdeterminingcascades
arc separate.
Although ovarian sex detemination in the red-eared slider turtle normally involves
estrogen,exogenousestrogenscan be viewed as a toxicant if they are presentin supranorma.l
levels during the period of embryogenesis
that normallywould lead to male development. The
red-earedslider turtle embryo is extremely sensitiveto exogenousestradiol. For example,
experimentsexposingturtle embryosto estrogensat incubationtemperaturcsthat produaeonly
malehatahlings,resultin significantsex-reversal.At 260C, a doseof0.5 pg (equivalentto 0.04
ppm) ofestradiol, or 0.05 pg ofE3 (equivalentto 0.004ppm) producesa significantsex-reve$al
efect in eggsandat 28.6'C the effectivedosageofestradiolrcducesto 0.4 ng (lessthan0.0004
ppm or 0.04 ppbillion). Thus, the red-ea.edslider turtle model systemhas proven to be a
seNitive in viro indicatorofestrogensandtheir mimicsin the environment.
SITE AND MECHAMSM OF STEROIDACTION
Without specializedreceptorsto detecttheir presence,sex steroidhormonesor their mimicswill
haveno effect on the animal. Sex steroidhorrnonercceptorsare locatedin the cell nucleusand
comprisea family oftra.nscriptionalfactors that bind to the DNA. There are multiple forms of
receptorsfor eachsteroidhormone,for examplethe a and p folm ofthe estrogenreceptor(ER).
Typically thesereceptolsarc localizedin sp@ificorgaossuchasthe liver or the oviduct, as well
asin boneand skin andthe limbic nucleiofthe brain.
The affinity ofnumerousenvi.offnentalestrogensfor bindingER is rr'eakerthan the natural
sex hormoneestradiol .rKora.het al.,1988; White e/ a/., 1994;Klotz et al, 1996). However,
the biological responsesproduced by some of these estrogenicchemicalsare equivalentto
estradiol, albeit at higher concentrations. For example,the sex-reve$al of turtle embryos
incubatingat a male-determiaing
tempe.aturewith high concentrationsofthe hydrorylatedPCBS
'1994).
was equivalentto the efects of exogenousestradiol(Bergeronet al.,
Futhermore, the
induction ofvitellogenin in maleffsh carlbe inducedto the sameext€nt with estladiol or 1,000fold greaterconcentrationof octylphenolor nonylphenol(Joblingard Sumpter,1993). This has
also beenobservedfo! o,pi-DDT and coumestrol(Pelisseroel a/., 1993). TheseobseFations
suggestthat eventhoughma.nysyntheticor naturalchemicalswith estrogenicactivity haveweak
ER bindingaffinity, they are capableofproducing aatuty i,t riro that is similarto estradiol.
BRAIN AS TEMPERATURE SENSORAND COMMUNICATION LINK TO THE GONAD
How does the embryo sensetempenture and how does this information get tmnslated into
signalsthat activate one genetic sex-determiningcascadewhile inhibiting the other? In all
vertebrutes,including mammalsand reptiles, there are tempenture-sensitiveneurons within
preoptic area-anteriorhwothalamus(POAH) (CabalLac
et ql. 1967;Rodbad et ql. 1950;Heath
180
et al- 1968)- In additionto being a mastercontroller of thermoregulation(Satinoq 1995),this
samearcacontamsneuronscortainingsexsteroidhormonereceptors. Researchwith a variety of
TSD species indicate that when ternperatureexerts its effect on sex determinatiorLthe
period, and gonada.ldifferentiationare not efltirsly coincident. In turtles
temperature-sensitive
period of gonadal
the diencephaloodifferentiatesat the sametime as the temperature-sensitive
development(Senr\ 1979), and Merchant-Larios(1998) has suggestedthat the signal for sex
determinationis extragonadalandthat the histologicaldiffercntiationofthe gonadis a secondary
effect. In supportthis hypothesis,they repon that at the beginningofthe temperature-sensitive
period the hypothalamusof embryosfrom a presumptivefemale-producingtemperaturehas
higher levels of estradiol in comparisonto embryos from a presumptive male-producing
temperatwe. Interestingly,and consistentwith researahon other TSD species,estradiollevels
were not different in the gonadsor serumbetweenembryosofthe male- and female-produchg
period. Sirnilarly,in the diamondbackterrapir!
temperaturesduring the temperature-sensitive
aromataseniRNA expressionbegins prior to the sex-daermining period of developmentin
period,
presumptivefemales;theselevels declhe until, at the end ofthe temperatu.e-sensitive
aromataselevels are higher in the bnin at male temperatutesthan they are at female
ternperatures:administrationof exogenousestradiolappearsto depressatomataseexptessionin
the brain at maleincubationtemperatures(Jeyasuriaard Place,1998).
In vertebratesthere are direct neuralconnectionsbetweenthe gonadandthe hlpothalamus
(Crews, 1993), ard consistentwith the hypothesisthat the brain communicatestempenture
infomation to the gonad via this link (Merchant-Larios,1998) is the observation of neural
inneration ofthe embryonicgonadin turtles (Merchant-Lariose, al, 1989).
TRAD]TIONAL TOXCOLOGICAL VS, ENDOCRINEDISRUPTORPARADIGMS
paradignsare changingaswe leam more abouthormone-likechemicals(Figure
Risk assessment
4). Lake Apopka in Florida hasbeena classicexampleof how environmentalcontaminationcan
affect reproductivedevelopmentin alligators.
Traditional
approach
.
.
.
.
Endocrine
approach
disruptors
developmental
model
delayeddysfunction
no threshold
synergisticeffects
carcinogenic
modgl
mortality/acutetoxicity
threshold
additiveeffects
andthe
approach
to dsk assessment
in thehdicesthatrnarkthetraditional
toxicological
Figure4. Diffe€nces
forendocrine
di$uptingchemicats.
newlyenergtng
approach
The resemblance
ofgonadal and penileabno.malitiesof the Americanalligator in Lake Apopk4
(Guillette
a al., 1996) to those describedin mice trcated with the potent, synthetic
Flodda
estrogendiethylstilbestrol(Mclachlar et al., 1980),led to detailed studies documentingthat
by a chemicalspill of dicofol was the most
chronic pollution by agriculturalrunoff exacerbated
likely causeofthe reproductiveanomaliesobservedin the alligatorsoflake Apopka (Guillettee/
al., 1994). Dicofol and its components,havebeen shownto bind the ER ftom the Amedcan
alligator (Vonier et a/,, 1997), and therefore,may function as an estrogenin the alligator. Io
additionto DDE/DDT contamination,a variety ofother pesticideshavebeendetectedin alligator
eggs,includingdieldri4 toxaphene,ciVtransnonacl or, arachlor,chlordaneand pp'DDD (Heinz
181
et dl., 1,991\. Ex?osureof alligator(Guillette,unpublished
data)and red-ealedslid€rtunle
(WillinghamandCrews,1998)embryosto concenhations
ofthesecompounds
typicallyfoundin
natureresultin anomalous
reproductive
(Figue
development
5).
100
90
80
X60
6
430
20
0 J---r-.J-J--IEl1l-+-:.E
,,"t"
".t
$6
."d
*'" nslg'C
gn fu
iv
pu
usB ut"-- s^d .s''
Figure 5. Efect of exogenous
liganalson sex determinationin the rcd-earcdslider turtle, Trachenlsscripta
e/zAair,showingp€rcentrei€rsalfromeachtreatmentAll eggsincubated
ar 28.60 C. Compounds
w€reassaFd
aloneand in combinationwith 0.0l|rg estradiol.Percentrei€rsal for negative(solventonly) control ad E2
controlalsosho\rn.Nunbersin barsindicate$mple size, * indicatessigificant re!€rsalrersrrsnegativecontrol
for compoudsappliedsingll a indicatessignifica reversalversuspositivecontrolfor compounds
appliedirr
cambination
with estradiol.(fiom Wi[inghamandCrelis, 1998).
The diffculties in demonstrating a clear cause-and-effect relationshiD between endocdne
disrupting chemicals and reproductive anomaliesarises from the fact that thi wrong yardstick has
been used. Environmental toxicological paradigns typicatly focus on high phannacological
dosage exposure to adult individuals resulting in mutagenesis, cancer and death as unequivocal
indications of contaminant efects. Endocrine disrupting chemicals, however, are characterized
by a delayed respoasg often measuredin years. between exposureto low physiologicallyrelevant dosagesduring sensitiveperiods of organ developmentin the embryo. Thus while
traditionaltoxicological paradignsrequire a clear causalrelationshiptraceablefrom exposureto
the developmentof a canaerand deatl\ what we are conftonted with is functional sterility
resultingfiom the bioaccumulationof chemicalsthat persistin the environmentat relativelylow
levels.Two otier notablefeaturesofendocrine-disruptingchemicalsis the (i) synergisticactions
ofnatulal estrogensandtheir syntheticmimicsresultingin reproductivedysfunction(Bergerone/
al., 1994, l99a A'I.old,et al., 1997\, and (ii) recent evidenaethat the concept of a threshold
dosagedoesnot applyfor endocrine
disruptors(Sheehan
et a/., 1998).
182
Stnergislic qctions of hydroxylatedPCB,. Synergismoccurswhen the eFect of two facto$
togetheris greaterthan the sum ofthef efects when given separately(i.e., greater-thal-additive
effects). Curent controve$y conceming environmentalestrogensis whethe. they exhibit
slnergistic activity. A numberof sldthetic compoundsmiftic estrogens,althoughwith a lower
potency than natural steroidal estrogens(Soto el al,, 7994; Mclachlan, 7993; Korach et al,,
1988). When consideredindividually, these ahemicalsmay exist in the environment in
concentrationstoo low to be of concem. In combinatior\howev€.,low dosagesof thesesame
compoundsmay act slnergistically to produce a strong estrogenicresponse. This low-dose
sJmergywas fint shown with polychlodnatedbiphenyls@CB$ using an iz yryo sex-reve$al
assayi[ the red-earedslider turde @ergeron et al., 1.994). As metabolitesof other pCBs,
hydroxylatedPCBSmay exist in steady-statecoqcentralionsin aquaticenvironments,potentially
exposingwildlife to thef efects via direcl contactor tkough the food chain (McKinney et a/.,
1990). The applicationof some PCBS can act as estrogensard override a male-producing
temperatureandreversesexpresumablythroughthek actionon gonaddete.mininggenes. Using
the all-or-nothing nature of the responseof red-earedslider turtle embryos to exogenous
estoger! we assayedI I cormon PCB'S(Bergercnet al ., I 994) Or y two of the compounds
tested, 2',4',6'-trichloro-4-biphenylol(3-PCB) and 2',3',4',5'-tetrachloro-4-biphenylol
(4-pCB),
were found to haveestrogenicactivity as indicatedby the productionof femalehatchlingsfrom
eggs inobated at a male-producingtemperature. It th€se instanaesonly the high dosage
producedfemalescompletewith fully developedoviducts.The former compoundshowed100%
sex reveGal at 100 pg or just below 9 ppm. In tests using mouse tissue, these sametwo
compoundsshowarl appreciableaffinity for ER, due in part to their conformationalpropertiesas
hydrorybiphenyls (Korach €/ a/., 1988; McKirmcy e, al., 1990\. Becausepurified PCB
compoundsare rarely found in the environment,we decidedirr the secondsedesof expedments
to look at combinationsof the samePCBS. All eggswere incubatedat 27.8 oC and receiveda
low (10 ;rg), medium(100 Fg), or high (145 - 190 pg) dosageof compounds.Someeggs
receiveda cocktail ofall PCBSexceptthe two which causedsexreversal(3- and4-pCB). Others
weie exposedto combinedhydrorybiphenyls,againexcluding3- and 4-PCB. Lastly, someeggs
were treatedwith combinednon-hy&oxylatedPCBSwith no evidenceof sexreversal. Sincewe
knew 3- and 4-PCB showedestrogenicactivity at the slighdyhighertemperature,we decidedto
try thesetwo compoundsat a temperaturetiat produces100%nales (26 "C). Both compounds
showedsignificantsex reversalat this temperatule. When combined 3- and 4-PCB si'nergized,
resultingin a signifcant iocreasein ovariandevelopmentat a dose of 10 Fg or lessthan I ppn!
whereas3-PCB alone aod 4-PCB alone required at least a tenfold higher dose to show sex
rwersal. Exogenousestradiolproducessimilarresultsat a doseof 0.5 !rg, or .04 ppm (Wibbels
et ql..1991\.
183
lootqc
2@F F
Trcatment
2@!g G
lotg FIG
lootg F+G
FigEe 6. Percentof female hatclilings at a tempembr€ which nomally producesl00o%rnales(26 oC)
following lreatment with two estsogenicPCB compoundsin ethanol. Controls: lemperature-ethanol
alone; hormone- l0 }g esrradiol-l?p. PCB compourds: F = 2',4',6!tdchloro{-biphenylol; G =
2r,3r,4r,5r-tetrachlorc-4+iphenylol.Signifrcaft ssx rci€rsal is indicaled by . pO 0.03; *1 !F 0.003; 'ltr'
F 0.0001. Redrarm from Beryercn et al., 1994.
The concept of a lhreshold dosagedaesnot apply/or endocrinedisruptors. Traditionally,
dsk assessmentsare founded on a carcinogenicmodel characterizedby indices of acute
toxicity/mortality, the presumptionof additivity of chemicals,and the existencefor every
chemicalof a thrcshold dose below which no adverseeffects ocaur. Gaylor e/ al (1988)
suggestedthat this assumptiondoesnot applywhen an endogenouschemical,suchas a hormone,
reachesa sumcient concentrationto causear effect. In such aases,the theshold for the
endogenouschemicalis alreadyexceededand, therefore,no thresholddose exists for a mimic.
We testedthis h]?othesiswith the red-earedslider and demonstrateda biologicallybaseddoseresponsemodel for developmental
toxicity. First, analysisof oul publisheddataon the etrectsof
varying dosesofestradiol at ditrerentincubationtemperaturesrevealeddose-lesponse
cuivesthat
fit a lvfichaelis-Mentenequatioo. A power-analysisapproachwas then used to conduct a large
Q400 egg dose-responsestudy designedto test whether the threshold hypothesisappliesto
estradiolin tiis arima] model system,and to detemine whether the l\4ichaelis-Mentenequation
canpredict orgarismalresponse.This equationprovidedan ED56of 5.0 with a 95% confiderce
limit of+2.0 ng (endogenous
dose= 1.7+ 1.3 rtg exogenous
dose= 3.3 + 1.7rg) andan I =
0.90 for fit of the modifiedMchaelis-Menten
equation.. The lowestdose,0.4 ^gl0 E egg,
significandyinseased the femaleAaction by 11.4%. Ar important feature is that the curve
becomesincreasinglymore Iinear as dose decreasesrelative to EDro, reinforcing the failue to
find a thresholddoseby an empiricalfit. A replicationof the studywas conductedthe following
year with similar results. The resultsindicatedthat both past and current studiesof slider sex
reversalat arr organismallwel (i) can be flt to a Mchaelis-Mentenmodel of a single proteinmoleculeinteraclion driving a reversibleprocesg and (ii) rweal no thresholddosefor chemicals
concefltrations
actingthrough the samemechanism.Thusit may be that evenlow environmenta.l
recepto!-depeldentchemicalswill carry risk.
of endocrine-disrupting,
CONCLUSION
As the complexitiesof interactionbetweengenes,honnonesand hormonerecepto$ during sex
determinationbecomebetter unde$tood, the di$uptive inJluenceof man made compoundson
normal sexual developmenthas emergedas a serious concem for cooservationists, ildlife
managersand crocodile farmers. Compoundscapableof interfering with normal development
havebeaomeubiquitousin naturalenvironmentsandbecomeconcentratedby bioaccumulationin
natual food chains. LongJived organismsfeeding at the top of the food chai4 such as
crocodilians,are particulady!'ulnerableto acaumulatingheaty burdensof contaminants. The
studiesreportedand reviewedhereindicatethat while thesecompoundsmay not affect the adult
organisn! they aanbe passedto the egg yolk where they are potent at extremelylow dosesin
disruptingnormalsexualdevelopment.
Recentlyit hasbecomeevidentthat assumptionsaboutadditivity andthresholdsmay not apply
to chemicalsthat mimic the action of ligandsimportant to sexualdevelopment. For example,
there is an increasingbody of evidenceindicating that minute amountsof xenobioticspresent
during early dwelopmentmay not result in cancerand deatl\ but nther alter sexualdevelopment
suchthat the adult caffrct reproduce. Such sterile individualsoccupy spaceand use resources
but cannot contributeto populationgolvth. Similarly, recent studieshave demonstratedthat
certain combinationsof steroidaland nonstercidalestrogensand their mimics are synergistic
for virtually all chemicals
rather than additive in their effects. Finally, curent risk assessments
genotoxic
which
no adverseeffectsoccur
carcinogensassumethat there is a dosebelow
except
(the thresholddose). In practice,the highestdosewithout toxicity is usedas a surrogatefor the
thresholddose. Assessingrisk becomesmore complicated,howwer, when a chemicalmimics
the actionof an endogenoussubstanceimportantin development.It hasbeensuggestedthat this
thresholddose$pothesis carmotapply to rcn-carcinogenicchemicalsthat mimic the action of
impo.taflt in normaldevelopmentsince,upon exposure,the thresholdfor
e[dogenoussubstances
the endogenoussubstanc€is alreadyexceededand, thelefore, no theshold dose exists for the
mimic.
ofthese effectsto crocodilianconservationmay be profound. In the best
The consequences
studiedexampleon Lake Apopk4 Florid4 low eggviability resultedin the reductionofjuvenile
cohortsandthe distortionof sizeclassdistributioN extendingfor manyyearsafte. the presumed
causalevent (Woodwatd el qL 1993). Even as the wild alligator populationbeginsto rccover
from this setback (Rice, 1997), lesearch indicates that many of the surviving juveniles
demonstrate impaired gonad functior! abnormal hormone levels and ambiguous sexual
morphology(Guilette et al., 1994). lvhether theseindividualswill eventuallymatureandrecruit
to the breedingpopulationrcmainsto be seerLbut appearsunlikely.
Crocodilianconserntion prognms worldwide havebeen establishedon sustainableuse and
harvestprogams (Ross 1996, 1997 a.). Theseprogramsin tum are basedupon demographic
models and assumptionsabout reproductiveeffectivenesswhich determineharvest levels and
provide the basisfor the resiliencyof crocodilianpopulationsto modestlevels of harvest. If
subtle efects of biogenic compounds cause abnormal sexual development and impaited
reprcductive capacity, the foundation of these programs will be challenged. Crocodilian
populationswhich demonstratemore or lessnormal densitiesto superficialfield survey,may in
fact not be reproducing.
185
The consequences
to crocodilianenching ard farmingeforts are also obvious. If the subtle
effectsofcontaminantsin the environmentreduceeitherthe quantityor quality ofeggs collected
from the wild ranchingprogramsor obtainedfrom captivebreedersthen the economicemciencv
of theseprogramswill be compromised@oss 1997b.) As the continuationof management
ani
conservationactivities is oflen dependentupon economicincentivesfrom cormeroial harests,
both commercialand conservationinte.estscould sufer
Crocodiliar habitatsaroundthe world are associatedwitl drainagesand watershedssubjectto
intensehumansettlementand agricultura.luse,often with poorly regulatedcontaminantco;trols.
While hormonedisruption in crocodiliansis only reponed from a small numberof localitiesin
Florida USA it seemhighly likely that this problemmaybe widespread.As it is ur ikely that the
use of endocdnedisrupting compoundsaan be prevented,and as they are in any casehighly
persistentin the envitonment,aDy.esponseto this new challengeneedsto be basedupon an
understandingofthe complexbiochemistryandphysiologr concemed.
At the field level, we suggestthat the viability of crocodiliar eggsmay serveas a simpleand
readily obtained index of potential endocrine disruption. While other factors may cause
occasionaldropsin normaleggviability, peNistentdrops,associatedwith changesin the gonadal
ald penile morpholoS/ of hatchlingsmay serve as alr adequatemonitoring mechanism. Such
parametencan quite readilybe monitoredin wild populations,ranchegg collectionsand captive
breedingfarms. For the futurg asour unde$tandingof mechanisms
improvesit may be possible
to develop biochemica.linterventionswhich protect the developing embryo from hormone
disruptive effects. We speculatethat it should be theoretically possibleto treat ovigerous
females with compounds which bind and sequesterhormone disruptors and prote;t the
developingembryo. A pannershipbetweenfield conservationists,
commercialproducersand
researchers
in relrroductivephysiologywiu be productiveto meetthis challenge.
ACKNOWLEDGEMENTS
Original researchreportedhereinwas supportedby $ants from the National ScienceFoundation
(IBN-97236U) andthe NationalInstitureofMental Health O,IH KO500135).
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190
PopulationDynamicsof LakeApopka's Alligators
KennethG. Rice,H. FranklinPerciva.l,Allan R. Woodward,aod
Cla.rence
L. Abercrombie
USCS-BRDI
EvergladesNationalParkField Station
40001sR 9336
FL 33034
Homestead,
in thejuvenile
Abstmct:Begimingin 1981,a majordeclinewasobserved
alligatorpopulationon Lake Apopk4 a largefreshwater lake locatedil centralFlorida.
Evidenceexiststhat envircnmentalcontaminationis partiallyresponsiblefor this decline.
viability, andpopulationgrowth on the lakefrom
We examinedclutch characteristics,
partialrecoveryofthe system.Thetotal populationof
1981-1995
andobserved
through1995(P<001) Overthe same
alligatorsdecreased
until 1989thenincreased
period,juvenilesdecreased
by 480%(P < 0.01).
by 95%thrcugh1989thenincreased
80%
1988
and
thenincreasedover
through
Clutch viability deqeasedby approximately
depressed
when
400%(0.l2 to 0.53)though 1995.Horvever,viabilityremained
(Lake
National
Wildlife
Refuge
comparedto a rcferencearea,Lake Woodruff
Woodruff;P< 0.001).LakeApopkaalligato$producedmoreeggs(P = 0.006)per
clutchthan Lake Woodruq but clutchweightsdid not difer (P > 0.05). Lake Woodruff
ploducedmore hatcl ings @ < 0.001)per clutchthanLake Apopka. While many
parametenassociatedwith the alligatorpopulationon Lake Apopkaremaindepressed
when comparedto relativelynaturalareas,signsofpopulation tecoveryfrom
reproductivefailure are now evident.
INTRODUCTION
In the late 1970'sthercwas considenbleinterest&om the Florida Gameand
FreshWater Fish Commission(GFC) andthe alligatorindustryto commerciallyharvest
both adult andearly ageclassalligatorsin Florida. The GFC hadinstituteda nuisance
alligatorprogramandhadembarkedon researchto investigatethe feasibilityof
zustainableadult harveston publicv/aters(Ilines andWoodward 1980). Florida's
eggsandhatchlingsfor captiverearing
alligatorfarmers$r'ereinterestedin ha.rvesting
(ranching)to supplementclosed-system
farming. Alligator farmersandthe GFC
developeda cooperativeventurein 1979to monitor alligatorpopulationsby night light
surveyon 3 lakes(lakesApopka,Grifiin, andJesup)from which hatchlingswere being
harvested.Theselakeswere consideredasdemographicallysimilarlakesin the St.
I Addressfor SeniorAuthor only.
191
Jobn'sRiver drainagehavingdensepopulationsofboth adult andearly ageclassanimals.
Nghtlight surveyscommencedin September1979andhatchlingharvestsbeganin
1981.
In 1981,the Florida CooperativeFish andWildlife ResearchUnit (FCFWRU;
UniversityofFlorida, GFC, andUSGSBiological ResourcesDMsion cooperato$;lhe
U.S.FishandWldlife Servicewasa cooperator
in 1981)enteredintothe research
fundedby the FloridaAlligator FarmersAssociation@AIA) in coopention with the
GFC. A populationcrashon Apopkawasobserved
betweenl98l-1984 in < 182cm
animals(Woodwardet al. 1993). Relativelysmallpod (group ofhatchlings)sizeandan
unusualnumberofunhatchedeggson Apopkawere noteddudng 1982. A low clutch
viability rate (numberhatcMotal eggsin a clutch) of alligator eggson Lake Apopka was
observedin 1983after studiesbeganexaminingthe feasibilityofcollecting eggsrather
than hatchlingsfor ranchingpurposes.Although Apopkawas lessimportantasa harvest
site becauseofthe alligatorpopulationdecreasgth€ lake cootinuedto be a focusof
attentionbecauseof extremedifferencesin hatchratesfrom other lakes. With the
suppo.t of GFC,FAFd andthe AmericanAlligator FarmersAssociation(AAFA),
subsequent
investigationsexpa.rdedresearchto includevariability in clutch viability on a
numberof lakes,includingLake Apopka.
Through1987,long-termtrendsstillindicateda declineinjuvenilealligatorson
Lake Apopka. Meanwhile,other lakesin the St. JohnsRiver drainageshowed
numerically
stableor increasing
alligatorpopulations
(Jennings
et al. 1988,fuce 1996;
Woodwardet a.l.1993). Cont.olledinobation ofalligator eggsindicatedthat Lake
Apopka hadthe lowest clutchviability ratesof any populationexamined@ercivalet al.
1992;Masson1995).In 1988,theLakeApopkaviabilitylate fell to a low of0.04.
Thesedat4 derivedfrom laboratoryincubation,appearto correlatecloselywith events
occurringin tie wild. Investigationsofneonatalwild podsdemonstratedthat Lake
Apopka hadthe lowestdensityofpods andthe smallestpod sizeofall studyareasin
Florida(Percivalet al. 1992).
In 1988,the FCFWRUbeganto investigatecausesofApopka,s low clutch
viability andpopulationdeclines.Coupledwith a studyinvestigatingthe reproductive
physiologyofadult femalealligators,the possibilityofenvtormental contaminantefects
was examined.Lake Apopka hadsubstantialcortaminart inputs from agriculturalrunofi, sewageemuent,ard a major chemicalspill (U.S. EPA 1994). An analysisof
alligator eggscollectedin 1985from 3 Floridalakesshoq/edthat eggsfiom Lake
Apopka had significantlyelwated levelsofDDD, DDT, andDDE (Heinz et a1.1991).
Other studieshavedocumentedincreasedestrcgenicactivity (a possibleeffect of
exposureto envi.onmentalcontaminants)in juvenile alligatorsfrom Lake Apopka.
Other eodocrineeffectsandgonadalabnormalitiesalsowere found (seeRice and
Percival1996).
This studyexaminedlong-termtrcndsin both alligator clutchviability and
populationindiceson Lake Apopka. In particular,the h$othesis ofthe recoveryof a
populationfollowing catastrophicreprcductivefailure is tested. Further,the dFamics of
the Lake Apopka alligatorpopulationare comparedwith thoseofa referencepopulation
from Lake WoodruffNational $4ldlife Refuee.
t92
This studywasfortunateto receivesubstantialfundingfrom manyinstituhons
includingthe AmericanAlligator Famer's Association,the FloddaAlligator Farmer's
Associatio&tlle Florida Wildlife Federation,the Florida GameandFreshWaterFish
Cornmission(GFC), the St. JohnsRiver Water ManagementDistrict, the U.S.
EnvironmentalProtectionAgency,the U.S. Fish andWildlife Service,andthe Florida
Cooperativ€Fish andWildlife ResearchUnit. The project hashadthe luxury of
incolporatingthe expertiseof manyindividualsfrom multiple agenciesover the years.
At the risk of eliminatingmanyimportantlames, thesepeoplealwayshad pride in
referilg 10themselvesasmembersofa looselyorganizedgroup, the Florida Alligator
ResearchTealn. Requidngspecialreferencearethe following: J. Anderson,A. Brunell,
D. Carbonneau,
J- Connors,R. Conrow,D. David,G. Davidson,L. Folmar,M. Fuller,
T. Gross,C. Hope,L. Hord,M. Jemings,W. JohnsoqL. Rhodes,T. Schoeb,S.
Shrestha"R. Spratt,H. Suzuki,C. Tucker,J. Whit€, J. Wiebe,andC. Wieset.
METEODS
Egg Collections
Alligator clutcheswere collectedfrom nestson LakesApopka andWoodruff
fiom 1983to 1993alsowere
dudngthe summeFof 1994and1995.Prior collections
includedfor long term trend analysis.Alligator nestswere locatedvia aerialsurveysand
ground searches.For eachaollectedclutcb nestheight,diameter,ambienttemperature
(thermomete$ were calibratedto a standardized
thermometer),clutchcavity
tempenturq clutch depth,apFoximatepercentageofdaily shade,flooding status,
femalepresenceandbehavior,andnestinghabitatwere recorded. Eachnestwas
completelydismantledandsearchedcompletelybecausemultiple nesting(two or more
femalesovipositingin a singlenest)hadbeenobserved@ercivalunpubl.data).
Disturbedor depredatedclutcheswere not collected. All eggspresentin the nest,
includingdamagedandnon-viableones,were collected.
Eggswere placedirlto plasticbuspans(61 cm X 36 cm X 13 cm) on 5 cm of
naturalDestmaterialwith additionalnestmaterialcushioninglayersofeggs when
required. Eggs alongthe buspanperimeterwere cushionedwith 2-3 cm ofnesdng
material. An identi&ing plasticplant tag was afixed with coppe.wire to a hole in the
comer ofthe buspanim. The order (approximatelyuppermostto lowermosqin which
eggshadbeenremovedAom the nestwas maintained.To ellsurethat datasheetscould
be matchedlater witi clutahes,nestnumber,date,time, andcollectors'nameswere
recordedon the tag, aswell ason the datasheets.Pais of eggsor eggswhich were
found crushedwere sealedin a labeledplasticbag.
Transportationofeggs followed recommendations
by Woodwardet al. (1989).
During transportationofclutches, carewas takento avoid excessivevibration or shock,
from the shell(Ferguson1985).
which couldkill embryosby detachingtheir membranes
Clutcheswere protectedby in{latablecushionsandfoam rubberwithin transpo.tboats,
which were carefullymaneuvered
within shelteredwatersto avoid additionalvibration
andshock. Eggswere transpo.tedto an incubatorfacility in Gainesville,FL within 24
hs ofcollection in the coveredbed ofa pickuptruch which was aushionedlike the
transportboat (Woodwa.det al. 1989).
193
Clutch andEgg Characteristics
At the incubationfacility, carewastakento avoidvibrationand rotation ofviable
eggs. Bus panswereweighedwith andwithout eggsto calculatea clutch weighl. All
intact (unbroken)eggswere transilluminatedto checkfor viability and eggband
development(Woodwardet al. 1989). Anomalouseggs(thosecortaining two yolks,
yolkless,or with aberrantcalcifiedregions)were recordedand,whenpossiblq were
measured.Non-viableeggswere identiffedby t}te absenceofan opaqueembryo
attachmentspot or band. Unbandedeggswere opened,anda visual statusdetermination
was made. Ifband developmentwasvisibly letarded,or ifvascular color wasnot similar
to that ofother, apparentlyhealtht eggsin a clutclL the eggin questionwas openedand
the developmentalageand embryonicstatus(good, weakor deadandpresenceof
deformities)ofthe embryowasdetermined.Onehealthyrepresentativeeggwas
removedfrom eachclutch andsacrificedfor determinatioiofclutch ageandexpected
hatchdate. Crushedeggsandemptyeggshellswere examinedto determinewhetheran
embryowas presentandits developmental
age. Wheneverpossiblg embryoagewas
determinedusing a combinationofback-dating(dateofcollection minusembryoage),an
embryologicaldevelopmental
chart(Masson1995),andeggbandprogression(Ferguson
1985). Eggswere transilluminatedat approximately14-27day intervalsthereafterto
identify and agedeadembryos.Eggsremainingunhatchedat the end ofthe incubation
period alsowere openedard embryoagedetermined.The dispositionof eacheggwithin
a clutchwas recorded.
Incubation
All eggswere incubatedin a modified7.3 m x 3.7 m portablebuildhg (Lark
Industries,FL). Thebuildiog waslayeredfor insulationwith 2.54 cm blown-in foam
insulation,7.6 cm fiberglassbatting,a visqueenvapor barrier, and2.54 cm stFofoam
sheeting.The humidityandtemperaturewere controlledby a HawkheadIntemational
heat/coolhumidifierunit providingcontrolledhigh humiditywarm air. This unit used
merory switchesfor temperahrreandwet-bulbhumiditymonitoring. Thermostatically
controlledeleatricfansaadlouvers,aswell asceilingfanscirculatedair tbroughoutthe
building. The relativewet bulb humidity in the buildingwas 94-960loand mean
temperaturewithin th€ nestsandin the buildingwas 30.6 C ! 0.5. Hovr'ever,nesting
matedalhad to be moistenedwery 7-10 daysto maintainthe appropriatemoisturelevel.
Clutch integ ty ard within-clutchcollectionorderwere maintained.All clutches
were inobated in dampsphagnummoss(a minimumof2.5 cm on top, bottoq and all
sides)in bus pansplacedon shelveswithin the incubator. Eachbuspan was covered
with 50oZshadescreeningcloth to allow air circulationandto contaiohatchlings.To
minimizeprematurehatchingofalligators by audiblecuingfrom adjacentclutahes,
clutcheswith similarhatchdateswere groupedtogether.
Hatcbling Care
Hatchlingswere maintainedin the aforementioned
insulatedincubationbuilding
for approimately 14 daysbeforereleaseat their originalnestsite. The building
contained6 galvanizedalumirumtanks separatedinto 24 individual0.6 m x 0.7 m
194
we.e dividedwith a galvanizedaluminumwall sealed
compartments.Compartments
with latex caulking. Eachcompartmentwason a 3.8 cm slopeto provideboth dry and
wet surfaces.To increasethe dry surfaceareaandminimizestressfrom overcrowding,
an elevatedmeshplatformwasaddedto eachcompartment(2.5 cm squaremesh
constructedfrom moldedplastic-coatedheavygaugewire). Tankswere cleaned
following eachfeedingandrefilledwith freshwater. A maximumof30 hatchlingswas
placedin eachcompartment.Wheneverpossibleclutchintegdtywas maintained
(hatchlingsp.oducedfrom a givenclutchwere maintainedwithin a singlecomPartment).
Eachpe$on working with hatchlingswasrcquiredto washhister handsandequipment
with a Betadinesurgicalscrubaad/ora 3olobleachsolutionprior to beginningand
betweencompartmentsto eliminatecrosscontamination.
Hatchlingswere retaineduntil theywere activelyfeedingaid lhe ertire
compartmentappearedhealthy. After yolk absorptioo,hatchlingswereweb-taggedin
their right hind foot with sequentiallynumbered#l Morcl tags(NationalBand andTag
Co., KY). Throughoutthis petiod, dataon physicalabnormalities,weakness,and
mortalitywere recorded. In 2 vr'eekincrements,thoseanimalspreparedfor release
(hatchlingsthat appearedhealthyandwere eating,etc.) were lransportedto their original
lake in buspans.If 1 or more animalsin a pod were not readyfor release(i.e., weak),the
entirepod was held at the incubationfacility until all could be transportedtogether.
Hatchlingswere transferredto a transportboat ard releasedat their originalnestsite or
the nearestfeasibleand appropriatelocatiofl.
Viability and Clutch Size
Clutch size(CS) wasthe total ofall shelledandunshelledeggsfound in a clutah
cavity. Clutch viability (9 rateswere definedasthe numberofhatchlingssurviving>1
day dMded by CS. Sincethe inherentviability ofeggs was ofinterest, clutchesfiom
flooded or disturbednestsOy predato$,turtles,humans,or other alligators)werc
excludedftom viability analyses.Or y clutchesftom disturbednestswere excludedfrom
analysesofCS. A singleclutchwasthe sampleunit in analysesofV and CS.
SurveyProcedues
Night-light surveyswere conductedin lateMay or earlyJuneon lakesApopka
andWoodruffin 1994and1995. Suweysfrom 1980to 1993fiom LakeApopkaand
198l-1993for LakeWoodruffalsowereincludedfor longtermtrendanalysis.
Nightlight surveys(2/yearin mostyears)were conductedin lateMay or earlyJune.
Surveyroutesgenerallyfollowed the openwater-shorelineinterface(Mutphy 1977;
woodward andMarion 1978). Densemarsh,woodedswamp,andother inaccessible
alligatorhabitatwere not surveyed.The entirecircumferenceoflake Apopkawas
surveyed.On Woodru{ only selectedcaoalsandqeeks were surveyed.However,in
eachcase,surveyswere standardizedacrossyears.
Searchesfo. alligatoreyereflectionswere conductedwith an airboatat a planing
speedof20-25 kr/hr, dependingon rtater conditions. Whendensegroupsofalligators
werc encountered,the airboatwas sufficientlyslowedto allow a thoroughcount. A
200,000c.p.spodightwasusedandsizeofdetectedalligatorswasjudgedas
195
approachingthem at normal surveyspeed.
To estimatealligator size,both the snoutlengthJotallength (TL) index descdbed
by Chabreck(1966) anda generalimpressionofsize, periodicallycalibratedby catching
andmeasuringsize-judgedalligators,we.e used. Alligatorswere classifiedin 30cm
(1-ft) sizeclasses
whenpossibleor placedintobroaderTL categodes
(0-60cr4 6l-121
aft\ 122-182cm,<722 cm, and<183 cm; WoodwardandMoore 1990)when specific
sizeclasscould not be determinedbut other indicationsof sizewere evideDt(g&,
habitat,eyereflection,bubbletrails, sizeof splashor wake). Sizewas classifiedas
"unknown" whenno indicationof sizewas apparent.
Water levelswere recordedfrom U.S. GeologicalSurveywater levelgauge
statioosin permanentlocationson the rnainwater bodies.The "water level',ana.lyzed
for
eachsuryeydatewas departurefrom meanwater levels(DMWL) for all surveys(see
WoodwardandMoore 1990).
Suney Analysis
For trend analysis,the sizedistributionofunkno$n-size alligato.swas assumed
consistentwith the distributionof known-sizealligators(assumedequaldetectability
amongsizeclasses).Unknown-sizedanimalswere apportionedaccordinglyin 4 TL
<30 cm ("toralpopulation,,),
classes
[30-l2l cm ("juvenile"),122-182cm("subadult"),
<183
and
cm ("adult")l(seeWoodwardandMoore 1990).Duringthe May-June
surveys,hatchlingsftom the previousyear(approx.9 monthsold) were consideredto be
sufticientlydispersedto rendertheir sightingprobabilitiesasindependentandwere
includedin the analyses.
For Lake Woodruq testsfor trendsin count densitieswere conductedby
regressinglog-transformedcountsofalligators in eachgeneralsizeclasson elapsedtime
andDMWL. DMWL v/aspreviouslyfoundto explaina significantproportion of
variationin night-light surveys(WoodwardandMoore 1990). For Lake Apopk4 both a
model similarto that utilized for the Lake Woodruff dataanda non-linearmodelwere
fitted to log-transformedcountsregressedon elapsedtim€ a.ndDMWL. The nonlinear
segnentedmodelincorporatedboth a quadraticanda linearresponseto test for possible
inqeasingtrendsdudng recentyea$. In all cases,the quadraticportion ofthe model
was specifiedfirst dueto the relativeamountofdata (yearsofsurvey) beforeand after
the lowest count (the quadraticsegmentrequiredthe estimationofan additional
parameter).We allowedthe modelestimationprogram(ProcNLIN, SAS Institutg Inc.
1988)to choosethe point wherethe two segmentsmetby imposinga continuity
rcstriction orl the model. We specifiedthat the quadraticandlinear segmentsmust meet
exactly. In additionto estimatesofp-ossibletrendsin the populationsandmodel
goodness-of-fitstatistics,adjustedR: (Rawlings1988)valuesandthe analogfor nonlinear models(proportion ofvarianceexplained:model SS/ total SSadjustedfor number
of parameters)which allow valid goodness-of-fitcomparisonsamongregressionrnodels
havingdifferentnumbersofpammeterswerc repo.ted.
196
ClutchViability Analysis
For LakeApopkadat4 the fit ofa non-linear
modelto alcsine-squareroot
transformedviability ratesregressedon elapsedtime was tested. This nonlinear
segmentedmodelincorporatedboth a quadetic anda linearresponseto test for possiblg
increasingtrendsduringrccentyears. The quadraticportion ofthe modelwas specified
first dueto the relativeamountofdata (yearsofsurvey) beforeandafter the lowest
measuredviability rate (the quadraticsegmentrequiredthe estimationofan additional
parameter).We allowedthe modelestimationprogram(ProcNLIN, SASInstitutg Inc.
1988)to choosethe point wherethe two segmentsmet by imposinga continuity
restrictionon the model- We specifledthat the quadraticandlinear segmentsmust meet
e)<actly.Additionally,we testedthe fit ofan identicalmodelfor the prcportion of
clutcheson Lake Apopkawhich producedrc hatchlings.
RESULTS
Clutchviability andClutchCharacteristics
During the summenof 1994and 1995,109alligatornestsfrom lakesApopka
andWoodrutrwere collectedfor incubationandother studiesandtransportedto the
centralincubationfacility in Gainesville(Table l). Clutch viability differedbetweenlakes
(P<0.0001;df- 103),butnotbetween
yeaxs
(P = 0.19 df=103;Tablel). Ir additioq
a diference was found in the numberofhatcblingsproduc€dper nestbetweenlakes
ApopkaandWoodruff (P < 0.001;df= 103;Tablel).
In pastyears,it was notedthat a significantportion ofhatchlingsproducedfrom
Lake Apopka's nestsemergedfom only a few clutches*ith manyclutchesproducing
no hatchlings(Woodwardet al. 1993iMassor 1995). However,during 1994and 1995,
lessthan 20% ofApopka clutchesproducedno hatchlings.In additioq Percivala al.
(1992) observedthat a largeproportionoflake Apopka's hatcblingsdid not survivethe
first week post-hatch.Very little (<l70) post-hatchmortality ocaured in 1994ard
1995. In general,eggmortality followed that observedby Masson(1995). Most
mortality occured pre-eggdepositionor in earlyincubationwith the nextlargest
proportion of mortality occuningvery latein incubation.
Clutch sizewas significantlyhigheron Lake Apopka (P = 0.006;df= 103;Table
l), but no diferencewasfoundbetweenyea$ (P = 0.22;df= 103;Tablel). However,
therewas no diferencebetweenthe two lakesin clutchweight (P = 0.37; df= 103;
Table l), indicatingthat meaneggweight on Lake ApopkawaslessthanLake
woodrufl Mean clutchweight was rot differentbetweenthe 2 years,1994and 1995(P
= 0.90:df= 103).
PopulationTrends
Count densitiesof subadults,juveniles,andthe total populationof animals
increased@ < 0.01) with decreasingwater levelson both Lake Apopka andLake
woodrufl Therefore,water levelwasincludedasan adjustmentcovatiatein both
models(WoodwardandMoorc 1990). Trendsor Lake Apopkawere investigatedftom
1980-1995
and1981-1995
on LakeWoodruff OnLakeApopka,forjuvenilesandthe
197
total population,the nonlinearsegmented
modelwaschosenover the linear regression
goodness
modeldue-to
of fit (for linearmodel:R'"dj< 0.18;P > 0.24;for nor inear
-R'"6;
> 0.78,P < 0.01). Thetotal populationdecreased
model:
apprcimatelyg406
from 1980to 1989thenincreased
approimately160%through1995@ < 0.01;-R':"6;=
0.87;Table2). Juveniles
decreased
by almost95%through1989thenincreased
by
<
48ulo overthe ne^16years(P 0 01 ^R2.d= 0.781Table2; Fig. 1). No trendin either
subadultor adult animalswasfound over the studyperiod(P > 0.70;R'zdj< 0.01;Table
2).
On Lake Woodru8 an increasingtrend of8.l0Z per yearwasdetectedover the
<30cm (P=0.001;R1a;=0.61;Table2).
studyperiodfor animals
(30-t2l
Juveniles
cm)inqeasedby 10.8%peryear(P = 0.001;*,a1= 0.72;Tzble2; Fig.2). Similarly,
subadult-arimals(122-182cm) increasedby 8.6% per yearthroughthe present@ =
0.001;R'"0,= 9.63,lable 2). A trendof 3.302peryearwasdetected
inthe adult
= 0.35;Table2).
populationoverthe studyperiod@ = 0.003;R'z"dj
Clutchviability trendson Lake Apopkawere similarto thoseresultsfor the
smallersizeclassesdetectedutilizing night-light surveys.A decreasein clutch viability
ofapproximately
80%from 1983to 1988andanincrease
ofover 400%through1995
=
wasdetected(P 0.05;-R'z.d;= 0.82;Fig.3).
A dedeasingtrend in the proportion of nestsfiom Lake Apopkawhich produced
no hatchlings
alsowasdetected
(P = 0.06;-R'dj = 0.78;Fig. 4). Theproportionof
nestsv/hichproducedno hatchlingsincreasedby about200%throughthe 1988nesting
seasonthendecreased
by 73% throughthe present(Fig. 4).
DISCUSSION
Lake Apopka's alligatorpopulationhasinoeasedsince1989after decliningfrom
1980-1989.This coinaideswith a similar declineandrisein clutchviability ntes. Will
this rise translateinto a real long-termrecoveryof alligatorpopulationson the lake?
One canassumethat the adult animalspresenttoday will eventuallystopproduction
through senescenae
or mortality. Someofthejuveniles prcsenton the lake today will be
recruitedinto the adult population. Ifthosejuveniles surviveat a sufficientlyhign rare,
€nterthe adult breedingpopulation,andproduceoffspring the populationmaybe able
to recovertoward the limits of its modem-dayhabitat. However,if observedabnormal
endocrinefunction andhormonalconcentrationshavealteredthe reproductive
capabilitiesofthose juveniles(assuggestedin Rice andPercivalI 996), anothe.
reductionin the populationcould occur. Obviously,only throughftrther monitoring of
the Lake Apopka populationcar this h'?othesisofrecovery be fully evaluated.
At tiis point thereis certair y ampleevidenceofsome recoveryon Lake Apopka.
Juvenilepopulationshaveincreaseddramaticallyin the last few years. However, certain
questionsarisewith datageneratedthough night-lightsurveyssuchasindependence
of
replicatecounts,numeroussourcesofcount vadatiorLandindependence
ofsightmg
probabilitiesamongthe young animals(which mayremainin pods). Whencoupledwith
the equally&amatic risein clutchviability rates,an inqeasein thejuvenile population
hasceiainly occurred. Further,the incleaseinjuvenilesdetectedduringnight-light
suweysbeganin the samplingperiodimmediatelyfollowing the observedincreasein
198
clutch viability.
An increasein subadultanimalshasnot yet occurred. Presumably,in the next
few yea$, the increasednumbersofjuvenile alligatorsshouldbeginto grow into this
segmentofthe populationifsurvival andgroMh ratesare sufficient. Thesecohorts
shouldbe monitoredboth throughthe subadultsize-classes
andinto the adult classto
population
pre-1980
recovery
to
levelsor a secondarycrash
monitor eithera
ofthe total
dueto reproductivefailure. Thereexistsa rareopportunityto observea d'.namically
changingwild population.
Clutch viability rateson Lake Apopka are still well belowthosefound on Lake
Woodruff La.keApopka alsoproducesfewer hatct ingsper nestthanLake Woodruff
eventhoughLake Apopka's alligatorslay moreeggs. However,Lake Apopka's clutch
viability ratesfor the last two yearsare comparableto thosefound in other areasofthe
state(Masson1995). It is unclearwhetherthe dilferencesin clutchviability between
lakesWoodruf andApopka is duein part to nutdtional,environmental,or contaminant
level diferencesarnong areas.Lake Woodruffis lesseutrophicandhaslessagricultural
efluents than other areas.Lake Apopkahada myriadof contaminantioputsincluding
muck farmson the rorthern shorewhich requirebackpudpingwater into the lake, citrus
orchardson the westemshore(now largelydefunct),andtrcatedmunicipalwastesi:om
the south. Futhe., Lake Apopka sufferedthe run-offfrom a largechemicalspill in the
early 1980'sandremainsan EPA SuperFundSite.
Alligator clutch sizeswere larger andmeanegg sizesmalleron Lake Apopka
than on Lake Woodruff Smallereggsareknoun to producesmallerhatchlings(Webb
et al. 1987;DeemingandFerguson1989;DeemingandFerguson1990),andhatcl ing
sizemay affect surviml probabilities.At this point, thereis no evidencethat the increase
ofjuveniles on Lake Apopka is beinghamperedby low survivalofyoung. Hovr'ever,if
the probabilitythat an increasewill occur in the subadult
survivalis in fact decreased,
and adult populationswill be lessened.Agair! this is fufiher causefor continued
monitoringofthe Lake Apopkapopulation.
Anothe. causefor optimismin the caseofthe Lake Apopkaalligatoris the
decreasein the proportion of clutchesthat fail completely.Until recently,most
hatchlingsthat emergedfrom Lake Apopkaalligatoreggsdid so fiom a very few rests
(Woodwardet al. 1993). A largepfoportion ofnests (ashigh as757o)produc.edno
hatcl ings. This total reproductivefailue ofmany nestingadult fernaleswhetherdue to
envi.onmentalcontaminantsdircctly or through someindirect (hormonal), demographic,
or environmentalcausecertainlyaontdbutedto the crashin juvenile populationson the
lake. In this study,a substantialdeqeasein total reproductivefailurc lvasfound. Most
nestsQ80oZ)producehatchliDgs.
Many hlpotheseshavebeenofered for the crashin alligatorpopulationsand
clutch viability on Lake Apopka. The most publicity (andresearch
continueddepressed
etrort) hasbeengivento environmentalconlamimnteffects(seeRice andPercival
1996). However,it is certainthat other demographicandenvironmental(habitat
changesandnutrition) are at leastpartiallyresponsible.
Lake Apopka's wildlife populationshavebeencontinuallyinfluencedby
exploitationofother lake systemresourcesthroughthe influx ofenvironmental
199
contaminants,nutrients,andthe lossofhabitat. However,evidencenow existsthat the
efects ofthis exploitationmay not persistindefinitely. Recoveryofthe Lake Apopka
a.lligatorpopulationis not a ce.taintyat thisjuncture, but the future doeshold promise.
LTTERATURE CITED
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populationsin Louisiana. Proc.Annu. Conf Southeast.Assoc.GameandFish
Comm.20:105-112.
Deeming,C. andM. W. J. Ferguson-1989.Effectsofincubation temperatureon growth
anddevelopment
ofembryosof Alligator uississiryienti.t. Joumalof Comparative
Physiology
B 159:183-193.
Deeming,C. aodM. W. J. Ferguson.1990. Mo.phometricanalysisofembryonic
developmentin Alligator mississippiensis,
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JoumalFood. London 221: 419-439
Ferguso4M. W. J. 1985.Reproductivebiology and embryologrofthe crocodilians.
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Reptilia. J. Wiley and Sons,New York.
Heinz, G., H. F. Percival,M. L. Jennings.1991.Contaminantsin Americanalligator eggs
from Lake Apopka,Lake Griffin, andLake Okeechobee,
Flodda. Environ. Monit.
Assess.
16:277-285.
Hines,T. C. andA. R. Woodward.1980.Nuisanceallieator control in Florida. Wildl.
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Jennings,M. L., H. F. Percival,andA. R. Woodward.1988. E%luation of alligator
hatchlingandegg removalfrom threeFloridalakes. Proc. Annu. Conf Soutireasr.
Assoc.Fish andWildl. Agencies42: 283-294.
Massoq G. R. 1995.Environmentalinfluenceson reproductivepotential,clutchviability
andembryonicmortality ofthe Americanalligatorin Florida.phD Dissertation.Univ.
Fl., Gainesville.
123pp.
Murphy, T. M. 1977.Distributior\ movement,andpopulationd]'namicsofthe Amencan
alligatorin a thermallyalteredreservoir.M.S. Thesis.Univ. Ga.,Athens.64 pp.
Peraival,H. F., G. R. Masson,andK. G. Rice. 1992.Variation in clutchviability among
sevenAmericanalligatorpopulationsin Florida.Mmeo report. FL Coop. Fish and
WildlifeResearch
Unit.UniversityofFL. Gainesville,
FL 32611.48 pp.
Rawlings,J. O. 1988. Applied regressionanalysis.Wadsworth Inc., Belrnont,Calif