Translation Series No. 1707

T1
FISHERIES RESEARCH BOARD OF CANADA
• Translation Series No. 1707
Biological basis for a rational commercia l .
fishing of gbbiidae in the ..Azov Sea (from "Biological .
foundations of the fishing industry and regulations
of marine fisheries") .
•by A. N. Smirnov
Original title: Biologicheskoye obOsnovaniye ratsionarnogo
promysla bychkov v Azovskom more (mBiologicheskie
• oshovy.rybnogo khozyaistva j regchlirovanie •
morskogo rybolovstva")
From:
•
•
Trudy Vsesoyuznogo Nauchno-Issledovatel-'skogo Institùta
Morskogo Rybnogo Khozyaistva Okeanografii (VNIRO)
• (proceedings of the All- Union .Research Institute of
Marine SUsheries n and Oceanography). Publ..by: Pishçhevaya
Promyshlennost, Moscow, 71. (2) : 37-50, 1970
.
Translated by the Translation Bureau( MI.)
•
Foreign Languages Division
Department of the Secretary of State of Canada
Fisheries lResearch Board of Canada,
Halifax Laboratory, Halifax, N. S.
Marine Ecology Laboratory, Dartmouth,
Biological Station, Nanaimoi B. C.
1971
-
31 pages - typescript
/76 /
SECRÉTARIAT D'ÉTAT
BUREAU DES TRADUCTIONS
DEF'ARTIENT O THE SECRETARY OF STATE
" TBANSLATIO,N;BUREAU
FOREIGN LANGUAGES
DIVISION
TRANSLATÈD FROM - TRADUCTION DE
.
DIVISION DES LANGUES
ÉTRANGÈRES
CANADA
INTÔ -•EN
English
Russian
AUTHOR - AUTEUR
A.N. Smirnov
TITLE IN ENGLISH - TITRE ANGLAIS
uogical basis for a rational commercial fishing of gobiidae in the Azov Sea.
•
Title in foreign language (transliterate foreign charactera)
,
iogicheskoye obosnovaniye ratsionallnogo promysla bychkov v Azovskon more.
R..F5RENCE IN FOREIGN 17 ANGUAGE (NAME. OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE FOREIGN CHAeACTERS.
REFERENCE EN LANGUE ETRANGERE (NOM DU LIVRE OU PUBLICATION)„ AU COMPLET. TRANSCRIRE EN CARACTERES PHONÉTIQUES.
isesoyuenogo nauchno isaledocatchiskogo instituta morskogo rybnogo khoeyaystva
dy
. .
anografii (VNIRU)
REFERENCE IN ENGI_ISH - RÉFÉRENCE EN ANGLAIS
Scientific-ReSearch Institute of Marine Fisheries and Oceanography (VNIRO)
• PAGE NUMBERS IN ORIGINAL
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. L'ORIGINAL
PUBL ISH ER - ÉDITEUR
DATE OF PUBLICATION
DATE DE PUBLICATION
VOLUME
ANNEE
PLACE OF PUBLICATION
LIEU DE PUBLICATION
ISSUE NO.
NUMÉRO
37 - 50'
NUMBER OF TYPED PAGES
NOMBRE DE PAGES .
DACTYLOGRAPHCÉES
1970
REQUESTING DEPARTMENT
MIN IST ERE•CLIENT
:51
LX.X1
fisheries & Forcer,'
TRANSLATION BUREAU NO.
NOTRE DOSSIER N°
0894
TRANSLATOR (INITIALS)
TRADUCTEUR (INITIALES)
M.I.
•
Fisheries Research Board, Halifaxl_N.S.
BRANCH OR DIVISION
DIRECTION OU DIVISION
PERSON
IR EQUESTING
DEMANDE PAR .
udense & Dr. U.U. Acknan
Dr.
jlalifax Laboratory
YOUR NUMBER
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APR 3 0 1971
ONL'UVITO DRAFT
•
Conty
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for information
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tos-200.10.0 (MEV. Veil,'
February_e_1271
REVISÉE
Infornmiion seu!cment
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TRANSLATION BUREAU
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.
Fisheries & Forestry
.
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'
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LANGUAGE .
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M.I.
Russian
0894
VOLUME Mil
DATE
APR 3 0 1911
.erepared by the Ail-Union Scientific- Research institute of Marine Fisheries
and Oceanography (VNIRO)
1970
Universal Decimal Classification
(UDK) 69..39 46k-54)
ellue
BIOLUUICAL BASIS'FOR A RATIONAL COMKERCIAL FISHING. LW GQ,
C;b:AFT -MANUA HON
Az,uy SA. (1)
O r ly for information
TRADUCTION NON REVISÉE
InfonnMion soulernent
Uobiidae are very plentiful in . the Azov Sea. The yearly catch during
A.N. Smirnov
the period 1930-1954 varied from 100 to 390 thousand centners(2). But, at.
certain timers during that same'period (1930, 19 $ 7, 1950). , it.dropped down to
44-62 thousand centners.
With the introduction
or mechanized drag nets in 1954,
the size of the
catch underwent a noticeable increase. During a decade (1955-1964), the yearli
catch fluctuated between 330 and 916 thousand centnere but, on the average,
The viewe expressed by A.N. Smirnov regarding the biological control of goby
fishing in the Asov.Sea do not always meet those Of V.A. Koetyuchenko (see
next article in the present series)*
Although the editorial board agrees with the views of A.N. Smirnov and other
researchers who advance very valid reasons against the fishing of gobiidae
during spring, it is hoped that the publication of the articles by the abovemmntioned authors willt attract the attention of other scientists towards this
question and that th eywill express their opinions after studying newly
•
available materials. .
:(2)
One centner equals 100 kilogrammes (USSR).
2,
amounted to 600 thousand centners. About zoo veseels equipped with .
mechanized drag nets are engaged in goby fishing as well as other vessels
which use manually operated or semi-mechanized drag nete.
Concentrations of gobiidae are'to be found mainly in the northern
part of the sea in the . areas of Belosarayikiy Bay, Elenina spit, Zhelesinskaya
shoal, Berdyanekiy bay, Obitochnoya spit and along the entire coastline
from Yrimorskaya Settlement to Biryuchiy Island. These are*e conotitute
the main grounds for goby fishing.
.
Observations show that young fish of various valuable epergnes which
•
include pike-perch, Azov roach, herring and sturgeons are taken together
with gobiidae t In abundant years, the take of these young fish reaches
.
substantial proportions. .Uoby fishing ha s a particularly damaging effect
on the reserves of pike-perch.
Thus, during the autumn fishing season of
1963, which was a year of abundance, Sobrdrage netted about 4 million
young pike-perch.
Without considering natural mortality rates, this .
constitutes a loss of 50 theusand centners of commercial fish.
In abundant years, goby drags also net large quantities of young
•
Azov roach, Thus, durinithe spring of 1965, one million three hundred
thousanà young fish were caught. In certain fishing areas (squares) the
catch of young fish reached Z,550 epecimens per drag net sweep,
.Mechanized goby drags also net young sturgeon». In certain areas,
the proportion reaches substantial levels. In August, 1964, for instance,
62 young sturgeons were caught in three sweepà of the drag net
be
the
commercial fishing veeeel SchS-1159 in the area of Obitochnaya epit.
.
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. Azov
5. Kamyshevat skaya s ettlement
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9. Te /711k
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•
4
Xr
38"
6
PliC.
1. Pakoilbi npoubmea 6bitixa:
1964 r.;
—» learn-re—curse> 1934 r.
ig. 1. - Gobrlishing araaea - spring 1964. b August-Sept.eraber 1964.
.
5.
In 25 sweeps this vessel netted 188 yOung sturgeons and sorriugas.
sweep netted from 4
Each
(49)
to 43 young sturgeons.. On 19 August, 1965, the vessel •
SChS-1232, operating in the area of Berdyansk, netted 52 young and 15 mature
sturgeons in two sweepe of the drag.
.
.
As a result of these circumstances, we are faèed with the tek of
deternining all the factors affecting the netting of young fish of valuable
species during fishing for gobiidae and implementing measures to control
the situation.
The biology and population dynamics of the main commerCialtype of
the round goby have been studied in sufficient depth by V.A. Kostyuchenko
(1961). 'The biology of the reproduction of -Azov gobiidae has been studied
in detail by
(Le. Trifônov
(1955) and V.K. Rashcheperin (1962, 1963 and 19610.
The rational fishing of gobiidae.and overall control of fishing operations
are outstanding problème which have not been the subject of much research.
Fishing for gobiidae was undertaken without consideration for the particular
features of their lives or for basic principles-governing an efficient
fisheries conservation programme. Younger age groupe of.gobiidae were
allowed tole harvested in substantial quantities and spawning grounds were
not protected. In addition, substantial nuMbers of.young
ash of valuable
species, such as pike-perch, sturgeone etc., were also netted
.
Such practices result in a decline of the fish population, ,a decrease .
of the biological productivity of the sea and an undesirable change in the
structure of commercial species of fish.
•
6.
METHOD OP RESEARCH
Studies regarding the netting of young fish of valuable species
•
and the sise and weight composition of the goby catch by mechanised drags
out
'
were carried/directly aboard fishing veseele from 1963 to October, 1965.
Adult and young pike-perch, Azov roach, herring and other species, were
removed from each • take in a drag net and counted. If large quantities
Were involved, an averaging method was used by taking a sample amount of
.
gobiidae (30 kg).
Besides recording the numbers of young fish of valuable •pecies, a
biological analysis of gobiidae (in batches of z00 specimens) was made two
or three times a day to determine the length of the body, sex and overall
weight.
A total amount of 150 thousand specimens of gobiidae were analysed.
Senior tethnicians of the Azov Scientific4tesearch Fisheries.Institute
(AzN11h£11), V.A. fodkolzin, A.A. Nikityuk, V.V. Ukraintsev, (.S, Alferov • .
and.A.N. Kopshiter 8 participated in the collection of data aboard fishing
vessels.
•
TAXE :OF YOUNG FISH Of VALUABLE SYECIES BY GOBI DRAG NETS
•
Goby fishing took place from 1 April to 1May, that is, before the
spawning season. If spring was late to come, fishing operations were
extended beyond 1 May.
Fiehing grounds were located.in the coastal sone
of the Belosarayskaya and Berdyanskiy baya, and along the cdastline from
ObitoChnoya to Biryuchiy Island.
Our . studiee t196j 1965) revealed that fishing gobiidae with mechanised
-
drag nets
itS
less effective in spring than in autumn.
The average catch of
gobiidae per sweep of the drag net amounts to 1.4 centners in spring and 4.5
7
centnere in autumn.
.
In spring, gobiidae stay apart and the majority of
•
.catches vary from 1 to 3 cehtners.. In autumn, gôbiidae for denser
concentrations and the catch per sweep of the drag net often reaches 25-35
.
centners.
It must be noted that if an excessively large nuàber of vessels
is involved in fishing operations, the amount of fish netted by mechanised
drags decreases.- This may be seen from the following facto.
erior to
massive fishing operations, the catch of searching vessels in 1964 amounted
to an average of 8 centnere of gobiidae per sweep of the drag net. With
(41)
the appearance of. large fishing fleets, the 'average daily catch became two
times emaller..
And, conversely, a decrease in the number.otveasels
(from 2010 to 100 in October), resulted in catches which were 1.5 times
greater.
The take of young pike-perch by goby drag nets during the sprint
prior to 30 April
1964 in the
•
Belosarayskiy Bay amounted to an average of
1.4 specimens per sweep while 2;3 specimeno were taken in the ara of
Obitochnaya spit and in the Berdyanskiy Bay.
The mejority of sweeps
produced from 1 to 3 youngl>ike-perch specimens.
.
Certain individual sweeps
yielded as many as 34J - 96 epecimens. The number of young pike-perch per
centner of gobiidaes landed in the Belosarayskiy Ba'Y amounted to one
specimen and to two specimens in the area of the Obitochnaya s it. An of
the beginning of
(table 1). .
May, the take of
young fish increaeed noticeablY
Take of young• fish of valuable species by Crag nets during sprieg 1964 - 1965
Young ,
• ishing
tree
.
Timm
•• of ,
year.
Number
of
sweeps
Liebytake,
centnera
pikeperch
fish
caught,
numbers
Azov roach
Average
per
sweep
Average
per
sweep
sturgeons
Average
per
sweep
Average'
sweep
1964
3erdyanagy Bay
Single
specimens
lelosarayskiy Bay
1965
1.1'th-eastern
)art of the sea.
kirdyanskiy Bay
tad ObitochnaYa
spit
4ast1ine from
irimorsey
• 4il1ement to
liryuchie
Mland -
0,2-
9.
Until the end of April 1964 there were no young Azov roach netted
by goby drags except for a few individual specimens caught in the Belosarayigy
Bay. In July, substantial numébers of young roach were present in the
Berdyanskiy Bay and in the are* of the Obitochnaya apit.
.
•
This was reflected
in the catch. In 1964 and 1965, - young sturgeons were netted by goy drags
on rarer occasion in spring than in autumn as these fish usually keep to .
deep watere during that season.
In April, 1964, forty-tue specimens were
netted during 280 sweepe in the north-eastern pert of the sea; in April •
1965 - four specimens during
12 4
sweeps (2 Specimens during 14k sweeps in
the Berdyanakiy 141).
Take of young fish of valuable epeeist during autumn. Data relative .
the. take of young pike-perch, roach and sturgeons by mechanised gOby .
drag nets . during the autunn in the years 1963-1965 is shown attable
to
2.
Herring was caught in inSignificant numbers and, therefore, data has been
omdtted.
The size of young pike-perch, roach and sturgeons netted is
shown at figure
k.
'
•,
•
-
The sise of the take of young fish depends on numbers preeent.
The •
year 1963 was particularlY productive for many species of fish - pike-perch,*
bream, sturgeons,.rOach„ herring etc. - The years 1564 and 1965 were lus
•
abundt.
Take of young fish of valuable sPecieti by mechanized drag nets during the autumn fishing season of the
years 1963 - 1965 in the northernpart of the sea.
(0bitochnaya spit - Kamyshevatikays spit)
Young fish taken,
Time
Number
of
Year .
of
sweeps
Take of
uobiidae,
centners
-
numbers
Average
take
per
"Weer)/
Azov
pike-perch
Total
centners
Average
per sweep
Total
roach
sturgeons
Average
per sweep
Average per 100
sweeps
,
..,
1963
4ugust
September
74
191
51
dtteber
4, 6
4,6
44 0.
34z
858
20 5
4' 544
17250
48 -
34,0
91,0
1,0
0
0
0
1
5
0
0
0
ù
'
1964
,
/tree
-•
455
5426
-2125
6,2
4,7
301
1697
.6,7
• 880
September
gletOber
_
2360
2116
408 '
.48
11540
4,7
74
1,4
1
7,6
0,
,
-
6
18
7
.
1965
_
,
Lugust
lepteMber
'
557
390
1
4188
2070
• 7,5
5,3
-2152
. 2120
3,9
506
15094
673
27
1,7
24
10
u
.
in August, when large ;lumbers of youiig pike-perch were still located .
.in the Taganrogskiy Bay and in coastal waters of the eastern part of the
sea,.the average take by goby drag nets constituted j4 specimens per sweep
or 7.4 specimens per centner of landed gobiidae.
In the first half of
-
September, due to increased nuMbers of young pike-perch emerging from the
Taganrogskiy Bay and'spreading in the sea, the take increased threefold
and amounted to an average of 106 specimens per sweep of the drag or k2
specimens per centner of landed gobiidae.
In the areas of the Belosarayskiy
Bay and elenina spit, the take of young pike-perch varied from 2.40 to 1,000
specimens per sweep.
•
By the end of September when gobiidee left the coastal: zone for deep
waters, the take of pike-perch decreased to LJZ specimens per sweep and
fluctuated between 11 and 58.
in October, the major mass ofsobiidee
•
remained in the central regions of the northern part of the see. &s ea
result of which, the take of young pike-perch dropped to one specimen per
sweep (table J).
•
Nu
Table
•
ers of young pike-perch taken in mechanised goby drag nets
(Average per sweep)
Time of year
•
August •
196 >
-1964 .
1965
j4
j x 0.
...1,9
First half of September
106
Second half of September
j2
October
1,0
9,1 .
8,4
1,8
4,2
1,4
1,5
)
32.
«,It is important to not that in the fall the aroas. of young pike.perch concentration are tied to regional concentrations of gobiidae where
they feed. In Uctober„ the take of young pike-perch is several times
lower.
'
This ie due to the movement of gobiidae from coastal waters to
•
• '
. deeper areas of the sea.' .That is why, fishing for gobiidae should be
intensified when the take of younglish of valuable epeciee drops sharply.
In years'when pike-perch are abundant and young fish are found in large
numbersin goby drag nets, fishing for gobiidae should be discontined in
areas where the young fish are concentrated.
Uobiidae should not be fished at the'Zheleminskaya shoal at any
time of the yegr as it is an area where not only young pike-perch concentrate
but also sturgeons.
The amount of young reach taken in goby drag nets *lao
depn
on the abundance of these fish. Ueually„ during commercial fishing .
operations,. two year old roaches are netted which measure from 10 to 15
centimeters (young of the year easily slip . through the mesh of the net).
In 1963, very few young roaches were found in goby drag net catches which
was due to a low-year-class in the . yeare 1961 and 196.
i.
. •
Due to strong-year classes in 1963 and 1964e.young roach spread out
widely throughout the sea aneUin 1964 and particularly 1965, the take of
these fish in drag nets was noticeable larger.
Hoach concentrate mostly in
the areas of the Belosarayskiy and
Berdyanskiy Bays and the Derdyanskaya
spit and, to a lesser extent, in areas
far removed from the coast.
In August, 1964, the . take of
young roach per - sweep.of a drag net
15
averaged 7.6 to 8..3 specimens.
zo
.1965, sixteen speciàene were taken in
10
the Berdyanskiy Pay and in the area
\
5
12 16
of the Obitochnaya spit, 60 specimens
J1
IS 28
et
a
,
in the area of the Berdyanskaya !pit.
40
In certain sWeeps the take reached 15002500 . epecimene.
It`
X
2
Knowing that young roach
10
keep to coastal . areas'of the sea, the
18 20 cev
10
d
b
.
take of these fish may be avoided by
fishing for gobiidae further - away front .:
the coast.
No natural laws related to
abundancy were established-in respect
of young sturgeons netted by goby
'drags. Three years of observations
.
revealed that, on the average, the
Fig.Z. Length of young fish netted by
goby drag • nets, : a - pike-perch:
1 - August 1963; .z-iugust • 1964;
specimens per 100 sweeps (see table z). b - roach: 1 - Belosarayskie bay:
Z Qbitochnaya spit: c - sturgeon; .
1 - Obitochnaya spit.
take of young sturgeons amounted to 4
•
-
•
During the fattening period, eoung sturgeons gather inshoals and the
fishing for gobiidae Should be.discontinued when the latter are found.
Sturgeons which do get netted should be released immediately. With
sensible fishing practices by experienced fishermen, the conservation of
young sturgeon type fish and roach should not preeent any difficulties.
/oung pike-poi:eh present a greater problem beeause of their lower rate
In cases when young pike-perch are taken in large quantities,
of survival.
fishing for gobiidae ehould also be discontinued in order to preserve the
species.
.
.
-
Tables 4 and 5 show the damage caused to fisheries through fiehing
out young fishof commercial value by goby drag nets during the autumn in •
the yeare 196j-1965.
•
In autumn 1963, the takeof young pike-perch resulted in loonies
amounting to 64 of the total . coet of - gobiidae.
Should young sturgeone
and roach be included, these losses would be even higher. During the fall
of 1965, the losses in . valuable fish constituted 52% of the coot of the .
goby catch. 'Broken down by species, these losses'amount to:
z.J% for
pike-perch, u.4% for roach and 49% for sturgeons. Delaying the tinkling'
of gobiidae from 16 August to 16 September we'd Substantially decrease •
the. losses incurred through the take of young fish of commercial value.
iL&J
roaca aaà sturgeons in the spring éf 1965..
uLko.J.Ja
Item
pike-perch
Jac)
'Landed in spring, thousand specimend.
'
Roach
Sturgeon
1>up
1,05
1+,1 - -
,
Average take of young fish per centner of gobiidae.
5,5
18,6
0,15
Average .weight in commercial age,
1,2
01 15
15,0
4,6
2,0
0,157
18° •
50
180
kg
Losses of commercial fish, thousand centners.
thousand roubles.
Losses,
1110M:
•
"•
-
6;757
1
.
410
The goby catch during the first six months of 1965-by all fishing concerns amounted to 70 thousand'centners, • The
cost-of one centner.of fish amounted to: gobiidae - 10 roubles, 50 kopelaq pike-perch - 39 roubles; roach.- 25 rodbliSy
sturgeons - 115 roubles.
Table 1.
Losses caused to the fishing industry through the netting of young pike-perch-by goby drags during the fall fishing-season.
-
• .
'
r.
Gony,Cetth,
thousand
'
.
centners. .
•
.
•
Take of young -.
centners of
gobiidae,
number of
specimens.
•
,
•
Losses of
commercial pike-.
perch with an
pike-perch
landed.
•
average weight
'
ge 1.2 kg,
Thousand centnere.
Financial
losses,
thousand
Total cost
_
ef goby catch,
thousand
roubles.
roubles.
'
.
- 267
1963
Total
- nueber of
pike.perch per
,
14,5 -
.
3780
1670
45,4 '
•
2800
1965
511
0,5
•
256
3,1
430
0,5
•
230
2,8
,
•
121
5365
106
4515
.
.'
eALITATIVE, COM.e0S1TION. OF CUMntiCIAL LieBY CATCHES
The reproduction of the round goby.takes place over an extended
time period.
If siring comes early, then it approaches the coastal sone
in mid April. In cold spring weather, this takes place at the end of
April or in early May.
June.
.It
The height of the spawning period is in May
or
decreases in July and ends in August. Due to a cold and long
lasting spring season in
1965,
the spawning period continued into
September; Due to an extended spawning periodi the October catches by
means of the beamtrawl contained young gobiidae of 20 mm in length and
. OVer
•
,
.
On completionof spawning, the goby. usually moves from coastal
areas-into the depth of the sea and gathers at feeding grounds. In the
fall of the - years 196 $, 1964 and 1965, the main maes-of gobiidae concentrated
in the northern part of the sea practically to the line extending from the
Zhelezinskaya shoal to Biryuchiy Island. Ihat is where coimercial fishing
.
took place..
Commercial fishing . for gobiidae mainly involves the netting of two
to three year old fish in the spring and the same in autumn (14 , 24. ).
The relationship.of different age greupe in the catch . depends on
strength of the year class. If a particular generation of gobiidae was
numerous, then it will predominate in catches of the following year.
If
the contrary is true, then the percentage of two year old, fish in autuin
catches of the following year will decrease and the-number of three years
old will rise.
•
(45)
17.
re or
I
t
1
•
%
or
A.
sa
10
5
o
o
70
90
00
IX 150 f70 MM
a
70
flO ISO 450 170 ex
2
o
70 90 00 100 /50 170 MA
d
ng.
a
j. .Length of the round goby taken by mechanized drag nets.
.
in spring 1964 in the north-eastern part of the sea (average length of males - 129 mm;
.. females - 109 mm); b - in epring 1964 in the Berdyansay bay (average length of males
• 126 ang females - 102 mm); C - in epring 1965 in the north-eastern part of the sea
. (average length of males - 98 mm; females - 93 mm); d - in epring 1965 in the
BerdyanskiI bay (average length of males - 111 fin; females - 103 mre; e
.in
epring 1965 from the Coastline of Stepanovka Island to the Biryuchle Island (average
length of males - 1,34 mm; females - 109 mm);.1 - males; 2 - females
18.
The years-1,960, 1961, 1963 and 1964, were particularly abundant in
.the case of gobiidae.
Catches. during the period 1960.-1965 fluctuated
between 530 and 600 thousand centnert.
The le ss productive year of 196Z
resulted in lower catches of gobiidae in 1963 which dropped down to 330
•thousand•Centnera.
The sive of round goby in commercial catches depends on the nusiber
of different generationa in the school and on conditiona of'growth.
Differences in size also prevail in different areas of the aea (figure 3).
In order to determine the size, weight and aex composition of round
goby, a biological. study wis undertaken aboard veasela during spring and
autumn fishing seasons during the period 1963-1965 (figure 4.)
over 9u thousand specimens of eiidae were stndied.
In 1964,
In the spring and
autumn of 1965, 7,60(. and 4,500 . epecimens were analysedrespectively
(table 6).The difference in the size composition of gobiidae may be explained
by an Unequal rate of reproduction. The productive year of 1962 resulted
in an increased amount of two year.old gobiidae being netted in 1964. The
hi gh reproduction rate of gobiidae in 1965, in turn, resulted in a higher
number. of siail-fish. being netted in 1965. •
, Table à.
Length and weight of round gobiidae taken by commercial mechanized drag nets during the summer in the
years 1964
1965.
Weight,
Length,
g
Weight
g. .
Length,
.
Fercentage
Bath sexes
Female
Nee
Fishing
area
-
Length
4eight
SIMI.
undersize
up to 95 mu.
Spring 1964.
North-eastern part
, of the sea.
129
Spring
,
North-eastern part
ot the sea.
.....--.
Berdyanskiy Bay
North western
V
coastline
(StepanovkaBiryuchiy Island).
3,5
38
18,7
97
Z3
48,0
ke
106
30
31,0
34
i21
45
6,8
28
.102
51
Bercl,yaneldy Bay
116
39
34
1965.
98
' 98
V
.
lU
103
35
'
-
134
60
109
V
,
V
.
20.
The size of round gobidae taken commercially during the spring of
the years 196i - 1965 is shown at table 7.
The size of gobiidse in fall catches depends on the nunber of two
year old fish present.
•
In 196J and 1965, the average length of both males and
females was identical which was due to good reproduction in preceding yearn
(1962, 1964). _Eri 1964, catches contained larger specimens Of gobiidae,
products of the fertile 1 962 generation. Data attable
7 shows the growth
of the goby during the fall period.
Uraphs relative to the size composition
of the round goby (figure 5) show that
the latter tende to increase in sis.
fromAugstOcber.
The 'appearance of several peaks in the
graphs depends oh the number of
10
different generations in the • chool,
110
growth rate And the general and natural
WO
00
môrtality rates. Graphs with two and
80
three peaks usually refer to conditions
prevailing in August and SepteMber.
50
In
40
October, multiple peaks disappear •
70
0
because of the.rapid growth of two year
so
80 100 120 140 160 180 mi
old fish,.a slower growth of three year
old specimens and a high mortality rate
among older age groups.
Figure 4, Weight of the
round goby in relation to
its length.
• 21,
•
Data regarding t he size, composition shows that , from a, biological
viewpoint, it la more expedient to fish for goby as of the second half of
September.
'
.4y that time, email gobiidae reach a commercial size and improve
In quality. Besides, with the retreat of the
gobiidae from coastal areas
• into ,deeper waters, the takeu of young fish of valuable epecies decreaaes. •
• Sax composition of round-goby in commercial catches.
noted that the male
Earlier,we
goby grows faster than the female and that its average
length is 15 - 20 millimetres greater. Consequently, with an identical
commercial
/22.
Length (centimetres) of the round goby in commercial catches during autumn in the years1963 - 1965. :
1963
1965
1964 •
North-eastern part of the
sea
North-eastern part of the sea
Beràyanskiy spit and ObitOchisoleJli
Month
females
females' males,
females
males,
females
males
isam4.
umelipiJ
females
•
AUgust
10,9
9,5
10,0
11 ,9
10,5
11,3
11,5
10,1
September
11,0
-9,7
10,5
11,3
10,1.
10,6
11,5
10,0
October
12,0
10,1
11,3
12,7
11,3
11,6
12 ,7
11,3
. Continuation...of Table
11,6 . .
7,,L
1965
MIWIMP
North-eastern part of the
sea
Month
Neel;
August
10,8
September
11„U
October
•
females
males
males,
females
10,2
9,8
10,6
10,4
11,3
North-western part of the sea
Berdyanskiy spit and
.obitochnoya spit
.
•
females
meles,•
females
10,8
9,z
10,z
100
9,6
• 10,4
J2,5
10,4
males
11,8,
11,
•
females
males,
finales
11,0
11,7
9,3
10,7
'
'L
1
• -1 4
7.
21 r
21 -
li
II
CF
.
2
-
1
15-
I 'I
15
1
12
-
n --J700
11,1-126
Mr --10d
11/M — L57.
f2
9
5
1
3
3
50 W 100 /20
140 150 mi
50 60
POO CO
140
ISO poi
e
a
IS
50
80
100 te
(40 fro nil
6
Figure 5,
Length of the round goby in commercial catches taken in the
north-eastern Part of the sea in 1964.
a - from 1 to 15 August;
d - October.
1
females; k
males.
b
-
15 to .31 August;
c - September;
4.
size (95 mm) fer both males,and females, the sex composition in catches
determines the :luster of undersized gobiidae taken.
The greater the number •
of males in catches, the lesser there are of undersized gobiidae and vice. - versa. Thus, for instance, in the Berdyanskiy Bay dtu'ing the period August September, 1964, the proportions in the catches were as followsl
males
ee
0 ,0
ée
*0
00
••
00
ele!
•••
••
••
e•
••
••
'••
e•
90
f emelles
Undersized Males.
••
46-5e
.
Undersized females ..
16%
35%
à.
undersized specimenS of both sexes ..
ee
22%
• •
In tile areas of the Belosaraiskii Bai and the Elenina Spit the
catches during the same period reflected the following proportions:
Males ..
•41
••
undersized males.
••
.4.
••
••
e•
••
60%
e.
*a
ee ee ee edle
4%
••
••
undersized females •. is u, .„
total quantity of undersized fish of both sexes.
.
9,5%
Ail this must be taken into account when regulating commercial
fishing (table. 8).
Table 8.
Sex composition in commercial catches of gobiidae during the year 1.964 (in percentages)
North-eastern part of the $ea
(Berdyanskeya spit,
lÇaieshevatskaya spit.
Berdyanskiy area.
Time of observations.
ele3
females -
total
females
total
kb.
During the pre-spawning period (April - May) of 1964, the number
of males and females was equal at the spawning grounds of the Berdyanskiy
Bay.
At the height of spawning the number of males dropped to 42% and at
the end of the spawning (July), their numbers went down to
37%.
Only
males guarding the eggs deposited in nests remained. Beginning with
Auguat, the number of males in catches increased gradually. During the
first half of August, catches in the Berdyanskiy Bay ehowed a 39% male
content. During the second half of August this increased to 4D% and
reached 54% in September. By the end of autumn the number of males and
females gradually evens out.
The same was observed in 1965.
TUWARD A RATIONAL FISHING UF GOBILDAE
First of all there ie the , question of the expediency of fishing
gobiidae during the spring. N.A. Smdrnov and V.M. Nauiov (1964) noted that
spring goby fiehing taken place mainly at'spawning grounds in coastal waters. .
At the eame.tine,- commercial drag nets destroy large quantitiesof egg
•
deposited by gobiidae on the sea bottom and aleo net many young specimens
of pike-perch and roach. In the epring of 1965, the làss of valuable
species of fish-constituted 56% of the total value of the goby . oatch.
The
•
take of young . pike-perch per - centnerof gobiidae amâunted,on the average,
to 5.5 specimens while.the number netted per'sweep of the drag net equalled
7.7 specimens as compared to one allowed by fisheries regulations.
The take
of young roach amounted at that time to 18.6 specimens or twice as many
atit in autumn.
'
•
.
•
'417.
According•to data supplied by V.A. Koetyuchenko, theamount of two
year .Gad gobiidae taken in the nets cOnstituted 70-84.
It is a known •
fact,that the average weight of two year,old gobiidae taken in the spring -.
equal 25 grammes. In the course of four nonthe (in Septelber), their
weight doubles. 'Therefore, from eprirg through fall their number increase
as aMatter-of fact and the qgality of the commercial production improves.
The spring fishing for gobiidae by means. of mmchanised drag nets is
The epring catch in the years 1963-1965 .
lees effective than in the fall.
amobnted to merely 10-154 of the year round take.
The average take of
gobiidae per sweep of the net in spring amounted to 1.4 centners.
In
autumn, it had risen to 4.5 - 5.0 centners and, in 1965, it even rose to
6-7 centners which was 4 to 5 tires greater than the spring take. In the ,
springi gobiidae stay fairly well dispersed and catches of 1-3 centners
per.sweep prevail. In the fall, the gobiidae stay.at feeding grounds in .
denser-concentrations.
At that time, catches frequently reaoh 10-20 •
centners per sweep of the drag net and, in.certain cases, even amount
to j40-35 centners.
The quoted data shows that it is not expedient to fish for gobiidae •
in the spring. The discontinuation of pring fiehing for gobiidae will help
.to inorease.commercial reserves and produce better - quality fish in the fail.
What would be considered as an acceptable take of young pike-perch
and roach by mechanized drag nets? lesuming that 120 vessels equipped with
mmohanised drag nets will be engaged in goby fishing during the fall season
and each one will make an average of 10 sweeps per day, then in 40 - 50
fishing days one vesse l will make 400..500 sweeps and 120 veeiels - 48-60
thousand . sweeps.
At the average rate Of 4 young pike-perCh netted per sweep,
•
28
this will amountln 192-240.thounand apecimens or 2.4 - 2,8 thousand
Ceàtners of commercial pike-perch with an average weight of 1.2 kg for
the season.
we Consider that 400 thousand specimens of Young pike-perch is an
acceptable take during the fall fishing for gobiidae. This quantity will
not affect the commercial reservee of pike-perch. .in years when young
pike-perch are in abundance,as was the case in 196j, goby fishing should
be discontinued except in areas where these fish are present in small •
numbers (north-western part of the sea). •
young roach from being cauet by mechanised drag nets
• • To saféguerd
fishing
during th è fall/season'emmogmèdàdnmockkMdmggis Considerably °eider. Areas
,where young roach concentrate do not always coincide with those favoured
by gobiidae. The latter leave coastal waters for deeper areas of the ses
In cases when
duringfalwheyoungracslykeptohawrs.
young.roach.are netted in large numbers, vessels merely have to change their
.fishing areas by'sailing further awey from the coast: Studies have ehown
that, during the fall period, young roachConcentrate mostly in the
Belosarayskiy and Berdyanskiy bays as well as in theareas of the Elenina
and Berdyanskiy spit. Fiers, up to 1 - 2 thousand specimens are sometimes
netted in à single sweep.
Further out to sea from these areas where the
main concentrations of gobiidae are to be found, the
great.
take
of roach in not
•
•
If one considers that in average of 20 young roach are netted in a
single sweep of the drag net, then about 1.2 million specimens may be .
caught during the fall fishing season which represents not more than 1.5
thousand centners of mature fish. ' •
•
29
In the till of 1964, goby,drags rutted 850 thousand young roach.
In 1965,
the number decreeted to about 500 thousand. With the shift of gobiidae
froacciaetal areas to . deeper waters in the second half of September, only: of roach are found in the nets. .
•
indvualspecmn
lOung sturgeons are found in goby drag nets in ail ar as of the sea
and stand out from other fish by their high rate of survival. Therefore,.
they umr be easily returned to the 's«. Fishing for gobiidae should be •
pràhibited or undertaken elsewhere when large quantities of young turgeons
are present.
The number of young fish of valuable species that is netted depends
alSo on the deeign Of the fishing equipment.
The use of the modernised
drag net for goby fishing with a z.7 metres height between pocket and wing .
and 1.6.metres at the brails, as suggested by E.V. Shapunov (Azov-Black Sei .
Scientific Institute of Fisheries and Oceanography); instead of the
conventional drag net with a height of 4.5 metres between pocket ind
•
allows to haIve the take of young pike-perch withcut affecting the'
.
catch of gobiidae.
-
.
It must be noted in conclusion.that a discontinuation of goby fishing
in the epring r a reduction of the fall season as of 1 September), less
intensive fishing operations .(number of vessels involved), adherence to
are necessary
tithing regulations and the implementation of other measures/to prevent the fishing out of large quantities of young . fish of precious species and to
increase their reserves.
t■•,f-
•
•
..! • •
o
.
(
Spring fishing for gobiidae should be discontinued le fishing
operations take place mostly in coaetal waters at spawning grounds where
many young pike-perch and roach are caught in the drag nets especially in
abundant years.
•Fishing for gobiidae should start an of the second half of September,
that is, from the moment that large gobiidae separate thenmelves from
.
young fish and those of valuable species.
in order to improve the qualitative (age) composition of goby schools
and decrease the take of young fish of valuable species, goby fishing
ehould drop in intensity (number of fishing vessels) by 40 - 5(4:
It is recommended that a mechanized goby drag net of improved desigm
be used in order to.lower the take of young fish of valuable species.
ee
V.A. Kostyuchenko. Vosrast i temp rosta bychka-kruglyaks v Asovekom
more. Trudy AscheeIRO. Vyp. 19, 1961.
Age and growth rate of the round goby in the Asov
pelished by the Azov-Black Se a Scientific institut. of
•
Fisheries Ace Oceanography (AzcherMIRO), Issue 19, 1961.
.K.Sashcheperin. Usloviya i regUlltaty rasmnosheniys bychke-kruglysks
1961-1964 gg. Sb. annotatsiy AsNllftKhs sa 1962, 1963, 1964 88.
V.K. Eashcheperin.
the ;years 1961-1964.
Condition and results of round goby reproduction in
Collection of annotated works of the Azov Scientific-
Research Institute of Fisheries covering the years 1962, 1963, 1964.
A.N. •Sernov, V.M. Mauna«.
0 biologicheskikh obosnovanyakh regulirovaniya
rybolovstva v Azovskom more. "Nbnoye Khozyaystvo", 1964, No..
•
A.N. Smirnov e V.M. Naumov.
Biological basis for the control of
commercial fishing in the Asov Sea,
"Fisheries", No. :4, 1964.
G.e. Trifonov. Biologiya razmnosheniya asovskikh bychkov.
Trudy
.
Karadagskoy biologicheskoy stantsii. Vyp. 13, 1955.
Trifonov.
Biology of the reproduction of Azov gobiidae.
Yapere
published by the Karadagskaya biological station. Issue 13, 1955.