FIJI MANTA RAY PROJECT

Manta
T R U S T
FIJI MANTA RAY PROJECT
Yasawa Islands | End of Season Report 2014
Conservation through research, raising awareness and
providing education, influence and action.
- The Manta Trust
www.mantatrust.org
PHOTO © Matt Hardy
SEASON OVERVIEW
The 2014 manta-season marks the third year that the Fiji Manta Ray Project has been in operation. A total of 146 days
were spent in the field between June and November 2014, with the project operating from the Barefoot Island resort in
the Yasawa Islands for the majority of this period. In comparison, during the 2013 season 117 days were spent in Fiji
across June to October.
During the 2013 season the island’s mantas were still seen throughout October, and so it was decided that the project
would be extended in 2014. We will now be using this knowledge to plan for the length of the research season in 2015.
End of Season Manta Ray Population Summary:
Table 1: Manta sightings data for Barefoot Channel in 2013 and 2014, over the June to November season.
Year
No. of days
No. of days
mantas
present
No. of
individual
mantas
Average no.
mantas per
trip
Total
sightings of
mantas
Most mantas
seen at once
2013
142
112
41
3
410
13
2014
205
168
55
3
583
14
Total No.
Mantas
Males
Females
Juveniles
Black
Chevron
(white)
Pregnant
Re-sighted
55*
28
22
4
32
23
6
78%
* One of unknown sex
www.mantatrust.org
2
Manta Ray Population
A total of 55 different reef manta rays (Manta alfredi) have been identified within the channel area since September
2012, when the project first started (Table 1). In 2014, 14 new mantas were recorded at the site. It could be that these
mantas previously sought alternative feeding areas or they were coming into this area to breed. Once in the area these
new mantas continued to periodically return to the channel throughout the season. In fact, one of the most regularly
sighted mantas during the 2014 season was one of the new individuals - M68 was first seen on the 29th May 2014,
and was sighted a total of 41 times throughout the remainder of the season. Based on the available data, we speculate
that there is mixed seasonality across this small manta population, with certain individuals returning to the area every
year and staying in the vicinity, whilst others may only come into the area every few years. This opens up the possibility
that the site may have a lot larger reproductive significance than previously thought. There may also be an element of
learned behaviour involved, as mantas that do not know the area learn the location of the best sites off of the frequent
visitors.
Re-sighting levels are high for this site. Mantas are typically seen for a few weeks in a row or on-and-off throughout the
season. There are a number of individuals that are regularly sighted every season, with four mantas being seen over 40
times each in 2014. This accounted for over 45% of sightings this season. A total of 13 mantas were recorded in 2013
but not in 2014 - although the most frequently sighted of these individuals was only seen on six different days in 2013.
Seasonality
The 2014 season started earlier than in previous years. Increased numbers of mantas, and sightings on consecutive
days started at the end of March. This is in contrast to 2013, when regular visitations did not start until late May. The
season in the Yasawas appears to come to a close in mid-October; however a number of unpredictable sightings occur
after these dates. During the off-season mantas can be seen for a few days at a time, but there will typically be a period
of a few weeks or months between sightings. We believe that some of the mantas remain in the area and come to the
channel when the conditions are favourable, whilst the majority move elsewhere.
As this project is still in its infancy many of the current trends that have been observed may gain more or less significance
over time. For example, the large difference between the observed start of the 2013 and 2014 season may be a regular
fluctuation, or an anomaly.
A correlation between the seasonality of the mantas and the water temperature in the area may explain the difference
between 2013 and 2014. The water temperature was 1-2°C lower during 2014 than in 2013 (personal observations/
dive computers). This may have led to the mantas migrating to the site when the water cooled. The cooler water may
have also led to a plankton bloom, a food source that the mantas followed into the area. From satellite photos of the
phytoplankton in the area it appears that there were earlier blooms in 2014 than 2013.
Reproduction
Throughout 2014, manta mating trains were observed within the channel. There was an increase in this behaviour from
2013, although the mating trains generally included fewer individuals. In late August there was a female seen being
followed by two to five males for a number of days. Before this she had not been followed. On one of these days she
came into the channel and was barrel rolling in shallow water with the males following closely. Over the next few hours
her movements became faster and more unpredictable – it appeared as if she was trying to escape from the males.
During this time the males stayed behind her and jostled for position. If one of the males lost the group they then became
extremely agitated until they found them again. The female then left the channel and returned a few days later with a fresh
mating scar on her left pectoral fin. This soon healed. There were also up to 18 remoras now attached to her. This female
had been seen pregnant the previous year, with the birth likely taking place out of season, between October 2013 and
www.mantatrust.org
3
April 2014 (we did not sight her between these
dates). This means there was a maximum of
10 months between giving birth and the next
mating, with it likely to have been a lot less as
she was not heavily pregnant when she was
seen in 2013. In other manta studies it has
been noted that mating does not always lead
straight to pregnancy, therefore mantas are
likely able to store sperm, possibly for a few
years at a time. It will be interesting to see if
M18 is pregnant in the 2015 season. Due to
the lack of knowledge on manta reproduction
any information we gather is hugely beneficial.
Another interesting manta was M53. Over a few
days in July 2013 she was seen being followed
by a large number of males (maximum 6) in
a mating train. This year she was first seen
Picture 1: M12 heavily pregnant and being followed by other mantas
on the 24th August 2014
heavily pregnant in June and was still pregnant
when last sighted in August. During this time
she was still being followed by males but they were not the same individuals. Heavily pregnant mantas are often
followed by groups of males that attempt to mate straight after the birth. It is highly likely that she was lightly pregnant
in August 2013, however no clear pictures are available to confirm this. This would give her at least a 12-13 month
gestation period.
Finally there was a birth during this season. M12 was seen heavily pregnant on the 24th August 2014. The next time she
was re-sighted on the 8th September, she had given birth. As no manta has been seen giving birth within the channel
area we suspect that they go elsewhere. New juvenile mantas have not been recorded since these births, so there
must be alternative sites in the area where the mantas feed. Of the mantas that come to the channel there are a few
juveniles (<2m) who have been sighted for a number of years. Throughout this time they do not appear to have grown
significantly, thus reinforcing the belief in the slow growth rate and time to reach sexual maturity of mantas.
With the increased reproductive activity this year it has been hypothesised that the channel may be a vital mating
area rather than one used solely for feeding. Generally speaking, if a large number of mantas is observed entering the
channel, then it will likely be a mating train made up of a few females and a higher number of males. Throughout the
season the mantas came into the channel when there have been low plankton levels and then inversely have not turned
up when there is a plankton bloom. The mantas were also a lot more unpredictable this season compared to previous
years, and would often come into the channel only to leave 20 minutes later. In comparison, they normally stayed for a
few hours in previous seasons. This may have been because they were not coming into feed, but were seeking potential
mates instead.
Manta reproduction is one aspect of manta biology that the Fiji Manta Ray Project will continue to focus on in the future.
Environmental Factors
As previously mentioned, the mantas first appeared in the channel early in 2014 relative to the 2013 season. This may
have been due to an earlier decrease in water temperature than the previous year. These temperatures may have
caused earlier plankton blooms. Over the next few years we intend to look into how temperature affects the migration of
the mantas at this site and in other sites around Fiji.
www.mantatrust.org
4
The local weather also varied compared to previous years. There were points during the season where the wind direction
came from the West rather than the South East. This did not happen in the whole of the 2013 season, and is normally a
phenomenon that occurs in the Fijian summer months, often leading to storms and changeable weather. This may have
been another factor contributing to the unreliability of the mantas this year. Normally the wind blows from the South East,
which combines with the current at high tide and helps to push the plankton into the channel between the two islands. If
the wind is working against the current then less plankton will be forced into this channel and so the plankton will not be
as concentrated. The unreliability of this food source may have driven the mantas to search elsewhere for food. This is
supported by the number of days at the peak of the season when mantas were not present. Mantas are normally present
on the majority of days, especially in the months of July and August (2013 = at least 112 days out of the 142 day season).
During the Fijian winter months the Yasawas are relatively dry, with rain only falling for a day or two every couple of
weeks. This year there was a 6-9 month drought before and during the manta season. This along with the other differing
environmental factors led us to suspect that there is either an El Nino event currently happening or one beginning.
However it is unlikely that we will be able to confirm that this is happening for another few years, as it is not possible to
ascertain whether an El Nino event is unfolding until a few years have passed. Nonetheless, seeing the potential effect
of the altered climate on the mantas and their behaviour, it raises concerns not only for the mantas, but the environment
and the people that rely upon it.
Tourism
In 2013 a meeting was organised with a number of resorts in the area. This led to the support for guidelines to be put
in place for manta interactions in the channel. A focus of this year has been on reinforcing these guidelines and making
Picture 2: An aerial view of the channel with a manta (centre of picture) and guests. Naviti Island is on the right and
Barefoot resort on the left (top of the photo is East).
PHOTO © Matt Hardy
www.mantatrust.org
5
sure captains and guides are adhering to them. Over the past three years we have made a number of contacts with
other resort captains and guides. This has greatly helped us with implementing the changes in the channel. From this
I have been able to advise on captain and guide behaviour while out in the channel. There is still a large amount of
work to be done to get every resort complying with these rules; however we are progressing along the right lines. In
the future there is a hope that the area can be presented as an excellent example of sustainable tourism within Fiji,
and gain governmental protection. Hopefully this would then lead to worldwide recognition of Fiji as a hotspot for manta
encounters, and draw in more environmentally conscious guests.
A new idea introduced this year has been to conduct compulsory manta briefings two times a day, for guests that wish to
see the mantas. These briefs consist of a 10 minute talk on what to expect in the channel (strong current etc.), what to
do and not to do when mantas are present, and then a small section on manta biology. These were brought in as a way
to give people a greater understanding of the mantas (which they do not get from the other resorts) and to help deliver
a less chaotic experience in the channel. Since we started conducting these briefings, we have received a number of
excellent comments both in person and on Trip Advisor. There is a feeling among guests that Barefoot Island Resort
now offers the best and most professional experience in the area. Through these briefs they see that it is possible for
tourism and the environment to coexist. This educational tool is also spreading the idea of environmental conservation.
Table 2: Tourism data collected from 9th June 2013 –4th Oct 2013/6th June 2014 – 20th Oct 2014 for Barefoot Channel. (The
number of guests is higher than presented here as detailed tourism data only started in June).
Year
Average No, of
Boats per Visit
Average No.
Guests at Site
Average No.
of Guests +
Guides
2013
5
36
43
2014
6
39
45
Year
Total No.
Paying Guests
Total No. of
Boats
Total Money
Raised (≈
FJ$35 charge)
2013
4206
594
2014
4968
744
Highest
Number of
People in One
Visit
Average Time
Spent at Site
(minutes)
Average
Money Raised
per Barefoot
Trip
Total No.
People Visited
Site
130
(115 guests)
45-60
FJ$ 480
4995
119
(95 guests)
60-70
FJ$ 576
5686
Total No. of
Barefoot Trips
Total No.
of Barefoot
Guests
Average No.
of Barefoot
Guests
Total Money
Raised by
Barefoot Trips
FJ$ 147 210
89
1067
12
FJ$ 42 680
FJ$ 173 880
86
1184
14
FJ$ 49 728
The results for this year show an increase in tourist activity both at Barefoot and other resorts. This is positive news for
the local area and shows how vital a set of guidelines for the area is. The total number of tourists and boats will be larger
than shown here as continual monitoring of the channel could not be achieved. Unfortunately due to the nature of the
site, boats will continue to show up throughout the day whether mantas are present or not. This is especially evident with
small yachting tenders, as they do not know the correlation between the mantas’ appearances and high tide. Informing
yachters of the guidelines within the channel is a challenge we will attempt to address in 2015. It is hoped that we can
collaborate with Musket Cove (a site the yachts come into before heading up the Yasawa Islands) to provide guidelines
and information to all individuals that want to see the mantas.
Barefoot totals will also be higher than recorded in Table 2. This is because mantas were present in the channel 55 days
before the Fiji Manta Ray Project began operating in 2014. The increase in revenue taken in 2014 to 2013 is through
both increased guest numbers and the increase in price from $40 - $42. This extra $2 is used to help the conservation
efforts in the area.
www.mantatrust.org
6
100
90
80
70
60
Occupancy (%) 50
40
30
20
10
0
2012
2013
2014
Figure 1: Barefoot Island resort monthly percentage occupancy from 2012 – 2014. Peak occupancy
between May – August each year coincides with manta season.
These results and that of Figure 1 show the huge importance of the mantas within the area and why we strive to
understand and protect them.
Project Examination
Current research being done as part of the Fiji Manta Ray Project:
1. Photo Identification – This comprises the majority of the time and effort invested in the project, and is conducted
daily. With the photos of the unique underside of the mantas we can learn more about many aspects of manta
biology including population numbers and pregnancies. It is also hoped that with collaboration between individuals
across Fiji we can start to understand manta migration patterns within the country. This will help us in working out
where the Yasawan mantas go out of season.
2. DNA Sampling – ran in conjunction with Manta Trust’s genetics project run by Jane Hosegood and Emily Humble.
Nine samples were collected in 2014 from males, females, chevron and black morph mantas. These were collected
to set up a global database that will hopefully be used in efforts to prevent the illegal trade in manta ray products.
Currently they are being stored and analysed at Bangor University, Wales. With more samples it is hoped that we
can gain a better understanding of the Yasawan manta population and its possible links to others around Fiji.
This aspect of the project experienced a few teething problems this year as we got to grips with the equipment
and the techniques used to collect samples. For this reason it was beneficial that Emily Humble came out for a few
weeks this season to help us in the field. The biggest problem was taking samples from the black morph mantas,
as their skin seemed to be tougher than the chevrons. The timing of when we took these samples was also crucial
as we did not want to prioritise this over guest interactions. We therefore mostly went out after the guests from all
resorts had seen the mantas.
3. Environmental Recording – Over the past three seasons environmental records have been made, including data
on the tide, weather conditions, water visibility, plankton levels and current strength. Currently this is done using
personal observations and scales e.g. the Beaufort scale, so that each day can be looked at comparatively.
www.mantatrust.org
7
4. Tourism Estimates – The location of the channel means Barefoot Island Resort is ideally placed to monitor visitor
numbers. Both paying and non-paying guests from each resort, and the number of boats that are seen are recorded.
With this it is then possible to estimate how much money the mantas are generating for the local economy.
5. Photographic Drones – Over a few days this season we managed to acquire the use of a small drone with a Go
Pro action camera attached. This was used to take photos and videos of the channel and the outer reef to the East
of the Yasawas. The outer reef is a possible area that the mantas migrate to at night and out of season.
6. Night Observations – On a few mornings, evenings and nights we either dived or took a boat out into the channel
to look for mantas. Unfortunately we did not see any sign of them, however there was still a large amount of plankton
present. We went out a lot earlier this year than in previous years and so managed to be in the channel at first
light. In the majority of cases if high tide fell within a few hours of sunrise there were mantas in the channel already
feeding. Therefore they would have been in the channel whilst it was dark. One interesting behaviour occurred when
a torch was shone at the mantas in the water, causing them to visibly ‘flinch’ and swim off a small distance. This may
have implications for the future of night feeding based tourism activities.
7. Plankton Sampling – A small amount of sampling was attempted this year. A few plankton tows were performed,
however the amount of boat traffic in the channel made sampling difficult to conduct on a regular basis. For this we
used a simple plankton net made on the island so that we could get a basic idea of plankton levels at different times.
We hope to continue to develop this idea next season.
Picture 3: The channel between Naviti (top of photo) and Barefoot resort (bottom of photo). The darker area is a section
of coral where the mantas feed against the current.
PHOTO © Matt Hardy
www.mantatrust.org
8
8. Acoustic and Satellite Tagging – At the beginning of the season there was a hope we could begin to track
migration patterns. We were approached by a private party who were interested in funding this project. Plans and
quotes were drawn up and they decided that they would be willing to put forward NZ$10,000. This was sufficient to
cover half the planned project, unless things were scaled down.
They asked that we gain further funding from either the resort or another interested party that this would benefit.
Consequently it was decided that we postpone deployment of this project until we can match the funding from other
sources. The delay will ultimately result in a more thorough and insightful study being conducted. We met up with
the private funder during the season and they expressed their desire to continue, as well as stating that they would
consider giving more if satellite tagging were possible.
9. Go Pro Time Lapse Photography – To gain a better understanding of manta movements within the channel we
placed Go Pro’s at certain locations. These cameras were often placed during periods around low tide, as the
mantas are more unpredictable at this time. From these shots we managed to get positive manta identifications that
we would not otherwise have seen. We hope to use this idea in future to improve our coverage of the site.
To enable the advancement of the project we enlisted the help of Beqa Adventure Divers. They allowed Manta Trust and
Barefoot Island Resort to be covered under their local research visa. A Memorandum of Understanding was drawn up
and signed by both parties.
The Future of this Project
After a successful 2014 season we are now looking at ways to continue and expand this project. The continuation of
current research activities, such as identification and DNA sampling is of particular importance. We hope that more
environmental data can be recorded after testing some possible ideas this year. For example, there are potential plans
for temperature loggers to be put in place in the area, as well as more structured plankton sampling. Having briefly
tested a drone this year, there is a hope we can acquire one for 2015. This drone would be used to gain a greater
understanding of visitation patterns to the channel. It would also be used to plot the outer reef and then track shallow
swimming mantas.
www.mantatrust.org
9
Due to visa constraints and the possibility of Fiji wide expansion, it has been suggested that two volunteers are enlisted
for three months each (June – August and September – November), who would take on the same role at Barefoot Island
Resort as the Project Leader, Stephen Pollett. This would involve taking guests out to see the mantas, taking ID photos,
recording environmental / tourist data, conducting Manta Briefs, helping the dive shop with day-to-day logistics and any
other required research. To determined suitable candidates, interviews would be held with Barefoot Island Resort, the
Manta Trust and the Project Leader.
With increased mobility we would be able to focus on finding alternative manta sites around the Yasawas using tags
and/or drones. With volunteers continuing operations at Barefoot, there is also an opportunity for the Project Leader to
visit other places and groups around Fiji who have expressed an interest in working with the Fiji Manta Ray Project. As
we have recently received photos that may show a Yasawan manta elsewhere in Fiji, being able to move around the
country will enable us to develop a country-wide understanding of the manta populations in Fiji. In turn, this will help to
coordinate plans for governmental protection, as well as facilitate other collaborations.
In terms of social media, it is suggested that the project should have more of a presence on the Barefoot Facebook
page to promote both the Manta Trust and the resort. Next year we intend to have more photos and blogs that link to the
research being done at the Yasawas and in Fiji as a whole.
Acknowledgements
We would like to thank Barefoot Island Resort and Reef Safari Fiji for helping to make 2014 another successful manta
season and we hope this can continue for many years to come! The research conducted this year contributed to the
scientific knowledge that enabled the successful listing of reef manta rays, under the Convention for the Conservation of
Migratory Species of Wild Animals. With the help of Barefoot Island Resort, we hope that we can continue to contribute
to conservation successes for manta rays, both in Fiji and around the world.
Manta
T R U S T
For more information, please contact
STEPHEN POLLETT | FIJI PROJECT LEADER
steve@mantatrust.org
Content written by: Stephen Pollett | Report created by: Danny Copeland
The information and ideas within this report are the intellectual property of The Manta Trust. Any scientific data distributed to our collaborators and
partners belongs to The Manta Trust and are not to be shared with a third party without prior permission from The Manta Trust.
www.mantatrust.org
10