V. Contacts and collaboration
5.1. Sompotch Nimsanticharenkul
Mr. Sompotch provided a lot of support for the Sea Turtle project this season. He has excellent knowledge of the feeding grounds and the research area. Next year he hopes to become more involved in the Sea Turtle project and we are sure he will be an asset to the project.
5.2. R.C.R.R.S.
Unfortunately Sompotch resigned from his position at the RCRRS early in the season; however we still have contact with the RCRRS through some less well known staff members. The centre was visited on a number of occasions. One female Green turtle was seen appearing healthy, it was reported that she was brought in by a local fisherman and would be released after a brief period of monitoring. Unfortunately we were not witness to her release.
5.3. Phuket Marine Biology Centre
Discussions with Sontaya from the Phuket Marine Biology Centre took place, which proved helpful in keeping up with details about Sea Turtle nesting along the Andaman coast (past and the present). The centre continues to do a lot of research on the Sea Turtle Population of Thailand and is an important resource of information.
5.4. Bundit Chokesanguan
Mr Bundit Chokesanguan is at the forefront of Fishing and Shrimp Trawling regulatory measures for Thailand and South East Asia . Mr Chokesanguan from the SEAFDEC Training Department was consulted on a number of occasions regarding the incidental capture of Sea Turtles in Thai waters and current use and promotion of TED's in Thailand . He gave an overview of what was being done or had been done in Thailand regarding incidental capture and on how successful mitigation measures had been and the plan for the future.
5.5. Naucrates
Naucrates Sea Turtle project is run on Phra Thong Island , south of the research area, it was hoped to organize a visit to this project but unfortunately time ran out. The project has been running for over 8 years and is a useful comparison. Dr Aureggi is keen to keep contact with our project and already proved a valuable contact, for information and swapping ideas about sea turtle nesting/conservation and research within our areas.
5.6. Aleenta Spa Resort and the Haad-Thaymuang centre
We arranged a visit to the Haad - Thaymuang centre (north of Phuket) which is sponsored by Aleenta Spa resort. The centre receives Sea Turtles caught in incidental capture by fishermen, releasing them once they are healthy again. They also run a breeding program and a head start program for Green turtles. Tourists are regularly taken down to the project and shown Sea turtles being released.
Although some things were concerning regarding the centre, Katie McGaulen in charge of the Aleenta Spa Resort Sea Turtle activities was very keen to work with our project. I gave her some feedback regarding the Centre and we have made plans to train their Sea Turtle patrollers in Sea Turtle beach patrols methodology. Also for next season there may be further chance for integration of our projects.
5.7. National Park Staff
Many meetings took place with the staff of Leam Son National park in December. They expressed a keen interest to help us and we arranged for staff to accompany the night patrols down onto the beach. However this fell through at the last moment and no staff was ever provided. No clear explanation was given as to why.
VI. Grants and funding
We applied for two grants to help fund the project in the following seasons; the British Chelonia Group fund and the Mia J. Tegner Memorial Research Grant.
A proposal was also made to the following airlines; Thai Airways, British Airways, Emirates, Air Asia, Qantas, Virgin, Royal Jordanian, Egypt airways, to offer concession or free flights to groups which could then be incorporated into the cost of volunteering and reallocated as a source of funding for the project.
At the time of writing the British Chelonia group application is still being considered. All other applications and proposals were unsuccessful.
VII. Discussion
Last years recorded nesting showed that there were at least two, and probably more, nesting Leatherback females (from looking at the time between nests and comparing to the known inter-nesting period for Leatherbacks, which is 10 days on average (Spotila 2004)).
If the figures, Bung Deed provided us with, are correct.; then for at least the past 4 seasons as few as two or three nesting females may have been laying in this area. And we can assume that the number of nesting females has been decreasing over the last decades to this critically low number.
This year a lot of jellyfish washed up in the area which should have proven favourable as Leatherbacks are known to feed upon them. We hoped that at least some nesting would occur this season and that we could ensure the safety of the nests, but sadly and worryingly, there were no nests at all this season!
To justify the possible cause(s) of these results we first need to look at why the Sea Turtle population in the area got to such low numbers in the recent seasons.
7.1.Discussion A
"How did numbers get so low in the research area and along the Andaman coast?"
A 90% decrease was seen in nesting along the Andaman coast from 1985-1995 (Chantrapornsyl 1997). Two factors are mainly responsible for this decrease .
7.1.1. Shrimp trawling
Mancini & Mairesse (2004) attributed shrimp trawling in off shore waters as a main reason for the decline in Sea Turtles along the Andaman coast. It is largely accepted that worldwide incidental capture in shrimp trawls has had a great impact on Sea Turtle numbers. While other countries have been quick to insist the use of TEDs and regulatory measures Thailand has lagged behind.
From the WWF Amicus brief to the WTO on the shrimp-turtle dispute, it was determined that where gravid females attempting to lay eggs coincided with periods of intense unmodified trawling activity. The result is high mortality! This is the case in Thailand with the intense fishing season that takes place out of the monsoon season completely overlapping with the Sea Turtle nesting seasons, as outlined in Garret and Munchow (2004).
Stage-based population models identified that even if the hatch rate was put at 100% it cannot prevent extinction if the mortality rate of mature adults is high.
During the early 80's commercial shrimp farming had begun and was increasing fast. By the mid 90's Thailand became the worlds leading exporter of farmed shrimp. During this stage the wild gathering of shrimp was accounting for the majority of the export.
A lot of shrimp trawling during these years lead to high mortality of Sea Turtles within this period 1985-1995 from incidental capture.
Each season the breeding population would be reduced significantly due to this mortality and this could have lead to extinction of the population over a period if this pressure continued for a sufficient time; however this factor has not been working alone.
7.1.1.1. Reductions seen to Shrimp trawling pressure
In more recent times the incidental capture of Sea Turtles through shrimp trawling has had some regulation, e.g. a 1992 International Sea Turtle Restoration Project implemented legal strategy and an eventual introduction and promotion of TED's from the SEAFDEC / Training Department to Thailand fishers. Although the success of this action has been criticised stating that only a low number of fishermen use the TED's.
7.1.2. Legal Harvest
Legal annual harvest of sea turtle eggs took place provided by a concession system and supervised by the Department of fisheries in Thailand in past years. This saw an annual harvest of up to 400,000 eggs being taken per year (Polunin 1975). From Phang Nga province alone 60,000 eggs per season were estimated to be taken per year.
Thailand 's fisheries act was implemented in 1975 to protect nesting Sea Turtles however the commercial harvest would have been enough to continue significant reductions in Sea Turtle populations for seasons to come.
The reduction to population caused through egg harvest would not be seen immediately from the first season of egg harvest but would come a decade or more later, depending upon the species as the time it takes to mature varies from species to species. We call this lagged reduction.
If 60,000 eggs were taken from an area each season, around 60 less adults would be expected each consecutive seasons in that area after the original lag (or lags if dealing with different species which mature at different rates).
The government stopped the Legal harvests in most places following 1975; however as the reduction to the Sea Turtle population caused by this harvest would lag over many decades following, this would therefore be a factor in the 90% decrease from 1985 till 1995.
The decrease in the population has continued following 1995, and although the rate of decrease has fallen from 90% it has been enough to continue the extinction of many populations along the Andaman coast.
7.1.3. Poaching
7.1.3.1 Thailand
Even after egg harvest was made illegal Poaching remained at large in the area and also over a lot of turtle nesting beaches in Thailand due to poor enforcement of the law. All though there are some exceptions e.g. Kram Island which has been protected by the Navy from poaching since 1950 and comparatively had a larger population of Green turtles for that reason (Settle, 1995).
7.1.3.2.Research Area
Bung Deed and other people from Baan Talae Nork are known to have been poaching all the nests they found in the research area over the last decade and probably since legal harvest was stopped. Findings from other villages close to the research area show that most of these communities have also been consuming turtle eggs, as recently as last season! This proves other poachers from other villages also work in the research area. Even those beaches out of easy access from local villages are still easily accessible for fishermen. They can distinguish the tracks and nests from their boats which makes the chance that some nests have gone unnoticed extremely slim.
As the number of nests decreased in Thailand and harvest was made illegal the value of the eggs would have increased (at current up to 60baht per egg), making it more profitable and ensuring there were an adequate number of poachers (a surplus in fact) to take all the eggs/nests laid.
7.1.3.3. How many nests have been poached and for how long?
Due to the low number of nests and taking into consideration all the factors mentioned before it is probable that 100% of the nests laid in the research area have been poached for well over a decade! And extending back with a similar high percentage to the time when legal harvest was allowed. This illegal harvest would have understandably been responsible for the continuing drastic decrease in the nesting population number following 1995.
7.1.4. Conclusion
The high mortality of the Sea Turtles especially during the period of increasing export of Thailand shrimp (with high wild shrimp harvests) combined with the lagged reductions due to the legal egg harvests commissioned by the Government, reduced the Sea Turtle population of the Andaman coast and would be the major reasons for the 90% decrease noted by Chantrapornsyl (1997) from 1985-1995.
The efforts of a number of highly influential parties (e.g. WWF, the International Sea Turtle Restoration Project) have been successful in reducing the pressures of shrimp farming since 1996 on the Sea Turtle Population and continue to reduce this pressure.
At present Mr. Bundit Chokesanguan from the SEAFDEC training department has outlined that devices to reduce Sea Turtle capture in shrimp nets, such as TED's are being used and further promotion is taking place (per com)
Poor law enforcement has meant that the pressure on the Sea Turtle population in the area caused by egg harvest has remained, through illegal poaching .
With the low numbers seen nesting and the fact that the nests were unprotected when they were being poached, the supply of future adults has been cut off for a significant time.
Little or even no hatchlings would have entered the ocean with the 1 in 1000 chance of becoming a breeding adult. Therefore at present there are likely no (or too few) up and coming Sea turtles to become future generations of breeding adults in this area.
I want to underline that the findings from this area suggest that the impact of poaching has been overlooked and drastically underrated. The result is that population extinction has or will likely occur considerably sooner than anticipated . Conservation efforts (particularly those aimed at the Thailand government) have been limited in the past failing to account for the high percentage of poaching which was actually taking place!
These findings call for a drastic effort to ensure the survival of any future nests in the area to ensure the chance of a future population, although evidently it may be too late for most or even all of the Sea Turtle species which were known to nest in this area.
One in one thousand hatchlings survive to become an adult!
7.2. Discussion B
"What happened to the remaining adult Sea Turtles this season?"
This season we are quite likely witnessing the beginning of the extinction of the local population. We say 'the beginning' because next season different individuals would be returning to breed. The numbers of nesting females over recent seasons represent the remaining population or generation and confirm we have come to a critical low number of surviving adults.
With the remaining population so low, the cause of death (or resultant behaviour change) to even one individual would contribute very significantly to the results of having no nests, therefore the number of possible contributors is extremely numerous. For this reason we only discuss the more likely causes here.
7.2.1. Human caused mortality
Human caused death in part or whole of this extremely low adult population is possible. They could have been killed anywhere upon their long migration route between nesting seasons
7.2.1.1. Incidental capture
WWF reported that some 50000 Leatherback Turtles are caught globally each year just by incidental capture. As outlined earlier intensive fishing practices in Thailand overlaps with the nesting season and there is a lack of enforcement of TEDs by the government, which further increases the chance of incidental mortality for this population as they return to Thai waters.
7.2.1.2.Increased pressure caused by the Tsunami aid
Adding to this again the recent Tsunami aid has brought with it false claims which means that fishing boats and equipment have actually increased in number in many areas to what they were prior to the Tsunami (Aureggi M. (2006)). From the beaches patrolled in the area a line of tightly dotted lights on the horizon surrounded the area most nights. WARThai staff confirmed that these lights have grown in number dramatically since last season. The increased lights of the fleet alone could have been enough to deter any remaining nesting females getting to the beaches.
The increase in fishing boats and equipment in the area would have caused a greater physical barrier and increased the chance of mortality as outlined in Kartik. S et al (In Press). No Sea Turtles were reported caught by these fishermen (or seen) in this area this season and no dead or injured sea turtles were found washed up.
However Aureggi M (2006 per com) has found sea turtles dead and with serious injuries washed up in the period since the Tsunami in the area of the Naucrates project based on Phra Thong island, suggesting that this increase in fishing boats and equipment described has increased mortality to the critically low Sea Turtle population along the Andaman Coast .
7.2.1.3. Hunting and pollution
Other possible human caused mortalities contributing to the loss of these few remaining Sea Turtles are hunting and pollution. The ingestion of rubbish is commonly seen in feeding Leatherback turtles who mistake plastic bags for prey.
7.2.2. Natural causes
This season's low breeding population quite feasibly could have stopped breeding due to natural causes. They could have died off from predators or disease. Similarly the remaining few could simply have finished their breeding stage of their life (this commonly lasts for less than 20 years). Looking at population models natural fluctuations in number are common within all species, it is possible that one such fluctuation occurred which would have been harmless to a healthy population but killed off the remaining individuals of a critically low population.
7.2.3. Leatherback's changing nesting location
We know four Leatherback turtle nests were observed last season. But at present due, to a lack of data for all of the nests in past seasons we do not know which other species have nested in recent seasons or if other species would indeed have nested in recent seasons in the research area.
Addressing Leatherback nesting separately we must consider the case that Leatherbacks are known to frequently change beaches for nesting, sometimes moving more than 300km between nesting sites within the same season (chan et al 1991). Generally mating also takes place on the migration route to the breeding grounds and subsequent mating would likely take place a significant distance offshore as inter-nesting females seem to return 60km offshore and also sometimes perform extended movements during this time (Georges J-Y (2006)).
The Individual Leatherbacks which have been seen to nest in the area in the past therefore cannot be expected to return faithfully to the same beaches.
This season's nesting individuals likely nested within a different area. If we look at known Leatherback nesting at the time of writing, we see a few Leatherbacks nested on the Andaman coast of Thailand this season: Ko Ra Island had one nest and unexpectedly in Phuket they had 3 nests, at Tai-Muang beach in Phang-nga province they had 8 Leatherback nests.
The individuals who laid these nests could have nested in the research area in past seasons.
7.2.3.1. Reason for changing nesting beach
Currently the precise reasons for a change in nesting beach are undecided.
Natural and unnatural factors have been suggested.
The increased fishing boats with the increased number of lights dotted out in the ocean surrounding the area would be a likely deterrent from the research area.
To compare our area to Thai-Muang which has seen an increase in nesting Leatherbacks, we see that the fishing boats in that area are considerably less and less intrusive.
Approximately 11 boats from these communities fish in waters off the beach in front of the park; however they are very target-specific and fish only for a small species of shrimp (Koong Koey) and use only hand-lines.
7.2.3.2. Assessment of the Leatherback population
To assess this Leatherback population more fully collaboration between projects monitoring nesting beaches along the Andaman coast as a whole is crucial!
More specifically identification of individuals nesting is paramount to further understanding.
Current estimates by the Marine and Coastal Unit suggest this population is hovering on the brink of extinction with less than 5 remaining over an area that once teamed with them. If this Andaman coast population survives then Leatherbacks could be seen nesting in the research area again in the future, despite the lack of nesting at present.
A similar situation could also be seen in other species of Sea Turtle but it would not be as pronounced as it is in the leatherback species.
7. 2.4. Conclusion
The cause of the final loss of the few remaining nesting females this season from the nesting area is probably due either to one of the factors discussed or a combination of them. It cannot be more accurately determined without further in-depth investigation into the factors and more accurate knowledge of all species nesting in recent season. However the increased fishing activity in the area this season is likely to have been significant in the results observed. Further investigation is recommended into this.
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