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Marine Turtle Newsletter 68:8-13, © 1995

Marine Turtle Newsletter-Online

Status of Nesting Populations of Sea Turtles in Thailand and Their Conservation

Sam Settle
Marine National Parks Division, Office of Natural Resources and Conservation, Royal Forest Department, 60 Phayolothin Road, Jatujak, Bangkok 10900, Thailand
Present address: Suan Mokkh, Amphur Chaiya, Suratthani 84110 Thailand

In support of informed and wise management of sea turtles inhabiting its national parks, Thailand's Office of Natural Resource Conservation (ONRC) recently undertook an evaluation of the status of the country's sea turtle populations and the various conservation programs. As part of this evaluation, the author participated in a study (July 1993-July 1994) to collect information on nesting beaches in Thailand. Although the scope of the problem of declining populations is broader than the situation as seen from the nesting beaches, limited time and manpower restricted the study to nesting and hatching phases of the life cycle. The study did not address threats at sea. Data were gathered via surveys of park superintendents, conversations with park staff and villagers in and around protected areas, and communication with Fisheries Department personnel, Navy officials, and non-government organizations.

Four species are found in Thailand: Dermochelys coriacea (leatherback), Chelonia mydas (green turtle), Eretmochelys imbricata (hawksbill), and Lepidochelys olivacea (olive ridley). A fifth, Caretta caretta (loggerhead), is believed to be extirpated in Thailand. In general, all populations are seriously reduced from previous levels. By 1989, fewer than about 550 clutches were laid annually along the west coast of Thailand, presumably by fewer than 200 turtles. The majority of eggs laid each year are eaten by people. As a result, only 2,000 to 4,000 hatchlings were produced annually in several years preceding 1988 (Mortimer 1988). This is equivalent to the seasonal reproductive output of fewer than a dozen female turtles. Countless conversations with coastal villagers reveal a rapid and drastic decline in nests in the past two decades. Conservation programs have increased in quantity and visibility, but the annual number of clutches continues to decline in all but one well protected area, Ko Khram.

It is clear that the dominant threat to sea turtle survival is human activity, including egg collection and turtle hunting. Indirect take in fishing gear (e.g., trawlers, drift nets, purse seines) also plays a significant role. In addition to consumption of meat and eggs, shells are fashioned into ornamental objects (e.g., eyeglass frames, earrings). The loss of nesting habitat to beach-front development is another serious threat. Because coastal lands are administered by several different agencies as well as by private individuals, there is no standard approach to sea turtle conservation in Thailand. The Navy, the Fisheries Department, private citizens and the national parks each have control over some of the nesting beaches or administer conservation programs. From one national park to another, approaches to sea turtle management differ. The result is that there are a variety of management practices and beliefs. For example, while some areas release hatchlings immediately, others practice "headstarting". Similarly, some groups stress the importance of community involvement, while others do not involve villagers at all.

The practice of headstarting, or raising hatchlings in captivity for a period of time to (theoretically) enhance their chances of survival at sea, is a popular and deeply established practice in Thailand. The argument is that if the turtles are kept in a safe environment away from predators during their early months, the number that reach sexual maturity is greater than that which occurs when turtles are released immediately after hatching. The primary argument for immediate release (the alternative to headstarting) is that there is no conclusive evidence that head started turtles have a higher survival rate or that they are able to return to their natal beaches at sexual maturity to breed. Other arguments in favor of immediate release include

  1. hatchlings need to imprint on their natal beach and nearshore waters in the early days of their lives,
  2. poor conditions (lack of exercise, improper diet, crowding, water borne infection, injury/biting by other turtles) in headstart tanks interfere with proper development, and
  3. headstarting in no way addresses the root cause(s) of population decline (Pritchard 1980; Hewavisenthi and Kotagama 1990; Frazer 1992).

Nesting areas: During the course of our study, several significant nesting sites were documented. We believe that each of these should be rigorously protected and that management decisions should seek to protect individual breeding stocks, since nesting aggregations of sea turtles are often genetically distinct (e.g., Bowen et al. 1992). Khram Island, in Chonburi Province is the most important site for greens and hawksbills, with an estimated 51 green and 13 hawksbills nesting in 1993. Khram and surrounding islands have been under the administration of the Navy since 1950. A conservation and headstart program was begun there in 1992. Only 27 people live on the islands (all Navy personnel) and nests are therefore virtually free of human molestation. Nearly all nests are moved to hatcheries and nearly all hatchlings are head-started.

The next most important site nationally for hawksbills and possibly greens may be Mu Ko Chang National Park in Trat Province. Unfortunately, no data for the park was available. There are only sporadic reports of recent nesting. To the south of the main island is the Ko Rang Archipelago which is designated a marine conservation area by the park administration. There is a ranger station there, but the extent of conservation efforts and the number of turtles using the area are not known. Anecdotal data indicate that hawksbills nest there.

Similarly, data are lacking for Kra and Losin Islands, both located off the east coast of the Malaysian Peninsula, but the habitat is promising and worth investigating. Kra Island, ca. 50�km east of Nakornsithammarat Province, is abandoned and sporadically checked by the Navy. Only a small southern beach is used for nesting, probably by hawksbills and/or greens. In 1984, it was possible to find ten nests at any one time during the nesting season. Verbal reports indicate that nesting occurred as recently as two years ago. Losin Island, more than 60 km off the coast of Songkla, is another possible nesting site for greens, hawksbills and leatherbacks. Villagers in Ranod District in Songkla reported that turtles still nest there; more specific information was not available. The island's distance from the mainland has perhaps protected nests there from human predation.

Hawksbill turtles are the dominant nesters on the west coast. Mu Ko Surin National Park is the most important site on the west coast for hawksbills, with an estimated six nesting females in the 1993-94 season [N.B. The total number of nests (collected + poached), n=23, was divided by four, the estimated average number of clutches/female.] This group of five islands lies more than 50�km off the coast of Phangnga Province. The two largest islands have a combined area of only 31�km2; the total for the park is 135 km2. The park has numerous short, sandy beaches. Surin Tai Island is home to a small village of sea gypsies who have traditionally eaten turtle eggs (Stuart and Cartin 1994). Mu Ko Similan National Park directly south of Mu Ko Surin is another potentially important nesting ground for hawksbills. The park is a chain of nine small islands covering 128�km2. Unfortunately, the park has many problems with tourism and has allocated few of its scarce resources to conservation. Sea turtle nesting/sighting records are not kept by the park. Based on evidence from other nesting areas along the Andaman Coast, Similan may support seven nesting females per year, at best.

Nesting on the west coast by species other than hawksbills is rare. Green turtle nesting appears to be restricted to Tarutao National Park, a group of mostly unoccupied islands off the coast of Satun Province. In the 1993-94 nesting season, three green turtle nests were recorded at Tarutao. Olive ridleys occur in low numbers along Thailand's Andaman coast. No one area has recorded more than the equivalent of four nesting females for any of the past three seasons. Leatherbacks are limited to the Phuket and Phangnga coastline from Sirinat National Park north through Khao Lumpee-Haad Taimuang, National Park. In the 1992-1993 season, there were at least 28 leatherback nests in this area, which includes two parks separated by a long beach to which villagers have unrestricted access.

In addition to the relatively important sites described above, sea turtles nest in several other areas at very low densities. On the west coast, Laem Son National Park (Ranong Province) recorded one leatherback nest in the 1993-94 season. The beaches of Prathong, Khokhoa, and Ra Islands in Phangnga Province recorded "several" nests last year. Ko Tachai, between Ko Surin and Ko Similan, had at least one nest, as did the north end of Ko Lanta. Finally, reports from the coast of Trang and Mu Ko Petra National Park indicate that olive ridleys are nesting there.

Conservation efforts: strengths and weaknesses: Thailand lacks complete distributional data for sea turtles. A few site managers keep good records, but the vast majority do not. In particular, information from Mu Ko Chang and Mu Ko Similan National Parks is essential to understanding the national situation. A few dedicated persons notwithstanding, many park superintendents and workers lack scientific training and an understanding of basic conservation biology which would enable them to collect data and carry out effective resource management. There are other obstacles impeding conservation. Many parks are popular recreation destinations and park manpower and resources are allocated primarily to visitor services; little energy or money is devoted to natural resource management. Further, headstarting is well established among Thai government agencies. Despite the generally accepted scientific opinion that head-starting is not a valid conservation method (at the very least, its value has yet to be demonstrated), it continues to be popular. Alternatives are rising in prominence, however, and in some places emphasis has been placed on habitat preservation.

It is important to realize that there is no clear link between the high numbers of turtles at Khram Island and the headstart program there, which was established in 1992. The effects, positive or negative, of headstarting will only be seen after two to four decades if and when the raised creatures return to breed and nest. In the interim, Thailand will lose its sea turtles for sure if "conservation" is limited to headstarting. It is essential to the long-term survival of sea turtles in Thailand that resource managers understand what the threats are and how to effectively counter them. Simply raising more turtles and introducing them into habitat ill-suited to support them is a waste. Most areas are heavily populated and conservation initiatives must take this into account. Work done by the coastal villages of Trang (with support from the Raindrop Association) is outstanding in that the villagers are practicing conservation using methods which imitate natural processes. Furthermore, their methods address the root causes of decline, namely, the popular practice of eating turtle eggs and the fishing methods which ensnare turtles.

The importance of continuing conservation: Because Khram Island has been protected by the Navy since 1950, there is likely to have been considerably more recruitment (i.e., young turtles emerging safely from their nests and surviving to sexual maturity) to that population in recent years than to other populations in Thailand that have been heavily exploited. The fact that the nesting beaches have been protected for more than four decades is the logical reason for the relatively high number of nesting females seen there today. By the same token, the results of conservation efforts today will be visible in decades to come. For this reason, it is essential to maximize the number of protected nests everywhere and the hatch rate of each nest. An egg must hatch before the turtle has any chance to mature and reproduce; thus, ending the devastating practice of egg collection is essential. It is important that marine problems also be addressed.

Recommendations: The study (Settle 1994) offers two sets of recommendations: those geared to the national policy level (the ONRC) and those geared to park or local administrative levels. First, to the ONRC:

  1. Recognize the parks which have critically important nesting sites and improve the quality of sea turtle management programs. Specifically,


    1. Mu Ko Surin National Park, with the largest population of hawksbills on the west coast, should be encouraged to continue efforts. Two staff members should be dedicated to the sea turtle conservation project. ONRC staff knowledgeable in sea turtle biology and conservation should visit and maintain contact with staff members working with turtles, particularly just before and during the nesting season to ensure quality record-keeping and field technique. The good relationship recently cultivated with the sea gypsies is vital and should be continued. The park should have funds at the beginning of the season with which to buy eggs; the gypsies should be encouraged to retrieve the nests quickly and with care.
    2. Khao Lumpee-Haad Taimuang and Sirinat National Parks serve as the last refuge for leatherbacks. The ONRC should initiate and maintain contact with the staff at Haad Taimuang responsible for turtle conservation, encouraging them to continue their valuable work. The park should establish a closer relationship with villagers living near the park.
    3. Mu Ko Chang and Mu Ko Similan National Parks may have significant breeding populations of green and hawksbill turtles, respectively. Park superintendents should be contacted and invited to provide information regarding the status of turtles in their areas. They should be encouraged to initiate nightly or morning beach surveys and to collect baseline data. At Similan, in particular, important nesting beaches should be identified and access to these beaches by tourists should be restricted. The waters offshore these beaches should be no-anchorage zones.

In addition,

  1. Develop a national sightings database for sea turtles (nests and at-sea observations), especially for areas under parks jurisdiction. The ONRC should strive to maintain contact with superintendents and staff involved in turtle conservation and emphasize the importance of their efforts.
  2. Discuss headstarting with park superintendents. Ask them to consider the view that headstarting is not a proven conservation method and, as far as possible, discourage them from continuing or starting such projects.
  3. Recruit graduate, third, and fourth year university students into turtle research.

Recommendations to park administrations and local government agencies include:

  1. Increase understanding among park staff, visitors, and villagers of sea turtle biology and conservation.
  2. Strongly encourage participation by local people in conservation activities.
  3. Keep records of sea turtle sightings and tracks, and of all data collected during the course of conservation activities.
  4. Protect the most important nesting beaches. To promote the recovery of depleted stocks, we suggest that at least 70% of nests produce hatchlings and that efforts should aim for a hatch success rate (from individual nests) of at least 80%. This should not be difficult if egg theft can be effectively countered and beaches protected from tourists.
  5. Establish regular and well-managed patrols to document nesting activity. Assign one or two staff people to work specifically with turtles.
  6. If possible, leave the original clutch in situ. If it must be moved, make sure that good technique is used (i.e., eggs must be handled with care, shaded from the sun, not be in transit for more than an hour, and should not be moved if more than 12 hours have passed since deposition).

Bowen, B. W., A. B. Meylan, J. P. Ross, C. J. Limpus, G. H. Balazs and J. C. Avise. 1992. Global population structure and natural history of the green turtle (Chelonia mydas) in terms of matriarchal phylogeny. Evolution 46:865-881.

Frazer, N. B. 1992. Sea turtle conservation and halfway technology. Conservation Biology 6(2):179-184.

Hewavisenthi S. and S. W. Kotagama. 1990. The effect of retaining turtle hatchlings in tanks before their release. Proc. Sri Lanka Assoc. Advance. Science 56(1):92 (abstract).

Mortimer, J. A. 1988. Pilot project to promote sea turtle conservation in south Thailand, with recommendations for a draft marine turtle conservation stratify for Thailand. Report to Wildlife Fund Thailand and World Wildlife Fund USA. 58 pp. Unpubl.

Pritchard, P. C. H. 1980. The conservation of sea turtles: practices and problems. American Zoologist 20(3):609-617.

Settle, S. 1994. The Status of Nesting Populations of Sea Turtles in Thailand and Their Conservation. Marine National Parks Division, Royal Forest Department. Submitted to the Office of Natural Resource Conservation, Bangkok. 26 pp.

Stuart, E. and M. Cartin. 1994. Conservation of sea turtles at two national parks on the Andaman Sea coast of Thailand. Marine Turtle Newsletter 67:6-8.