Worldwide, the outlook for the leatherback turtle appears bleak. They are considered to be “critically endangered,” meaning that they are perilously close to slipping toward extinction. The once large nesting populations on the Pacific coasts of Mexico and Costa Rica have decreased by over 90% in the last two decades! Egg poaching and incidental capture by commercial fisheries are the major reasons for the dramatic decline. Conservationists all over the world are scrambling to reverse the negative nesting trend.
The decline in global nest numbers means that the leatherback research and conservation efforts on the Caribbean beaches of Central America are becoming increasingly important. Tagging and monitoring studies by CCC and others have shown that leatherback turtles nesting on the Caribbean coast of Central America show less site fidelity than do their Pacific cousins. Leatherback turtles that come to lay their eggs at Tortuguero may later emerge to nest in the Pacuare Nature Reserve, the Gandoca-Manzanillo Wildlife Refuge in Costa Rica or even as far away as Bocas del Toro, Panamá. Sometimes they will nest in protected areas and other times on beaches where there are no nest protection or monitoring programs. The lack of strict beach fidelity complicates monitoring and conservation efforts and requires extensive cooperation between organizations and institutions active along the coast. To determine the current trend in nesting, CCC, Asociación ANAI and the Endangered Wildlife Trust have carried out a joint analysis of our collective monitoring data. The results indicate that nest numbers at Tortuguero have remained fairly constant over the past eight years. Apparently, the Caribbean leatherback population is so far avoiding the same fate as the Pacific population.
To get a better idea of the spatial distribution of leatherback nesting along the Caribbean coast, CCC has partnered with Lighthawk, an organization providing overflights for conservation purposes. At least twice per year since 2001, Lighthawk pilot David Smith has flown CCC researchers and colleagues along the entire Caribbean coast of Costa Rica and parts of Panamá to count nests from the air. Based on the aerial surveys’ results, CCC now believes that the nesting aggregation of leatherback turtles coming ashore between the Nicaragua/Costa Rica border to central Panamá represents the third or fourth largest nesting population worldwide (exceeded only by the Guayana, Gabon and possibly Trinidad populations).
The aerial surveys have also confirmed that the highest leatherback nesting occurs along a remote beach in Panamá called Playa Chiriquí. CCC is currently working with local communities, researchers, and funding institutions to initiate a conservation and nest monitoring program for nesting hawksbill (Eretmochelys imbricata) and leatherback turtles at Playa Chiriquí (see the next issue of the Velador for a full story about this exciting new program). CCC is also working with other organizations to establish a joint tagging database for all the leatherback tagging projects along the coast so that information can be shared between conservation projects.
To control poaching, CCC has partnered with several funding agencies to provide extra personnel and equipment to Tortuguero National Park during the leatherback nesting season. The Costa Rica-USA Foundation (CR-USA), International Fund for Animal Welfare (IFAW), the Lemmon Foundation and Care for the Wild International have provided generous support to achieve additional protection for nesting females and their nests during the 2001 and 2002 Leatherback Programs.
Leatherback Program Update
In 2002, more leatherback turtles were tagged at Tortuguero than during any previous nesting season (a total of 172 leatherback encounters were logged). This was not due to more females coming ashore to nest but to the dedicated efforts of CCC Field Coordinator Dr. Emma Harrison and CCC’s team of volunteer Research Assistants. Together, they increased the number of night patrols along the southern section of Tortuguero beach and spent several days based together with park rangers at the Jalova ranger station, located at the southern border of Tortuguero National Park. Many of the leatherback encounters were recorded during the 8 PM-3 AM beach patrols in this part of the National Park.
The first leatherback nests of 2003 have already been laid at Tortuguero. Track surveyor Enrique Vargas registered the first nest on the morning of February 13. Only one nest was laid that night. Enrique also recorded fresh paw prints from jaguars that had walked the beach the same night, probably in the hope of catching an early arriving green turtle.
The 2003 Leatherback Program will be the ninth consecutive year of leatherback monitoring and conservation in Tortuguero. The program has now been consolidated as an integral part of CCC’s conservation efforts in Tortuguero and the region. Hopefully, the leatherback program will eventually become an equally successful and long-term endeavor as our Green Turtle Program, now entering its 49th consecutive year!
If you want to find out more about the results of the 2000, 2001 and 2002 Leatherback Programs, you can download the season reports. If you want to take part in night patrols and track surveys join in the 2003 Leatherback Program.
|Support for the 2003 Leatherback Sea Turtle Research Program was provided through a grant from World Wildlife Fund – Sweden