Sea turtle populations and habitats in the Chagos Archipelago

During a six-week period in February/March 1996, a survey of 49 islands and 110 of the 226 km of the total coastline of the Chagos Archipelago indicated significant levels of nesting by both green turtles (Chelonia mydas) and hawksbills (Eretmochelys imbricata) on the 59-70% of the coastline that provide suitable nesting habitat. Hawksbill nesting was most concentrated on Peros Banhos and Diego Garcia atolls, while green turtles nested most abundantly on the islands of Egmont atoll, followed by Diego Garcia, Chagos Bank (especially Danger Island) and Peros Banhos. Populations of immature hawksbills forage on the extensive coral reef systems in the lagoons and seaward slopes of the Chagos atolls, and also occupy the _barachois? habitat of Diego Garcia (narrow extensions of the inner lagoon comprising areas of intertidal sands and gravel). Sea grass occurs sparsely in Chagos, but immature green turtles inhabit the lagoon at Diego Garcia. The populations of both species in Chagos are of global significance given the _Critically Endangered? status of hawksbills and the _Endangered? status of green turtles on the IUCN Red List. Chagos turtles were exploited during the previous two centuries, but they and their habitats are now well protected by the administration of the British Indian Ocean Territory. The long-term survival and continued recovery of the turtle populations would be enhanced by programmes to: i) conduct long-term monitoring of nesting and foraging populations in order to identify critical habitat, define the nesting seasons, and evaluate long term population trends; ii) conduct a public awareness campaign to sensitize base personnel; iii) improve surveillance of fishing vessels to discourage turtle poaching in the outer islands; and iv) eradicate rats and feral cats to minimize predation on turtle eggs and hatchlings.
Mortimer Jeanne , Day M .
turtles, Green turtles, Chelonia mydas, Hawksbill turtles, Eretmochelys imbricata, Nesting habitat, Foraging habitat, Population surveys, Chagos Archipelago, Exploitation,Conservation