Nesting success of hawksbill turtles (Eretmochelys imbricata) on Cousine Island, Seychelles
Nesting hawksbill turtles Eretmochelys imbricata were studied on Cousine Island, Seychelles from 1995 to 1999. Mean overall incubation time averaged 58.1 days. Clutch size did not influence incubation periods. Following hatching, hatchlings took an average of 3.8 days to leave the nest. Mean hatchling emergence time was 60.4 days. Hatching success averaged 64.3% for the four seasons. During 1996–97 there were heavy, unexplained egg losses due to crab predation. Excluding that season, average hatching success was 70.9%. Overall hatchling success was 61.1%, translocated nests having a better success (69.3%) than natural nests (57.7%). Overall egg and hatchling losses were 35.8% and 3.1%, respectively, most egg losses being attributed to ghost crabs Ocypode cordimana (16.3% overall) and unknown causes (17.0% overall), which were mainly non-viable eggs. The high level of nest manipulation was believed to be justified by increasing the number of hatchlings entering the sea.(Accepted April 27 2004)
Key Words: Reptilia; marine turtles; Eretmochelys imbricata; breeding; eggs; hatchlings; nest translocations; Cousine Island; Seychelles.
c1 All correspondence to: P. M. Hitchins, P.O. Box 52629, Dorandia 0182, South Africa. E-mail: [email protected]