PARK, A.*; MORTIMER, J.A.; WIBBELS, T.; Univ. of Alabama at Birmingham; Ministry of the Environment, Republic of the Seychelles; Univ, of Alabama at Birmingham: Evaluation of incubation temperatures in hawksbill sea turtle nests on islands in the Republic of the Seychelles.

Sea turtles, like many reptiles, possess temperature-dependent sex determination (TSD). Hatchling sex ratios resulting from TSD are of interest because they affect the reproductive ecology of a species. Further, sex ratios are of interest to conservationists, because they affect the recovery of endangered species. The hawksbill is a critically endangered sea turtle that is well known for inhabiting coral reef environments. A major population of hawksbills occurs in the waters of the Seychelles in the Indian Ocean. In the current study, nesting beach temperatures and nest incubation temperatures were monitored on several nesting beaches for the hawksbill in the Seychelles from 1999-2003. Data loggers were inserted into nests or buried at mid-nest depth on nesting beaches to monitor temperatures. Each year, 5 to 19 nests were monitored. Nest incubation temperature during the middle third of incubation was used to predict hatching sex ratios. The average incubation temperature varied significantly between nests. The results suggest that a variety of hatchling sex ratios can be produced by these hawkbills depending on the location and timing of nesting.