Pivotal temperature and predicted sex ratios for hatchling hawksbill turtles from Brazil

Like all other species of sea turtle, the hawksbill turtle (Eretmochelys im bricata) exhibits temperature-dependent sexual differentiation, with high i ncubation temperatures producing females and low temperatures producing mal es. Relatively little is known about the sex ratios of hatchlings produced by nesting populations of hawksbill turtles. Here we estimate the overall s easonal sex ratios of hatchling hawksbill turtles produced in Bahia, Brazil , during 6 nesting seasons, based on incubation durations, pivotal temperat ure, and pivotal incubation duration. The overall sex ratio of hatchlings p roduced in Bahia from 1991-1992 through 1996-1997 was estimated to be > 90% female, which is more female-biased than estimated sex ratios of hatchling loggerhead turtles from Bahia and Florida, U.S.A. The biological and conse rvation implications of skewed sex ratios are discussed.