GEIS, A.A.*; WIBBELS, T.; VEGA, L.; LIRA, D.; ACOSTA, R.; PENA-V, J.; BURCHFIELD, P.; SCHROEDER, B.; Univ. of Alabama at Birmingham; Univ. of Alabama at Birmingham; Instituto Nacional de la Pesca, Mexico; Instituto Nacional de la Pesca, Mexico; Instituto Nacional de la Pesca, Mexico; Gladys Porter Zoo, Texas; Gladys Porter Zoo, Texas; National Marine Fisheries Service, Maryland: Six-year Evaluation of Hatchling Kemp’s Ridley Sex Ratios Produced in the Conservation Program at Rancho Nuevo, Mexico

The Kemp’s ridley (Lepidochelys kempii) is one of the most endangered sea turtles in the world. Like all species of sea turtle, the Kemp’s ridley possesses temperature-dependent sex determination (TSD) which has the potential of producing biased sex ratios. In some cases, strongly biased sex ratios may not be advantageous to the recovery of an endangered population. An international conservation program at the primary Kemp’s ridley nesting beach near Rancho Nuevo, Mexico, has been relocating almost every nest to protected egg corrals for over 25 years. The sex ratios produced as a result of this conservation effort are a fundamental component to the survival of this species. Previous studies in turtles with TSD have shown nest incubation temperatures to be an accurate predictor of overall clutch sex. In this study, incubation temperatures were monitored within Kemp’s ridley nests at Rancho Nuevo over a 6-year period (1998-2003). In general, results from each nesting season indicate the production of mostly or all female hatchlings in a majority of monitored nests. No nests were predicted to produce all males. It is plausible that this female bias may enhance the recovery of this severely endangered species.