PARK, A.P.*; WIBBELS, T.; LIRA-R., D.; CASTRO-MARTINEZ, M.; VEGA-M., L.; BURCHFIELD, P.; PENA-V., J.; SHROEDER, B.; Univ. of Alabama at Birmingham; Univ. of Alabama at Birmingham; Gladys Porter Zoo; Gladys Porter Zoo; Gladys Porter Zoo; Gladys Porter Zoo; Gladys Porter Zoo; NOAA Fisheries: Episodic Production of Male-Biased Hatchling Sex Ratios in the Kemp’s Ridley Sea Turtle

The Kemp’s ridley sea turtle possesses temperature dependent sex determination (TSD) which can produce a wide range of sex ratios. Therefore, sex ratios produced in nesting beach conservation programs are of ecological interest and conservational importance. Further, the sex ratios produced from natural nesting beaches can be of evolutionary interest. The Kemp’s Ridley Conservation program has historically transferred the majority of nests into protected “egg corrals” at the main nesting beach of the Kemp’s ridley near Rancho Nuevo, Mexico. In recent years, this program has also examined the effect of leaving a portion of nests in situ on the natural nesting beach. In the current study incubation temperatures were monitored within egg corral nests and also within in situ nests in order to estimate sex ratios. Previous studies have suggested that female-biased sex ratios are the norm at Rancho Nuevo. However, the 2004 nesting season was relatively cool, and the results indicate a significant male bias was produced during 2004 in comparison to the previous six nesting seasons (1998-2003). This was the case for both the corral nests as well as in situ nests. These findings illustrate the importance of long-term studies when evaluating sex ratios in sea turtle populations. Moreover, these findings have significant implications for the ecology and conservation of the Kemp’s ridley. It is plausible that a periodic pulse of males may be important to the long-term reproductive ecology of long-lived species with TSD.