ZELICKSON, M.; WIBBELS, T.*; VEGA, L.; LIRA, D.; ACOSTA, R.; PENA, J.; BURCHFIELD, P.; SCHROEDER, B.; Univ. of Alabama at Birmingham,; Univ. of Alabama at Birmingham; Gladys Porter Zoo, Brownsville, TX; Gladys Porter Zoo, Brownsville, TX; Gladys Porter Zoo, Brownsville, TX; Gladys Porter Zoo, Brownsville, TX; Gladys Porter Zoo, Brownsville, TX; National Marine Fisheries Service, Washington, D.C.: Histological evaluation of hatchling sex ratios of Kemp’s ridley sea turtles during the 2002 nesting season.

The Kemp’s ridley sea turtle inhabits the Gulf of Mexico and Atlantic coastal waters of the U.S. Due to its endangered status, this species has been the subject of intense conservation efforts over the past three decades. These efforts include the moving of nests to protected egg corrals at the main nesting beach near Rancho Nuevo, Mexico. Since this species has temperature-dependent sex determination, it is advantageous to monitor the incubation temperatures and resulting sex ratios produced in the egg corrals. In the current study, histological analysis was used to sex hatchlings which were found dead in nests after all of the live hatchlings emerged. One to five hatchlings per nest were collected from a total of 50. Kidney/gonad tissue was preserved from each hatchling, and was then histologically processed. Each gonad was examined microscopically to determine if it was an ovary or a testis. The results indicate an overall female bias in the hatchlings examined. These results are consistent with a previous female-biased sex ratio prediction for the 2002 nesting season, based on incubation temperatures. The results also provide insight on the transitional range of temperatures during sex determination in the Kemp’s ridley sea turtle. The result will be beneficial to the development of effective management strategy for the recovery of the Kemp’s ridley sea turtle.