Grant: 05-019R
Project Title: Simultaneous Evaluation of Loggerhead Nesting Beach Temperatures Throughout Florida: Implications for Population Sex Ratio
Project Manager: Dr. Thane Wibbels
Organization: University of Alabama at Birmingham (Research and Educational Institute)
Grant Amount: $5,428.00
Completion Date: 2007-03-22

Summary: Sea turtles possess temperature-dependent sex determination which has significant implications for their ecology and conservation. In the current study, we propose to use a standardized methodology to simultaneously evaluate nesting beach temperatures on ten major nesting beaches for the loggerhead turtle throughout Florida during the 2005 nesting season. Temperature data loggers will be buried at nest depth in areas where the majority of nesting occurs on each beach. Nesting beach temperatures will be analyzed throughout the nesting season relative to the timing and frequency of nesting loggerhead turtles on each beach in order to predict sex ratios. The results will facilitate the direct comparison of the various nesting beaches and will provide a better understanding of how sex ratios from specific beaches contribute to the overall sex ratio produced from Florida nesting beaches. Finally, the results will enhance our basic understanding of the reproductive ecology of the loggerhead population in the southeastern U.S.

Results: A total of 86 data loggers were deployed for this study in 2005 and 58 were recovered. Although data loggers were lost on several of the nesting beaches due to the abundance of hurricanes, data was obtained from many of the beaches. In general, beach temperatures during the nesting seasons varied relative to weather and, in particular, to precipitation. In general, the temperature variation within a beach was less than the temperature variation among beaches. The results also indicate that some beaches may be consistently warmer or cooler than others. These results indicate that certain beaches my be important for the production of females and certain beaches may be important for the production of males. The findings of this study facilitate the identification of nesting beaches which may be of conservation and management interest due to their thermal characteristics. (Author: Dr. Thane Wibbels)

Full Final Report
Integrative Comparative Biology, Estes & Wibbels Abstract
2006 International Sea Turtle Symposium, Estes & Wibbels Abstract