Evaluation of in situ incubation temperatures within Kemp's ridley nests at the primary nesting beach.
Like all species of sea turtle, the Kemp's ridley,
Lepidochelys kempi, possesses temperature-dependent sex determination (TSD). Under TSD, the incubation temperature of the egg during the
approximate middle third of incubation determines the sex of the
developing hatchling. As suggested in previous studies, TSD can
potentially result in the production of highly biased sex ratios, which
may not be advantageous to the recovery of endangered sea turtle
populations. Currently, the Kemp's ridley sea turtle is the most
endangered sea turtle in the world. Therefore, it is of great importance
to monitor the hatchling sex ratio production in the Kemp's ridley
conservation program. The primary nesting grounds for the Kemp's
ridley is located on a stretch of beach near Rancho Nuevo, Mexico, where
an international conservation effort monitors all nesting and relocates
all nests to protected egg corrals. During several previous nesting
seasons, nest incubation temperatures were monitored within the egg
corrals, and suggested the production of a significant female bias each
season. During the 2001 and 2002 nesting seasons, nest incubation
temperatures were monitored within the egg corrals, and additionally,
within a subset of nests that remained in situ on the natural nesting
beach. The data suggest that a significant female bias was produced
during these nesting seasons in both the egg corrals and in situ nests.
The biased sex ratios predicted during the current study exemplify the
need to monitor hatchling sex ratios produced in sea turtle conservation
programs. Such information is a prerequisite to the development of an
effective management strategy for endangered populations.
Alyssa Geis and Thane Wibbels, Dept. of Biology, Univ. of AL at
Birmingham, Birmingham, AL 35294.