DIET, FEEDING-HABITS, AND DIEL FEEDING CHRONOLOGY OF THE BONNETHEAD SHARK, SPHYRNA-TIBURO, IN SOUTHWEST FLORIDA

The diet, feeding habits, and diel feeding chronology of the bonnethea d shark, Sphyrna tiburo, in Tampa Bay and Charlotte Harbor, two estuar ies of southwest Florida, were investigated through analysis of stomac h contents. The diet was very homogeneous and was dominated by crustac eans, consisting mostly of blue crabs, Callinectes sapidus, followed b y seagrasses and traces of mollusks, teleosts, and other material. A s ignificant prey/predator length relationship was found for C. sapidus and S. tiburo. Contingency table analysis and measures of dietary over lap and diet breadth were used to detect seasonal, sex, size, locality , and habitat-related quantitative differences in stomach contents. Re sults suggest that S. tiburo is a specialist that undergoes dietary sh ifts depending on season and habitat. Discontinuity of feeding was inv estigated using two different statistical techniques and results varie d by method, revealing the shortcomings of the most commonly used appr oach and the limited value of considering only stomach contents weight to investigate diel feeding chronology.