||Sharks are apex predators that structure marine communities through predation. Despite
a large number of studies in other areas, especially the Pacific, there are no quantitative
data on the diet of tiger sharks, Galeocerdo cuvier, in the northwest Atlantic Ocean
and Gulf of Mexico. Diet was assessed from 169 tiger sharks by life stage, area, and
environmental factors. Fifteen prey groups were identified, with teleosts, molluscs,
birds, cephalopods, and reptiles being the predominant prey categories. There was
an ontogenetic shift in diet, prey size and diversity with an increase in shark size.
Molluscs were most common in smaller sharks, while teleosts and reptiles became more
important in the diet of larger sharks. Dietary overlap was significant by area (Gulf
of Mexico vs Atlantic Ocean) and among all life stages except for young-of-the-year
and adult tiger sharks. Overall, tiger sharks in the northwest Atlantic and Gulf of
Mexico had diverse diets and exhibited ontogenetic shifts, similar to Pacific tiger
sharks. Juvenile tiger sharks also demonstrated selective feeding by targeting gastropod
foot over ingesting the entire animal. The results of this study can contribute to
developing ecosystem models for tiger sharks in an area where their diet has been
studied very little.