The feeding ecology of the loggerhead sea turtle in the northwestern Gulf of Mexico

The loggerhead (Caretta carerta) is the most common sea turtle in the Gulf of Mexico, yet despite its abundance, little is known about its activities or movements in this portion of its range. The digestive tracts and their contents were collected from 82 sub-adult and adult loggerheads and 6 juvenile loggerheads found stranded on the south Texas coast from 1986 through 1988 to determine where the loggerheads were foraging. Digestive tract contents of subadult and adult loggerheads were analyzed quantitatively by obtaining dry weights of the individual food items. Digestive tract contents of juvenile loggerheads were analyzed qualitatively. Juvenile loggerheads had been feeding at or very near the surface of the water column on Sargassum, zooplankton, pelagic mollusks, and anthropogenic marine debris. Sub-adult and adult loggerheads fed primarily on benthic invertebrates, but on occasion, also fed at the surface, Sea pens (Virgularia presbytes) and crabs were the major food items of the sub-adult and adult loggerheads. Data collected from a research cruise aboard the NOAA ship FERREL in October 1988 indicate that sea pens occur in shallow waters approximately 6 to 12 meters in depth. Crabs eaten by the loggerheads are also concentrated in these shallow waters. These nearshore waters, rich in invertebrates, need to be protected, studied, and managed properly if we are to insure a future for these sea turtles in the northwestern Gulf of Mexico.

The feeding ecology of the loggerhead sea turtle in the northwestern Gulf of Mexico Thesis