Diving behavior of immature hawksbill turtles (Eretmochelys imbricata) in a caribbean reef habitat

Abstract

Time-depth recorders were deployed on immature hawksbill turtles at the southwestern reefs of Mona Island, Puerto Rico, to examine patterns of diving behavior. Diving profiles of 10-12 day duration were obtained from five turtles ranging in carapace length from 27-52 cm. Turtles exhibited contrasting diurnal and nocturnal diving behaviors. During daylight hours, dives were made 92% of the time, featured continuous depth variation and were attributed to foraging activity. Foraging dive duration increased with turtle size; individual mean dive durations ranged from 19-26 min; mean post-dive surface intervals ranged from 37-64s; mean depths ranged from 8-10 m. At night, dives were made 86% of the time to constant depths and were interpreted as resting behavior. Resting dive durations were not dependent on turtle size; individual mean dive durations ranged from 35-47 min; mean post-dive surface intervals ranged from 36-60s; and mean depths from 7-10m. Immature hawksbill turtles maintained short term home ranges several hundred meters in extension.