Influence of Environmental and Biological Factors on the Space Use and Movement Behavior of Juvenile Caribbean Green Sea Turtles

Understanding the movement ecology of a species can provide valuable insight into responses to environmental change and inform management and conservation decision-making. Using acoustic telemetry, we tracked eight juvenile Green Sea Turtles (Chelonia mydas; curved carapace length, 50.59 ± 4.71 cm [42.8-57.9 cm], mean ± SD [range]) between July 2015 and December 2016 in Brewers Bay on St. Thomas, United States Virgin Islands, and characterized their movements - specifically area use, diving behavior, and rates of movement. We investigated how these movements were influenced by diel period, water temperature, barometric pressure, and wind speed. We found that the diel period significantly influenced space use, with turtles displaying behaviors typical to the species (i.e., resting at night and foraging during the day); however, the turtles in this study occupied relatively shallow habitats at night compared with turtles in other studies. Turtles showed strong fidelity to resting and foraging areas, consistently shuttling back and forth between the same areas diurnally, with one individual relying on the same resting area across the full 1.5-yr study. Warmer water temperatures were associated with shorter dive durations and higher rates of movement. Movement behaviors also shifted in response to indicators of storm activity (barometric pressure and wind speed), with turtles tending to dive deeper and for longer durations. Our results indicate that although some behavioral responses are consistent across Green Sea Turtles, others display plasticity, suggesting the management of this species in the face of increasing anthropogenic interactions must take into consideration local conditions.