Movements and Feeding Ecology of Immature Green Turtles (Chelonia mydas) in a Florida Lagoon

Abstract

The seasonal and diel movements of 14 green turtles (Chelonia mydas) in Mosquito Lagoon, Florida were monitored using sonic telemetry. The feeding ecology of this population was also studied using dissection and stomach flushing techniques. Immature green turtles made random, long distance movements (x = 8.2 km/day) and occupied deeper waters (x = 1.6 m), apparently not feeding, when water temperatures ranged from 11-18 C; at water temperatures above 25 C they adopted a home range. Turtles were active at temperatures up to 34 C. No diel pattern was evident during winter months, but a definite bimodal pattern was evident at high water temperatures, with green turtles feeding on grass flats in midmorning and midafternoon and moving into deeper waters during the midday hours. Home range area was significantly correlated with body weight but the center of grazing activity was not. Seagrasses made up 88% of the turtles' diet throughout the year.