Activity patterns of Kemp's ridley turtles, Lepidochelys kempii, in the coastal waters of the Cedar Keys, Florida

Radio and sonic telemetry were used to investigate the tidal orientation, rate of movement (ROM), and surfacing behavior of nine Kemp's ridley turtles, Lepidochelys kempii, tracked east of the Cedar Keys, Florida. The mean of mean turtle bearings on incoming (48 ± 49 0) and falling (232 ± 41 0) tides was significantly oriented to the mean directions of tidal flow (37±9°, P<0.0025, and 234±9 0, P<0.005, respectively). Turtles had a mean ROM of 0.44±0.33 km/h (range: 0.004-1.758 km/h), a mean surface duration of 18± 15 s (range: 1-88 s), and a mean submergence duration of 8.4± 6.4 min (range: 0.2-60.0 min). ROM was negatively correlated with surface and submergence durations and positively correlated with the number of surfacings. Furthermore, ROMs were higher and surface and submergence durations were shorter during the day. Daily activities of turtles were attributed to food acquisition and bioenergetics.