Ontogenetic changes in the flipper-beating behavior in free-range versus tank-housed green turtle (Chelonia mydas) juveniles

Recently, acceleration data loggers have been used to quantify the flipper (or wing) beating behavior of free-ranging aquatic animals, and this has contributed to our understanding of the swimming activity of marine life. By using acceleration data loggers, we quantitatively evaluated the difference in flipper beat frequency of juvenile green turtles at sea and in tanks for four different stages of growth. The results indicated that juveniles about two weeks old after emergence exhibited significantly higher swimming activity at sea than in the tank; this may help them to reach the oceanic gyre habitat. Juveniles gradually decreased their activity enhancement at sea after their peak, at two weeks old, through the next two months before finally leveling-off. This may reflect their adaptation of passive drifting using the ocean currents. This is the first intensive study that shows the flipper beating behavior of juveniles at sea, and it reveals that ontogenetic changes in this activity are more pronounced at sea, indicating the importance of field observations for understanding the dispersal of sea turtle juveniles