Meeting Abstract

27.2  Monday, Jan. 4  Swimming and Early Diving Behavior by Juvenile Flatback Sea Turtles (Natator depressus) WYNEKEN, J*; SALMON, M; HAMANN, M; Florida Atlantic Univ.; Florida Atlantic Univ.; James Cook Univ. jwyneken@fau.edu

Flatback sea turtles lack an oceanic phase in their early life history. Instead, the turtles grow to maturity in shallow turbid shelf waters of tropical Australia. We compared (i) frenzy and postfrenzy swimming to migratory swimming in species with an oceanic stage and (ii) diving behavior development in the neonate flatbacks. Swimming data were obtained from hatchling turtles. We speculated that the risk of predation selected for the flatback activity patterns that decline little. During 4 days of observations, nocturnal flatback activity declined little compared with other sea turtle hatchlings that migrate into the open ocean. Diurnal activity was similar in all species. Dive data were collected from 1 – 7 wks old turtles during 30 min trials in shallow (9-12 m) turbid waters near Townsville, QLD, Australia. A total of 194 dives (21 turtles) was recorded. Most were short and shallow; yet even at 4-weeks old flatbacks could dive to the bottom. We compared dives among species to identify behavioral differences in flatback dive development from leatherbacks (Dermochelys coriacea) and green turtles (Chelonia mydas) that at the same age, live in clear, deep oceanic waters . Most flatback dives had V- or W-profiles whereas most leatherbacks dives had V-profiles, while in green turtles, dives had V- or U-profiles. Flatbacks, unlike the other species did not dive deeper or longer as they grew older. Most flatback swam slowly during dives (like leatherbacks) but in some cases flatbacks swam much faster than green turtles. Flatbacks could dive repeatedly with just a brief pause at the surface to breathe. We speculate that flatback diving form, in their murky habitats, enables: (i) efficient searching for prey thru the water column, (ii) minimizes surface time allowing return to previously attractive locations, and (iii) rapid escape from predators.