Meeting Abstract
Sea turtles embark on extensive transoceanic migrations during early ontogeny, often moving into and out of prevailing currents in search of target food sources. Although efficient swimming is essential to a turtle’s survival, surprisingly little is known about sea turtle swimming capabilities during the critical first year of life. In this study, we examined swimming kinematics of loggerhead sea turtles Caretta caretta through their first year of life, with an emphasis on documenting sustained swimming speed capacity, stability, and flipper motions. Each of four post-hatchling loggerhead sea turtles was placed in a 1000-gallon water tunnel at 3, 4, 5, and 6 months of age and subjected to a stepwise increase in current speed while three high-speed digital video cameras simultaneously recorded their swimming motions. Critical swimming speed ranged from 13 to 20 cm/s for turtles 3-6 months of age. Turtles achieved higher swimming speeds by increasing the frequency, vertical arc angle, and horizontal amplitude of their foreflipper strokes. Body pitch angle decreased with increased swimming speed, but body roll and yaw did not change significantly with increased swimming speed. Recoil motions decreased with ontogeny, suggesting that sea turtles improve their swimming proficiency with age and/or with experience swimming in the water tunnel. No abrupt kinematic shifts indicative of gait transitions were observed across the speed range tested. Our results suggest that young turtles are capable of making gradual adjustments to their flipper motions and body positioning to achieve higher swimming speeds.
