P3.140 Friday, Jan. 6 Whole-body acceleration and inertial effects of flippers during swimming in the green sea turtle (Chelonia mydas) RIVERA, A.R.V.*; RIVERA, G.; BLOB, R.W.; WYNEKEN, J.; Florida Atlantic University, Boca Raton; Iowa State University, Ames; Clemson University, South Carolina; Florida Atlantic University, Boca Raton firstname.lastname@example.org
Sea turtles swim using synchronous, dorsoventral movements of elongate flipper-shaped forelimbs to propel themselves through water. These patterns resemble the flapping motions of flight and have been shown to produce thrust during both the upstroke and downstroke phases of the limb cycle, although thrust production during upstroke is less than half of that during downstroke. While thrust has been examined, drag and the cumulative effects of drag and thrust on whole-body acceleration during upstroke and downstroke remains unknown. Furthermore, it is unknown if the lower thrust produced during upstroke is able to overcome the effects of drag. To compare the relative contributions of upstroke and downstroke to forward motion in swimming sea turtles, we analyzed high-speed video of rectilinear swimming by juvenile green sea turtles (Chelonia mydas). Our results show that maximum whole-body acceleration is considerably higher during downstroke than during upstroke. In addition, maximum acceleration during upstroke is not significantly greater than zero, thus indicating that positive acceleration is primarily limited to downstroke. These patterns are likely related to the production of greater average and peak accelerations of the flipper during downstroke, which are facilitated by the hypertrophied pectoralis muscles of sea turtles. Finally, we also calculated the acceleration of the true center of mass and used these data to evaluate the inertial effects of flipper motion.