Meeting Abstract

P2.67  Monday, Jan. 5  Whole-body acceleration during swimming in the green sea turtle (Chelonia mydas): A comparison of upstroke and downstroke RIVERA, A.R.V.; BENNETT, N.L.*; RIVERA, G.; WYNEKEN, J.; BLOB, R.W.; Clemson University; Clemson University; Clemson University; Florida Atlantic University; Clemson University arivera@clemson.edu

Sea turtles are distinctive among aquatic turtles in terms of how limb morphology and limb mechanics interact to produce thrust, the force responsible for forward movement during swimming. Sea turtles swim using synchronous, dorsoventral movements of modified forelimbs (i.e., elongated flippers) to propel themselves through water. These patterns resemble the flapping motions of flight and have been hypothesized to produce thrust during both the upstroke and downstroke segments of the limb cycle. However, to date, it is unknown whether both phases of the limb cycle contribute equally to forward propulsion. 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). Maximum whole-body acceleration is considerably higher during downstroke than during upstroke. Additionally, forward displacement of the turtle does not differ significantly between upstroke and downstroke, even though downstroke is significantly shorter in duration than upstroke. 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.