FRANCIS, JR., A.W.*; TURINGAN, R.G.: Functional implications of asymmetrical feeding biomechanics in pleuronectiform fishes

Flatfishes (Order Pleuronectiformes) differ from the generalized teleost morphology in that bilaterally symmetrical larvae metamorphose into bilaterally asymmetrical juveniles where one eye migrates to the opposite side of the head. The development of morphological asymmetry is expected to have profound consequences for flatfish feeding biomechanics, performance, and ecology. Biomechanical features associated with feeding in developing summer flounder, Paralichthys dentatus, were measured for both ocular (left) and blind (right) sides. Using principles from mechanical engineering, the measurement of lever arms responsible for lower jaw depression and elevation allowed for the determination of mechanical advantage for each side of the head. Mechanical advantage was then used to make functional predictions about feeding mode where the oral jaw lever system in fishes represents a compromise between speed of jaw movement and strength of bite. Analysis of variance or analysis of covariance revealed significant differences in lever arms and mechanical advantage between sides of the head of late metamorphic and early juvenile summer flounder. In particular, the ocular side is predicted to have a faster bite while the blind side is predicted to have a stronger bite. Work currently in progress will test predicted functional asymmetry using high speed recordings of feeding kinematics in developing flatfish.