MUSSI, M.*; SUMMERS, A. P.; DOMENICI, P.: Gait transition speed, pectoral fin beat frequency, and amplitude in three species of surfperch (Embiotocidae).

The swimming performance of fishes is related to several properties: the body form and surface texture, as well as the size of the animal, fin shape, beat frequency and amplitude of the pectoral fins. These variables have been quantified for three species of Embioticid fishes, Cymatogaster aggregata, Embiotoca lateralis , and Damalichthys vacca. Labriform swimmers show a transition from pectoral fin swimming to caudal fin assisted swimming at higher swimming speeds. The gait transition speed is used to make both scaling and ecological comparisons among these species. Using a flume, several kinematic variables of swimming performance are compared at the gait transition speed. Pectoral fin beat frequency and amplitude across an ontogenetic series of C. aggregata increased linearly with velocity. No significant difference in pectoral fin beat frequency was found among the three species at a particular size. In contrast there were differences in fin beat amplitude among the three species.