Meeting Abstract

P3.115  Saturday, Jan. 5  Predicting Habitat Associations from the Pectoral and Caudal Fin Aspect Ratios of Surfperches (Embiotocidae) PERLMAN, Benjamin M.; Moss Landing Marine Laboratories bperlman@mlml.calstate.edu

It has been suggested that the dynamics of different swimming modes of fishes may constrain their ecology. Two labriform modes used by embiotocids are flapping and rowing. Flapping has a dorso-ventral thrust generation as rowing is in the antero-posterior direction. Extrapolating from the literature, we expect that flappers have a high fin aspect ratio whereas rowers have low aspect ratios. This study was conducted to determine if morphological aspects of the pectoral and caudal fins of embiotocids were correlated with habitat associations. We used 19 species of embiotocids with three replicates per species and placed them into 7 different habitat types, ranging from calm to high wave-swept areas, chosen based upon literature describing where the 19 species are primarily found. Angle of the fin base with the long axis of the body was measured to infer flapping versus rowing. The aspect ratios were calculated by measuring the length and surface area of the fins (L²/SA) using the Image J program. Only flat fins on the left side of the body of preserved specimens were used. Pectoral fin aspect ratio was negatively correlated with the fin base angle, as expected. The pectoral fin aspect ratio was positively correlated with habitat when ordered from calmer to more wave-swept areas. Caudal fin aspect ratio was much more variable. Closely related species tended to group together, suggesting a phylogenetic reason for fin shape. However, there were outliers which we hypothesize exist because species can change how they use their fins, making morphology alone a poor predictor of function.