Meeting Abstract
Braking ability in fishes is an important indicator of their ability to maneuver, evade predators, and colonize new habitats, especially across environmental gradients. Sculpins (Scorpaeniformes: Cottoidea) are a diverse group of benthic fishes ranging from subtidal to high intertidal habitats. The sculpin species living within and across these environments exhibit high morphological variation, especially in their pectoral fins. However, the functional implications of this interspecific variation have not been investigated. We measured the pectoral fin movements during braking of three sculpin species that come from different habitats and vary in fin morphology. We calculated the instantaneous change in fin angle and fin area as indicators of drag production, while changes in whole-animal velocity represented braking performance. Preliminary results suggest that the high intertidal species, Oligocottus maculosus, incorporated more fin area during braking and abducts the fin at greater angles, resulting in greater deceleration compared to the subtidal species. Additionally, full-fin passive-bending tests were used to determine the in situ stiffness of the fin rays for O. maculosus and one of the subtidal species, Leptocottus armatus. Preliminary observations suggest that the fin is mechanically regionalized in O. maculosus (that is, the rays show different degrees of resistance to bending), and L. armatus appears to have greater resistance to bending overall. High-intertidal sculpin species may perform better at braking and have regionalization of fin mechanical properties that allow them to inhabit highly complex tidal zones. Ongoing analyses of sculpin pectoral fin kinematics and their mechanical properties will provide insight into how ecology, behavior, morphology, and mechanical properties change along environmental gradients.
