Meeting Abstract

S5-6   11:30 - 12:00  Locomotor challenge of waterfall-climbing gobies in the wake of transition between media Maie, T; University of Lynchburg, Lynchburg, VA maie.t@lynchburg.edu

An amphidromous goby, Sicyopterus japonicus, migrates from the ocean to upstream regions of many streams and rivers in the pacific coasts of Japan and Taiwan in spring and summer. Using its mouth and fused pelvic fins (pelvic sucker) that exert suction-based adhesion, this gobiid species exhibits an inching climbing behavior and surmount waterfalls, which physically disrupt movements of inhabitants, including its competitors and predators. When emerging from the aqueous environment to commence such locomotor endeavor, change in the effective density (lack of buoyancy) in such transition substantially increases the force requirement for adhesion, and consequently the fish must exert adhesive suction strong enough to support its own body weight against gravity on the rock surface. With several experimental scenarios that this waterfall-climbing fish would frequently encounter during climbing, how suction force and some aspects of climbing performance, such as endurance and kinematics, by the pelvic sucker scale in relation to body size were evaluated. The pattern of the adhesive performance reflects changes in functional demands placed on the locomotor structure and mechanics during which a transition of the surrounding medium is made, including linear increase in safety factor and non-linear change in endurance in sustained adhesion through ontogeny.