Meeting Abstract

P3.70  Thursday, Jan. 6  Functional Morphology of Northern Clingfish Feeding on Limpets WAINWRIGHT, D/K; Duke University dylan.wainwright@gmail.com

Although the northern clingfish, Gobiesox maeandricus, rarely grows over 16cm in length, it is able to consistently capture limpets as a part of its diet. The purpose of this study was to determine how this small fish dislodges and captures such a well-defended prey. Clingfish exhibited a novel prying behavior to dislodge limpets using anteriorly oriented dentary teeth to lever limpets off the substrate before quickly capturing them with a suction strike. Using a micro-catheter pressure transducer, pressure readings were taken under limpets during fish feeding; these readings indicated that the limpets were not sticking to the substrate at their full capacity when successfully captured by the fish. Video data suggest that the fish attempted to surprise the limpets to take advantage of the lower tenacities limpets produce when they are moving on the substrate. The sucker disc of the clingfish is active during feeding events, providing the fish with a fulcrum for prying and also ensuring that the fish does not move backward. Peak fluid velocities during suction feeding events were estimated at between 1.46m/s and 4.64m/s with a positive trend when plotted with fish size; these values are high compared to known fluid velocities for other species of fish. High-speed video showed that by limiting gape and decreasing their distance to the prey item, these fish are able to expose limpets to high fluid velocities and accelerations during feeding events. Thus, limpets were usually captured by first prying them from the substrate and then quickly sucked into the mouth of the clingfish. The prominent role of the cling during feeding indicates that this locomotor innovation may also have keyed a trophic niche expansion in this group of fishes.