Meeting Abstract

75.1  Sunday, Jan. 6  The effects of variation in snout length on prey capture kinematics in pipefish. ROOS, G*; VAN WASSENBERGH, S; HERREL, A; ADRIAENS, D; AERTS, P; Univ. Antwerpen, Belgium; Univ. Antwerpen, Belgium; Univ. Antwerpen, Belgium; Ghent Univ., Belgium; Univ. Antwerpen, Belgium gert.roos@ua.ac.be

The cranium of syngnathid fish (seahorses, pipefish and seadragons) is characterised by an elongated snout with minute jaws at its end. Previous studies have shown that their feeding strike consists of an extremely rapid retraction of the hyoid accompanied by an equally rapid upward rotation of the head. The fact that prey capture times of less than 6 ms have been recorded, makes them one of the fastest suction feeding vertebrates. A recent diet analysis of Australian syngnathids showed that species with relatively long snouts consume far more mobile prey than species with relatively short snouts. However, the functional basis of this difference in prey choice is unknown. We hypothesize that the mouth of long snouted syngnathids can reach the prey at higher velocities, thereby minimizing the chance of prey escape. An alternate hypothesis states that syngnathids with longer snouts are able to suck in a greater amount of water than short snouted individuals, therefore creating a faster water flow towards the mouth. Here, both hypotheses are tested by comparing the kinematics of prey capture in pipefish differing in snout length using high-speed video recordings (2000 Hz). We selected pipefish species which snouts ranging in length from 50% to almost 70% of the total head length. Our results indicate that the velocity of the snout tip, as well as buccal expansion magnitude increases for pipefish species with relatively longer snouts. However, species with relatively shorter snouts reach peak velocity of the tip of the snout in less time combined with a shorter prey capture time than species with relatively longer snouts.