Meeting Abstract

80.6  Friday, Jan. 7  Prey Processing in Elasmobranchs STOEHR, A/A*; WILGA, C/D; ALLEN, R/M; Univ. of Massachusetts, Dartmouth; Univ. of Rhode Island; Ross University astoehr@umassd.edu

Despite many recent studies focusing on capture in fishes, post-capture behavior remains relatively unexplored. It is unknown if the mechanics of prey processing, an integral component of the feeding process, differs between suction and bite events, processing and capture behaviors, and between species with different cranial morphologies. The kinematics of the jaws, hyoid, and 2nd branchial arches were quantified by sonomicrometry and pressure transducers during prey processing in bamboo sharks, Chiloscyllium plagiosum, spiny dogfish, Squalus acanthias, and little skates, Leucoraja erinacea. Similar to suction and bite prey capture mechanics, buccal, hyoid, and pharyngeal cavity expansions generated subambient pressures during suction processing, while gape, hyoid, and pharyngeal compressions created superambient pressures during bite processing in all species. In contrast to capture, during processing cavity movement and peak pressure do not progress anteriorly to posteriorly. Generally, bite processing events were longer than suction processing events. The mechanism of cavity expansion and compression also differed between species and behaviors, with hyoid and pharyngeal width variably increasing or decreasing. The directional movement of the arches appears to depend on hyomandibular orientation and coupling. Bamboo sharks, which possess a lateral hyoid arch typical of suction capture specialists, also generated the greatest suction pressures during processing. Bamboo sharks are more stereotyped in their mechanisms compared to the dogfish and skates, which are generalist predators. Thus, differences during prey processing may reflect different degrees of cranial kinesis and morphological constraint among the elasmobranchs.