Meeting Abstract

80.4  Friday, Jan. 7  Biomechanics of Prey Capture in Elasmobranchs WILGA, C/D*; STOEHR, A/A; DUQUETTE, D/C; ALLEN, R/M; University of Rhode Island; University of Massachusetts Dartmouth; University of New Hampshire; Ross University cwilga@uri.edu

The feeding behavior of sharks and skates is compared to investigate suction and bite mechanisms. Suction flow is generated by rapid expansion of the oropharyngeal cavities to pull prey into the mouth, while bite feeders simply grasp the prey between the jaws. Three species are compared: bamboo sharks are specialized suction feeders; little skates are specialized for grasping; and spiny dogfish are generalist suction and bite feeders. The water flow and movement of oropharyngeal structures was quantified using sonomicrometry and pressure transducers and tested for relationships between kinematic and pressure variables. Bamboo sharks, which have a small change in gape area and a large change in hyoid area, generate the strongest pressures at the fastest rates of change as result of early and rapid rates of change in hyoid and pharyngeal expansion. Skates have a small change in oropharyngeal area and consequently generate the weakest pressure with the slowest rate of change in hyoid and pharyngeal expansion. Dogfish have the largest change in oropharyngeal area and rapid rates of expansion but generates weak pressure due to the longer duration of area expansion and large gape. However, dogfish also have the fastest rate of jaw closure. Bamboo sharks are benthic ambush predators that take prey from complex reef environments where strong suction is an advantage. Skates are also benthic ambush predators that grab prey after trapping it against the substrate with the fins; therefore rapid jaw movements and suction are not crucial. Dogfish use ram to overtake benthic and pelagic prey and thus use a combination of suction and biting for capture.