Meeting Abstract

P2.173  Tuesday, Jan. 5  Prey Capture Using Whole Body Fluid Dynamics in Batoids WILGA, C/D*; MAIA, A/RMD; NAUWELAERTS, S; LAUDER, G/V; University of Rhode Island; University Rhode Island; Michigan State University; Harvard University cwilga@uri.edu

Traditionally, suction feeding is described as rapid expansion of the buccal cavity. However, when feeding on the substrate, suction can be generated by lifting the body away from the substrate. This mechanism has been exploited by batoid species, in particular, due to the dorsoventrally flattened body form. Digital particle image velocimetry and high speed video was used to compare the hydrodynamics of feeding behavior in little skates, Leucoraja erinacea and round stingrays Urobatis halleri. We hypothesize that the difference in stiffness of the rostrum and extent of the pectoral fins onto the head between the species should result in behavioral differences; the more flexible rostrum and greater fin area of stingrays will allow more extensive use of body suction. When simulating attached or buried prey, stingrays approach the prey with raised rostral ends of the pectoral fins and then press the edges against the substrate to constrain prey. Stingrays make a tent by raising the rostrum and curling up the pectoral fin edges, then raising the head while rapidly projecting the fins forward and over the prey to generate suction. Skates show a similar behavior, although the smaller fin area does not allow lateral occlusion, thus resulting in weaker flow. Also, skates use a rostral strike behavior that pushes fluid towards the substrate potentially to stun or uncover prey. Thus skates and rays use the body to direct flow in different ways to accomplish similar tasks. This may be explained by the evolutionary divergence in rostral and pectoral fin morphology.