Meeting Abstract

S9-1.4  Jan. 6  Suction feeding mechanics and diversity in fishes WAINWRIGHT, P.C.; Univ. of California, Davis pcwainwright@ucdavis.edu

Suction feeding is the most widely used mechanism of prey capture among fishes, so any attempt to understand trophic diversity in this group must be rooted in an understanding of how suction feeding works. I focus on a series of recent insights on the nature of suction feeding performance and the forces that suction feeders exert on their prey as a foundation for a reinterpretation of some classical axes of trophic diversity in fishes. A model of the musculoskeletal basis of suction pressure points to a set of features that underlie variation in the capacity of fishes to generate suction and therefore provides a framework for interpreting the consequences of diversity in skull form. This work indicates that there are a variety of ways to build a fish that can generate high suction flow velocities. Researchers have focused mostly on drag as the dominant force that suction feeders exert on their prey, but physical modeling indicates that under most conditions the pressure gradient is the dominant force experienced by prey. An insight that emerges here is that the force exerted on a prey item increases with reduction of mouth diameter, even when peak suction velocity is held constant. Mapping of morphology onto prey-use patterns reveals that (1) a few highly demanding prey types tend to generate easily recognized patterns of convergence (e.g. mollusk crushing, zooplanktivory), but (2) most prey types exhibit many-to-one mapping in which multiple forms feed on the same thing. This is partly because the performance requirements of many prey are modest, but also because the complexity of the feeding mechanism means that many morphologies can have the same feeding performance. Supported by NSF IOB-0610310 and 0444554.