
Meeting Abstract
P1.121 Saturday, Jan. 4 15:30 Feeding kinematics and performance of the Hawaiian sleeper, Eleotris sandwicensis (Gobioidei: Eleotridae): modulation between prey species and implications for selective pressures on Hawaiian stream ichthyofauna MAIE, T.*; MEYER, S.; SCHOENFUSS, H.L.; BLOB, R.W.; St. Cloud State University; Clemson University; St. Cloud State University; Clemson University tmaie@g.clemson.edu
A species of piscivorous eleotrid, Eleotris sandwicensis, inhabits lower reaches of streams in the Hawaiian Archipelago, where it feeds on juveniles of native amphidromous gobiid fishes migrating upstream from the ocean. This ambush predator relies on suction to capture its prey. Using high-speed video and geometric modeling we evaluated the kinematics and performance of suction feeding for E. sandwicensis on free swimming gobiid juveniles, comparing performance between successful and unsuccessful strikes, and testing the extent to which E. sandwicensis modulates its predatory behavior between prey species that differ in size, behavior, and muscle physiology. With fast jaw movements as well as a highly expansive buccal cavity, E. sandwicensis achieves high performance that enables the capture of elusive prey. Our analyses indicated that the species with larger juveniles (S. stimpsoni) could be captured from up to 18.6% body length (BL) of the predator away from the mouth, but capture of the smaller species (A. guamensis) required a closer distance (12.2% BL). Predator-prey distance appears to be the predominant factor determining strike outcome during feeding on juvenile A. guamensis. However, during feeding on juvenile S. stimpsoni, E. sandwicensis demonstrates a capacity to modulate strike behavior. The ability of E. sandwicensis to capture larger prey fish from longer distances suggests a potential biomechanical basis underlying observations that predation by eleotrids imposes selection against large body size in juvenile gobies. NSF-IOS 0817911, 0817794.