DEVRIES, M.S.*; WAINWRIGHT, P.C.; Univ. of California, Berkeley; Univ. of California, Davis: The effects of acute temperature change on prey capture kinematics in Largemouth bass, Micropterus salmoides

A common relationship in ectothermic vertebrates is that as temperature decreases, the rate of muscle contraction decreases. Animals moving in cooler water must also contend with the increasing viscosity of their medium which occurs with decreasing temperature. We examined the effects of acute temperature changes on prey capture kinematics in Largemouth Bass, Micropterus salmoides expecting a considerable influence, given the dual effects of temperature on muscle performance and water viscosity. We acclimated five individuals to 22&degC and then acutely exposed them to 15&degC, 20&degC, 25&degC and 30&degC. We video-recorded feeding events at each temperature at 500 frames s-1. Although we found a significant overall effect of temperature on the time taken by M. salmoides to open the mouth during prey capture the Q10 value between 15-25&degC was only 1.28, well below the minimum expected value 2.0. Thus, we suggest the possibility that M. salmoides recruit additional motor units at lower temperatures in order to partially compensate for the effects of acute temperature change. The capacity of M. salmoides to mitigate the impact of acute temperature change on muscle physiology and the physical properties of water may represent an adaptation to a predatory lifestyle in a thermally variable environment.