Effects of Hunger on Foraging Behavior of Age-0 Smallmouth Bass in a Heterogeneous Environment

Abstract

We examined how hunger affected habitat use by juvenile smallmouth bass, Micropterus dolomieu, as they moved among a variety of habitat patches. Hungry and satiated fish were placed in an artificial stream that contained three types of habitat patches: pools with uniform depth and low water velocities, mazes with uniform depth and moderate water velocities, and riffle-pool complexes with varying depth and the highest water velocities. Food was only available in the riffle-pool complexes. Hungry fish spent more time in the riffle-pool complex than satiated fish did. However, hungry and satiated fish did not differ in the time it took to exit the pool they were initially placed in, the number of patches entered, or the number of times they moved among patches. Both hungry and satiated fish frequently entered other patches after foraging successfully in the riffle-pool complexes. There was wide variation in foraging behavior among individuals in both treatment groups, and we consistently observed individuals that did not alter their foraging behavior in response to the difference in food availability among patches.