Microhabitat preferences of longear sunfish: low light intensity versus submerged cover

Abstract

Both cover and light intensity are important factors in microhabitat selection of fishes, suggesting a possible hierarchical relationship. Many centrarchids have been shown to prefer low light intensities and heavy submerged cover, but adult nonbreeding longear sunfish are reported to occupy sparsely vegetated, clear, shallow water during the brightest part of the day, probably for foraging. To determine the relative importance of cover and light intensity to longear sunfish, we presented nonbreeding adults with choices between these two conditions in a series of three laboratory experiments. Longear sunfish preferred low light to high light intensity and preferred submerged cover to no cover. However, when given a choice, they preferred to occupy low light intensity conditions without cover rather than submerged cover under higher light intensity conditions. Thus, low light intensity, such as is found in greater pool depths, may be the preferred refuge from predation for longear sunfish.