Habitat Selection by Smallmouth Bass in Response to Physical Characteristics of a Simulated Stream

Abstract

Juvenile (14-16 cm total length) and adult (24-26 cm) smallmouth bass Micropterus\ndolomieui were studied in a laboratory stream tank to determine the influence of light, current velocity, substrate, and cover on habitat selection. These factors were varied singly and in combination\nfor ranges of 30-4,000 lx light intensity; 1-47 and 0-20 cm/s current; substrates of sand\n(1 mm), gravel( 15-40 mm), boulders with cobble filler (250 mm with 50-100 mm), and boulders with cobble removed; and three types of clear and opaque covers. Fish exhibited strong preferences for slow current (< 10 cm/s), low light (<300 lx), and cover that provided slow current and low\nlight. Substrate was only important when fish could get into the interstices. Juveniles selected slightly slower current speeds and lower light intensities than adults, but were similar in all other\nrespects.