Temporal variation in habitat use by smallmouth bass in the Black River, Arizona.

Abstract

I found significant differences in the use of substrate and cover use by smallmouth bass over 24-hour periods. Juvenile and adult fish used cobble during crepuscular periods and boulders during nocturnal periods. Cover was used less frequently by juvenile and adult fish during crepuscular periods and more frequently by adults during nocturnal periods. I found significant diel and seasonal differences in depth and velocity use by smallmouth bass. Fish typically used faster water during the crepuscular period and slower water during the nocturnal period. In general, fish used shallower and slower water during the fall than the summer. Differential uses of habitats over the diel period may be indicative of predator avoidance strategies or prey availability. Changes in potential habitat area were insignificant within the flow variation tested by PHABSIM. Habitat area available increased with a decreased flow for early life stages and nocturnal habitats.