Movement and habitat use by stream-dwelling smallmouth bass
habitat, bass, activity, pool, upstream, night, Substrate
Journal or Book Title
Transactions of the American Fisheries Society
We monitored the movement and habitat use of 34 stream-dwelling smallmouth bass(Micropterus dolomieui) in Jacks Fork River, Missouri, by radiotelemetry. Observations weremade 24 h/d in all seasons. Definite patterns of diel activity and habitat use were evident andwere modified by seasonal changes in water temperature. Fish remained in restricted homeranges for most of the year but tended to disperse in spring when all of the radio-tagged fish lefttheir home pool; 75% returned during the same season. Equal numbers of fish moved upstreamand downstream. However, the median distance moved upstream was greater. Intrapoolmovement of smallmouth bass peaked soon after sunrise and again after sunset in all seasons.Average intrapool movement was 120 m/d when water temperatures were lowest (4°C) and 980m/d when temperatures were highest (27.5°C). In the warmer seasons, fish preferred logjamsand root wads by day and increased their use of boulders at night. In cooler seasons, fish usedboulders almost exclusively. Regardless of season, open water without cover was used mostduring the period just after sunrise but was never used in proportion to its availability. Boulderswere the most preferred substrate, and gravel was the least preferred. Small mouth bass usedintermediate depths the most and showed no daily or seasonal changes in depth preferences.Fish preferred velocities less than 0.2 m/s at all times of day and in all seasons. Movements infloods did not differ from those observed during normal discharges; however, single logs wereselected in significantly greater proportion than logjams.