Movement and habitat selection patterns of smallmouth bass Micropterus dolomieu in an Ozark river

Abstract

Limited information exists on 24-hr movement and habitat selection patterns of stream dwelling smallmouth bass, Micropterus dolomieu. We monitored the 24-hr movement patterns of smallmouth bass in an Ozark river during three seasons: summer, autumn, and winter. During each season, fish were located every two hours throughout a 24-hr period; habitat data and water depth were collected at each fish location. Four random points representing available locations around each fish location were generated in ArcGIS. Habitat and depth data were collected at each of these points, and discrete choice models were fit to the data to predict habitat and depth selection by smallmouth bass. No significant differences in movement across seasons or time of day were evident, although the greatest observed displacement within a 2-hr tracking period occurred during the winter, with one bass moving over 630 m. Across all three seasons, water depth and habitat type were strong predictors of bass locations. Throughout our study, water depths used by smallmouth bass ranged from 0.6 to 3.7 m. Although depth of water used by fish did not differ by time of day, fish used the deeper waters of Big Spring during the winter and intermediate depths during the summer and autumn. Smallmouth bass utilized several habitat types; however, bass selected boulders more frequently in all seasons than any other available habitat type. Our work provides additional insight into smallmouth bass behavior that will help guide future management.