Effect of Low Summer Streamflow on Smallmouth Bass Movements in Crooked Creek

Hodges, S. W. and C. J. Gagen, Fisheries and Wildlife Biology Program, Arkansas Tech University, Russellville, AR 72801

Natural hydrologic conditions cause the surface flow of many streams in the interior highlands to dry extensively during the summer. The objective of this study was to determine how smallmouth bass respond to low summer streamflow in Crooked Creek. Twenty-four smallmouth bass were surgically implanted with radio transmitters in the spring of 1998 and another 27 in the spring of 1999. The fish were tracked through August. The downstream region of the 50-km study section lost surface flow in both years; whereas, the upstream end remained perennial. Fish were captured and released farther downstream in 1999, however, depths at fish locations were similar in both years (mean of 84 cm in 1998 and 93 cm in 1999). Water velocity was also similar at fish locations in 1998 and 1999 (means of 12 cm/s and 17 cm/s, respectively). Fish that were tagged and released in areas prone to drying, moved to avoid being trapped in diminishing pools except one, which was trapped in a pool and died. We also observed that fish captured and released in perennial conditions (N=21) showed little net movement; whereas, those in the drying portion (N=30) moved great distances upstream (mean net movement of 658 m versus 14,700 m, respectively). Substantial downstream movements were associated with rain events that resulted in re-wetting of the downstream reaches. Most of the fish (78.4%) were still swimming in the stream at the end of the study. These data were consistent with the hypothesis that smallmouth bass move to more perennial reaches to increase survival probability in streams that dry extensively.

Copyright © 1999
Texas Chapter of the American Fisheries Society
Last modified: 01/07/09 06:45:17 AM