Habitat Use, Home Range, and Movement of Shoal Bass in Alabama

Abstract

The shoal bass Micropterus cataractae has been listed as a species of special conservation concern by the American Fisheries Society and the Alabama Department of Conservation and Natural Resources. We describe seasonal movement, habitat use, and home range of 23 shoal bass fitted with radiotelemetry transmitters in Little Uchee Creek, Alabama. During this tracking period, the region experienced a drought that probably influenced shoal bass habitat choice and movement during reduced streamflow. During most of the year, shoal bass preferred runs and eddies, low current velocity (≤0.30 m/s), moderate depth (0.4–0.8 m), and boulder and bedrock substrates. Most shoal bass in Little Uchee Creek had a strong affinity for shoal habitat. Generally, movement was minimal (<7 m/week); the fish exhibited relatively sedentary behavior and remained within the shoal complex. Home ranges were small and averaged 0.11 ha (50% kernel home range) and 0.47 ha (95% kernel home range); typically, these fish inhabited less than 30% of the 1.15-km-long study area. As streamflow decreased during late summer and fall 2006 and dewatered the shoal, some shoal bass migrated to a nearby deepwater pool (>1.2 m deep) that contained sand bottom and had a water velocity of zero. However, 87% of the radio-tagged shoal bass did not emigrate from the shoal habitat as it became dewatered; these fish subsequently perished. Small home ranges and the lack of movement by many shoal bass from the dewatered shoal habitat to deepwater pool refuges warrant concern to ensure that adequate water quantity is maintained in streams where these fish are found.