Reservoir Striped Bass Movements and Site Fidelity in Relation to Seasonal Patterns in Habitat Quality

Abstract

Adult striped bass Morone saxatilis perform best when water temperatures are below 26°C and dissolved oxygen levels are above 2 mg/L and will begin to exhibit stress responses at higher temperatures or lower oxygen levels. In southern U.S. reservoirs, summer conditions may result in a reduction of suitable habitat for adult striped bass and therefore influence population dynamics and distribution. We tracked 51 adult striped bass that had been implanted with individually coded sonic transmitters for 2 years in Lake Gaston, Virginia−North Carolina, to determine the impact of habitat availability on seasonal trends in movement and distribution. Monthly movement rates of individual fish averaged 7,340 m (SE = 544 m) over the course of the study, and no significant differences in movement rates were detected among seasons or between sexes. Striped bass were relocated throughout the reservoir in all seasons despite evidence of spatial variability in the availability of suitable habitat during the summer months. Individual striped bass tended to occupy specific reservoir areas in all seasons and years of the study, with the exception of spring spawning runs. Home ranges of individual fish were not clearly related to the availability of summer habitat refuges but tended to be located in large, downlake basins or near the tailrace of an upstream dam. Fidelity of striped bass to limited areas within the reservoir suggests that spatially explicit management strategies are appropriate for reservoir populations of striped bass.