Site fidelity and seasonal habitat preferences of largemouth bass (Micropterus salmoides) in a temperate regulated reservoir

A wide range of fish species navigate and return to previously selected habitats across time scales ranging from days to years. While this ability may be challenged in anthropogenically disturbed systems, such as temperate regulated reservoirs, where littoral freezing/drying may alter critical habitats, no work has yet been conducted to determine if fish within these systems are able to home to specific habitats. In addition, most studies have examined site fidelity over a limited time scale. In this study, we investigated the long-term movement and habitat utilization of largemouth bass Micropterus salmoides (Lacepede, 1802) using a combination of radiotelemetry and habitat mapping across nine consecutive seasons in a winter drawdown reservoir to examine seasonal population- and individual-level spatial clustering and site fidelity. Largemouth bass navigated across large distances through spatially and temporally disturbed habitat with exceptional inter-annual site fidelity during winter, spring, and summer. Drawdown constrained the availability of preferred winter habitat, concentrated fish, and rendered them potentially vulnerable to overexploitation, predation, and competition. Adaptive drawdown protocols should be developed that incorporate temporally and spatially resolved fish movement data, and variables such as available critical habitat, which are essential for maintaining fish population stability in temperate regulated reservoirs.

Automated summary

This study investigated the long-term movement and habitat utilization of largemouth bass, finding that the fish exhibited exceptional inter-annual site fidelity during winter, spring, and summer, navigating across large distances through spatially and temporally disturbed habitat. The study suggests that adaptive drawdown protocols should be developed to maintain fish population stability in temperate regulated reservoirs.