Swimming performance of walleye (Stizostedion vitreum)

Abstract

Swimming performance of walleye (Stizostedion vitreum) from a wild population was measured relative to fork length (0.18-0.67 m) and water temperature (5.8-20.5°C), to provide models for setting water velocities in fishways and culverts. Ucrit60(the highest speed maintainable for 60 min) values ranged from 0.30 to 0.73 m/s and increased significantly with length and temperature. Ucrit10(the highest speed maintainable for 10 min) values ranged from 0.43 to 1.14 m/s and also increased significantly with fish length and water temperature. When startled, walleye were able to attain higher speeds (1.60-2.60 m/s) during short (temperature-independent) bursts of swimming activity. The relatively low Ucrit60values suggest that walleye possess a narrow scope for aerobic activity compared with other species, which may account for their poor performance in fishways. However, the small differences between Ucrit60and Ucrit10values and the large differences between Ucrit10and fast-start performance suggest that low passage efficiency may be caused by a behavioural disinclination to switch from low to high intensity activity.