Swimming performance of walleye (Stizostedion vitreum)

Swimming performance of walleye (Stizostedion vitreum) from a wild populati on 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 a nd culverts. Ucrit(60) (the highest speed maintainable for 60 min) values r anged from 0.30 to 0.73 m/s and increased significantly with length and tem perature. Ucrit(10) (the highest speed maintainable for 10 min) values rang ed 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 sp eeds (1.60-2.60 m/s) during short (temperature-independent) bursts of swimm ing activity. The relatively low Ucrit(60) values suggest that walleye poss ess a narrow scope for aerobic activity compared with other species, which may account for their poor performance in fishways. However, the small diff erences between Ucrit(60) and Ucrit(10) values and the large differences be tween Ucrit(10) and fast-start performance suggest that low passage efficie ncy may be caused by a behavioural disinclination to switch from low to hig h intensity activity.