Unexplained Variation in Movement by Walleye and Sauger after Catch-and-Release Angling Tournaments

Walleye Sander vitreus is a popular species for catch-and-release angling tournaments in North America, but we currently know little about the postrelease behavior of this species and the congeneric Sauger S. canadensis. We used radiotelemetry and acoustic telemetry to track Walleyes (n=101) and Saugers (n=19) for 7d after release at tournaments in Saskatchewan. Our objectives were to provide a description of postrelease movements, and examine the influence of handling variables and stress scores on movement. Walleyes made highly variable movements over 7d, and total dispersal ranged from less than 100m to over 28km from the release point. Path lengthsthe cumulative distance between start and end pointswere considerably longer than straight-line dispersal. Walleyes made larger movements than Saugers, with average total dispersal values of 6.1 +/- 6.9km (mean +/- SD) and 1.3 +/- 1.8km, respectively. Multivariate modeling revealed that species and tournament were the only important factors affecting movement. Fish size (TL), capture depth, distance transported, and time spent in a live well were not consistently important predictors of postrelease movement. Walleyes and Saugers moved much smaller distances when they had poor outcomes for the reflex action mortality predictor (RAMP) test, but RAMP scores in general did not explain a significant proportion of the variance in any fish movement metric. Swim scores at the time of release, an alternative metric of stress, also did not explain a significant proportion of variance in fish movement. Our results show intriguing variance in the behavioral response of individual Walleyes and Saugers to catch and release at tournaments, but do not identify causal factors.