Prediction of angler catch rates based on walleye population density

Management of angler harvest of walleyes Stizostedion vitreum assumes that angling catch rates can be regulated by fish densities. Data on walleye densities in northern Wisconsin lakes obtained between 1990 and 1993 were used to develop a predictive model for walleye angling catch rates. Data collected in 1993–1994 were used to validate these models. Total numbers of walleye per acre were estimated from mark-recapture experiments conducted during April and May of each year. Creel surveys were conducted starting on the first Saturday in May and ending on 1 March of the following year for waters where population estimates were made. Linear regression indicated a high correlation between walleye densities and yearly walleye catch rates (r = 0.92, P < 0.05). Using the linear equation generated from this analysis, we predicted yearly walleye catch rates from walleye population estimates in 11 lakes for 1993–1994. All 11 angler catch rates were within the 95% prediction intervals. When data from 1993–1994 were added to the linear predictive model for all lakes, there was no change in the slope. We conclude that total walleye densities are a good predictor of angling catch rates.