Evaluation of Biological Performance Indicators for Monitoring Exploitation of Walleye Populations in Northern Wisconsin

We determined if variation in biological performance indicators (i.e., ω, mean total length (TL) at age 3, mean age at 50 cm TL, age classes present, age class diversity [H], catch-per-effort [CPE] of age-0 walleyes, coefficient of variation [CV] in age-0 CPE, targeting angler catch rate, and the mean TL of the 10 smallest mature females) observed for walleye populations in northern Wisconsin could be explained by exploitation while also considering adult density, lake surface area, recruitment category (naturally-reproducing or stocked), latitude, and longitude as explanatory variables.  We also determined if BPIs could be used to identify walleye populations that have experienced relatively high exploitation rates. Exploitation was of little importance in explaining observed variation in BPIs and BPIs were not effective in identifying walleye populations with relatively high mean exploitation rates. Biological performance indicators may be effective for assessing changes in exploitation within individual populations, but may be ineffective at a broad spatial scale because relatively high or low BPI values observed for some populations may be the result of factors other than exploitation. Ongoing analyses will evaluate BPIs in relation to exploitation using data for populations where relatively frequent estimation of exploitation has occurred.