Status and trends of black bass fisheries in Wisconsin: Regulation (in)effectiveness?

ABSTRACT Objective Fisheries-dependent and fisheries-independent information is critical for assessing the status and trends of fish populations and regulations. We tested for changes in common fisheries-dependent and fisheries-independent metrics for Largemouth Bass Micropterus nigricans (LMB) and Smallmouth Bass M. dolomieu (SMB) in Wisconsin during 1990–2024. We also tested for responses associated with liberalized harvest regulations compared with a more conservative bass regulation. Methods We used creel survey data collected during 1990–2024 to test for trends in fisheries-dependent metrics. We used electrofishing data to test for trends in fisheries-independent metrics. Electrofishing data were also used to test for differences in relative abundance and proportional size distribution in a subset of bass populations with liberalized harvest regulations versus a more conservative black bass regulation. Results Directed angler effort for SMB significantly increased, whereas directed effort for LMB did not change. Catch rates for both species significantly increased. Harvest rates for LMB remained low, while SMB harvest rates significantly declined. Relative abundances for both species significantly increased. Population size structure increased for low to intermediate length-classes of LMB and intermediate to high length-classes of SMB. Density-dependent growth responses in mean length at age were evident in older age-classes for both species. Relative abundances of LMB populations with liberalized harvest regulations significantly declined, whereas SMB showed no change. Both species showed increased population size structure, but the increase was greater for LMB. Conclusions Our results suggest that bass populations are thriving in Wisconsin. However, density-dependent effects on growth may not be balancing diverse angler desires of catch and trophy potential or alleviating the negative correlation of LMB with Walleye Sander vitreus. Liberalized regulations on LMB showed promise for better balance in diverse bass fishing opportunity. Whether future angler behavioral responses (e.g., harvest rates) will be sufficient to balance fish communities that are managed for multiple species and ecosystem services is unclear.