Predicted Effects of Angler Harvest On Largemouth Bass Abundance in Wisconsin Lakes

Abundance of largemouth bass Micropterus salmoides has increased in many northern lakes and this trend is likely to continue based on projected changes in climate.  The potential for largemouth bass interactions with other game fish such as walleyes Sander vitreus and density-dependent effects on bass growth and size structure are causes for concern among anglers and biologists.  In an attempt to reduce largemouth bass abundance, the minimum length limit for bass has been removed from some northern Wisconsin lakes, but low rates of exploitation may prevent significant reductions in abundance.  Our objectives are to use age-structured models to determine if angler harvest can be used to reduce largemouth bass abundance and recruitment potential in northern Wisconsin lakes and if length-based harvest regulations can be modified to facilitate these reductions.  We expect that a large proportion of the largemouth bass population will need to be removed to decrease abundance and recruitment potential, and we expect that relatively liberal harvest regulations (i.e., no minimum length limit) will be more likely to achieve these reductions.