Largemouth Bass Management in Wisconsin: Intraspecific and Interspecific Implications of Abundance Increases

Abstract

Largemouth Bass (LMB) Micropterus salmoides is one of the most popular sport fish in the United States and is intensively managed across much of its range. Begin - ning in 1989, Wisconsin implemented more restrictive harvest regulations for LMB, including greater minimum length limits, reduced bag limits, and a catch-and-release-only season during the spawning period across much of northern Wisconsin. We tested for trends in LMB relative abundance, growth, and angler catch and harvest in relation to LMB management policies from 1990 to 2011. We also tested for potential sport fish community responses to changes in LMB abundances using Walleye (WAE) Sander vitreus as an example. Angler catch rates and electrofishing catch per unit effort of LMB greater than 8 and 14 in increased significantly statewide. Mean length of age-6 LMB decreased significantly statewide. Release rates of LMB increased from about 80% in 1991 and then plateaued at more than 96% from 2005 to 2011. Concurrent with increases in LMB, adult WAE densities declined in lakes containing LMB. Ongoing research is being conducted to test for interactions between LMB and WAE and to test for additional environmental drivers, such as climate warming, that may be associated with increased LMB abundances. Largemouth Bass abundances have increased in Wisconsin, possibly in response to changes in harvest regulations, angler behavior, and potentially other