Tournament-Associated Mortality and the Effects of Culling in Wisconsin Black Bass (Micropterus spp.) Tournaments

Abstract

The Wisconsin Cooperative Fishery Research Unit was contracted by the Wisconsin Department of Natural Resources (WDNR) to evaluate mortality associated with culling in bass tournaments. The objectives of this study were to 1) quantify mortality rates of largemouth bass (Micropterus salmoides) (LMB) and smallmouth bass (M. dolomieu) (SMB) occurring as a result of professional black bass tournaments and 2) mortality associated with culling during those tournaments. Among six professional bass tournaments studied, total mortality rates of largemouth bass ranged from 0% to 43.9%, and smallmouth bass from 0% to 55.5% when adjusted for reference fish mortalities. During two simulated tournaments, mortality rates of culled LMB were 0% and 16.0%. Culling in simulated tournaments did not appear to increase mortality rates relative to what was seen at the professional bass tournaments. Our results support other studies that indicate tournament-associated mortality dramatically increases when water temperatures exceed 25°C (especially when largemouth bass virus is present) where largemouth bass are the primary target species and 20°C where smallmouth bass are the primary target species, and that strict regulation of bass tournaments under such conditions may be warranted.