Tournament and non-tournament anglers have little effect on a largemouth bass population compared to natural mortality

Popularity of bass Micropterus spp. catch and release and tournament angling during the past decade has resulted in increased potential for these activities to induce population level effects. Understanding capture rates and mortality sources relative to total population mortality is essential to focus of management. We conducted monthly electrofishing, solicited nontournament angler tag returns, and censused largemouth bass Micropterus salmoides tournaments at Brushy Creek Lake, IA, USA from April 2015 to June 2018. We used a multistate mark-recapture model to evaluate the effects of air temperature, water temperature, tournament bass per angler, and tournament initial mortality on non-tournament and tournament angler capture probability and natural, non-tournament angling, and initial and delayed tournament mortality. Average total annual mortality was 0.66 with natural mortality representing the largest mortality source (0.57) followed by delayed tournament mortality (0.06), non-tournament angling mortality (0.02), and initial tournament mortality (0.006). Our results reveal both non-tournament and tournament angling mortality are low compared to natural mortality in some lakes. Therefore, cumulative angling mortality likely has minimal population level effects on some bass populations