An Evaluation On The Effects Of Angling And Vegetation On Largemouth Bass Spawning Success And Recruitment In Illinois Impoundments
Michael J. Mounce, Natural Resource Specialist, Illinois Department of Natural Resources, 1660 West Polk Avenue, Charleston, IL 61920; (217) 345-2420; FAX (217) 348-5873; mmounce@dnrmail.state.il.us
Recent studies have suggested that angling male black bass Micropterus spp. during spawning activities has a negative impact on spawning success. Recommendations have been made to consider limiting angling of largemouth and smallmouth bass during their spawning or parental period. Although the spawning success of individual black bass could be impacted by anglers, does angling have an impact at the population level and/or is habitat availability equally or more important? To evaluate these questions, district fisheries managers with the Illinois Department of Natural Resources (IDNR) were asked to submit a list of lakes which have been creel recently and which have < 5% or > 35% of the shoreline covered in submersed vegetation. IDNR creel data, IDNR division of fisheries fall standardized biological survey data, and vegetation characterizations and coverage area estimates by IDNR biologists were used to evaluate potential effects of angling and vegetation abundance on largemouth bass spawning success and recruitment at the population level on 17 lakes located throughout Illinois. Catch per unit effort (CPUE) of young-of-the-year (YOY) largemouth bass and young-adult ratio (YAR) were significantly greater and relative weight (Wr) of bass > age 1+ significantly lower in lakes with higher levels of vegetation. Positive correlations were found between total fishing pressure and CPUE of YOY largemouth bass and YAR. Positive correlations were also found between adjusted bass fishing pressure and CPUE of YOY largemouth bass. These analyses suggest that vegetative habitat may have a greater role in largemouth bass spawning success and potential recruitment at the population level than angling.