Balancing Fisheries Management and Water Uses for Impounded River Systems

Using Available Prey Estimates to Inform Largemouth Bass Stocking Strategies

Mark W. Rogers and Micheal S. Allen

doi: https://doi.org/10.47886/9781934874066.ch24

Abstract.—Growth and survival of stocked fish are positively influenced by the availability of suitably sized prey fish. We examined relationships among juvenile largemouth bass Micropterus salmoides size structure, occurrence of piscivory, and biomass relative to fish prey size structure and biomass across Florida’s latitudinal gradient to evaluate potential fish prey availability across a broad spatial scale of lakes. We sampled the 2003 and 2004 largemouth bass year-classes and potential fish prey in April/May (i.e., spring) and in June/July (i.e., summer) in six study lakes distributed from northern to southern Florida. Available prey to predator ratios (AP:P) decreased with increased fish size but indicated that prey resources were not limiting at any lake during either year (all AP:P > 8). We used a biomass-based food web model for our lake with the lowest AP:P we measured (~9) to determine if bioenergetics-based predictions agreed with AP:P metric indications of the system’s potential to support a higher standing crop of largemouth bass. Food web simulations showed potential to increase the standing crop of adult largemouth bass population by up to 30% at high stocking rates (i.e., 150 fish/ha), but stocking at high rates resulted in decreases to the natural portion of the adult population. Available prey metrics and simulations can provide information on the potential for stocking success, which could be used to improve the efficacy of stocking programs.