Predicting Long-Term Genetic Integration Following Stocking of Florida Bass (Micropterus salmoides) into an Arkansas Reservoir

Abstract

Management agencies within native largemouth bass (LMB; Micropterus nigricans) range across the United States regularly stock non-native pure Florida bass (FLB; Micropterus salmoides) or reciprocal LMB × FLB F1 hybrids to enhance angling opportunities based on public demand. Often, these stocked fish are introduced into waterbodies already occupied by LMB, which readily hybridize with FLB. This hybridization and resulting genetic integration of FLB alleles into the population is often considered the goal of stocking programs. However, managers have little available information to help them determine stocking rates and durations that will allow them to meet management goals associated with the introgression of FLB alleles. To inform such stocking decisions, we created an individual-based model and parameterized it based on the results of a recent FLB stocking program in Lake Ouachita, Arkansas. The model closely predicted lakewide genetic integration empirically observed in Lake Ouachita following stocking. We then used the model to predict long-term genetic integration outcomes and assess how varying stocking rates would affect timing of achieving stocking goals. Model results indicate that when management agencies are stocking at low rates, such as the rate utilized in Lake Ouachita (6.2 fish ha–1), they should consider committing to a long time frame (e.g., multi-decade) to integrate FLB alleles at a high level. Alternatively, greater stocking rates can yield much faster results but may be resource prohibitive. This model provides information on how agencies could allocate limited resources to best achieve FLB stocking goals in states such as Arkansas where FLB are non-native and are stocked to change the genetic composition of an existing LMB population.