Exploring the importance of metapopulation dynamics with population control strategies for invasive silver carp in the upper Mississippi River

Invasive bigheaded carps (Bighead Carp Hypophthalmichthys nobilis, Silver Carp Hypophthalmichthys molitrix, and their hybrids Hypophthalmichthys spp.) currently infest the Mississippi River Basin. Bigheaded carps can outcompete native species in invaded waters and can also transform the surrounding environment. Currently, resource managers seek to limit the population abundance of bigheaded carps and their range expansion into additional regions of the Upper Mississippi River (UMR) but lack a tool to evaluate different control strategies. Here, we present an application of a Silver Carp spatial population model in the UMR to fill this gap. We used the model to explore how simulated control strategies could affect Silver Carp metapopulation dynamics. More specifically, we assessed and compared the importance of movement deterrents, removal locations, and recruitment areas on Silver Carp population abundances across the UMR. Strategies that included a combination of removal efforts and deterrents resulted in the largest decreases in Silver Carp abundance in the upper pools of the UMR. Furthermore, scenarios that targeted source populations of Silver Carp rather than sink populations resulted in larger decreases in Silver Carp abundance at the invasion front. The effectiveness of these combined simulated strategies also depended on the location of Silver Carp recruitment. Our work suggests that an understanding of Silver Carp metapopulation dynamics may be important for control efforts and could help to inform the management of Silver Carp in the UMR.