Modeling Management Scenarios and the Effects of an Introduced Apex Predator on a Coastal Riverine Fish Community

Abstract.—The flathead catfish Pylodictis olivaris, a carnivorous fish species native to most of the central interior basin of North America, has been introduced into at least 13 U.S. states and 1 Canadian province. Concurrent declines in abundance of native fishes have been reported in aquatic systems where flathead catfish have been introduced. To evaluate the potential impact of this invasive species on the native fish community we developed an ecosystem simulation model (including flathead catfish) based on empirical data collected from a North Carolina coastal river. The model results suggest that flathead catfish suppress native fish community biomass by 5–50 % through both predatory and competitive interactions. However, our model suggests these reductions could be mitigated through sustained exploitation of flathead catfish by recreational or commercial fishers at rates equivalent to those for native flathead catfish populations (annual exploitation 6–25%). These findings demonstrate the potential for using directed harvest of an invasive species to assist in restoring native communities. The introduction and establishment of nonnative species is a widespread and poorly understood global phenomenon. While most species introductions fail or persist unnoticed (Williamson 1996), some lead t