Unintended Consequences of Invasive Species Management: Asian Carp Barriers May Also Constrain Long-Term Dynamics of the Native Fish Assemblage

Preventing the spread of aquatic invasive species is often much more cost- and ecologically effective than trying to control them post-invasion. However, popular control methods such as the use of barriers can have their own ecological impacts. For instance, barriers proposed at Brandon Road Lock and Dam (BRLD) meant to keep silver and bighead carps from entering the Great Lakes would also prevent upriver movement by native fishes. Indeed, surveys and assessments suggest upriver lockage has allowed native fish to re-establish in recently improved reaches of the Illinois and Des Plaines Rivers. Our research aims to characterize the consequences of barriers that are anticipated to eliminate the only migratory corridor for native fishes at BRLD. By integrating available information into a conceptual model, we identify potential consequences of hydrologic separation affecting primarily native fishes and freshwater mussels. We hypothesize that the loss of supplementary immigration of native fishes through BRLD will slow the rehabilitation of the Des Plaines River fish community and potentially limit freshwater mussel rehabilitation. We anticipate that our conceptual model will eventually guide both future research priorities and mitigation efforts aimed at minimizing any negative outcomes of a hydrologic separation on aquatic resources upriver of BRLD.