Invasive Fishes in the Large Rivers of the United States

The number of different non-native fish species that have reached problematic population densities in the large rivers of the United States is not high, but a few species have become problematic or generated strong concerns.  Such species from outside the United States include Bighead, Silver, Grass, and Black Carps (together known as the “Asian carps”) and Common Carp, Goldfish, and Northern Snakehead.  Other species such as Flathead and Blue Catfishes and White Perch have been moved outside their native range within the United States and are considered problematic in their introduced range.   The stochastic conditions of large rivers create special problems for understanding the effects of these fishes.  Likewise, the connectivity and flows of large rivers provide pathways for range expansion and create problems for control.  A broad overview of the sources of these fishes, research into their effects, and current control efforts is provided, focusing on fishes deemed undesirable.