Chapter 11: Population and Distribution Control Measures for Bigheaded Carps in North America
Control programs that successfully reduce abundance or control the distribution of nonindigenous fishes typically integrate a variety of strategies targeting the species of concern (Dawson and Kolar 2003). Distribution control strategies must consider both range expansions by the fish through natural or artificial waterways and anthropogenic transfers over natural or artificial barriers (i.e., between basins or over dams). Preventing further introductions, controlling additional spread, and reducing abundance of established populations of bigheaded carps will require development and implementation of new technologies, will probably require many years, and will be economically and perhaps environmentally costly.
In an analysis of potential measures to control the expansion of bighead and silver carps into Minnesota, FishPro Consulting Engineers and Scientists (2004) suggested that the following topics should be included: (1) public education; (2) research and monitoring, especially in new control techniques; (3) regulation of bighead and silver carps and enforcement of rules and regulations pertaining to the species; (4) fisheries management; (5) barriers and deterrents to prevent bighead and silver carps from spreading into areas not yet infested; (6) ecological risk assessments to predict present and future distribution; and (7) targeted harvest, not managed to be sustainable, are the best measures to control future spread of these fishes. A management and control plan for Asian carps in the United States is currently in review (Conover et al. in review).
Bigheaded carps have used the Mississippi River and its tributaries, which drain 40% of the 48 contiguous states of the United States (Wiener et al. 1998), as conduits for range expansion to most of the midsection of the country. Bigheaded carps are robust swimmers that can travel many kilometers in a season. The dam on the Missouri River at Gavins Point, South Dakota, has prevented upstream movement beyond that point, but major dams on the Mississippi River and other major tributaries have locks providing for navigation and many have other design attributes that allow fish passage up or downstream during high water. Bigheaded carps are now abundant in the Mississippi River as far upstream as pool 16, between Illinois and southern Iowa (with a few fish captured as far upstream as Lake Pepin, Minnesota). They have successfully navigated several lock and dams on the Ohio, Tennessee, and Illinois rivers.