Select a subject area below for specific news and information regarding Asian carp and control efforts.
Asian carp are headed toward Wisconsin waters and pose a threat to boater safety, fishing, and ecosystem health.
© Chris Olds, USFWS
Asian carp species Asian carp species introduced into the United States are headed toward Wisconsin waters. Asian carp environmental DNA has been found above the electric dispersal barriers in Lake Calumet, seven miles from Lake Michigan on the Indiana-Illinois border, and in 2013, in a single water sample collected from Sturgeon Bay, Wis. . Individual adult fish have been found on occasion in Wisconsin waters of the Mississippi River and in the Lower Wisconsin River.
The good news is no young fish have been found nor have any other signs of reproduction been found in any Wisconsin waters to date.
Also, dams on the Wisconsin River at Prairie du Sac and on the St. Croix National Scenic Riverway at St. Croix Falls would block Asian carp on the Lower Wisconsin River or the Mississippi River from travelling farther inland in Wisconsin.
These Asian carp species are a serious concern because they can aggressively compete with native commercial and sport fish for food and can potentially disrupt entire ecosystems. Also, silver carp can injure boaters when the fish leap out of the water.
Wisconsin has been working with states and federal agencies involved in managing the Mississippi River and Great Lakes to address aquatic invasive species, including keeping Asian carp from getting established in the Upper Mississippi River and in the Great Lakes. The two basins are artificially connected through the Chicago waterway system. Wisconsin has joined other states in legal action to sever that connection. Other actions are listed below.
DNA sampling finds no evidence of Asian carp in the Fox and Milwaukee rivers in 2015
Issued by DNR Central Office on Tuesday, August 25, 2015 at 1:21:48 PM
No Asian carp environmental DNA found after additional testing in Lower Fox River
Issued by DNR Central Office on Friday, November 07, 2014 at 10:31:19 AM
Young Asian carp are hard to tell from young gizzard shad and many minnow species. Adult Asian carp have features that can help anglers identify these invaders from older native fish and from common carp. Common carp, invasive nonnative fish that have been in Wisconsin for more than a century, continue to cause problems but the four Asian species are expected to potentially cause even greater harm to fish, mussels, lakes and rivers.
Characteristics include: Characteristics include: Characteristics include: Sources: Asian Carp Regional Coordinating Committee, Wisconsin Fish Identification Database
Bighead carp body
Bighead carp head
Black carp and grass carp
Grass carp body
Grass carp head
Silver carp body
Silver carp head
Sources: Asian Carp Regional Coordinating Committee, Wisconsin Fish Identification Database
Frequently asked questions about asian carp.
There are four species of Asian carp that are considered invasive and a threat to Wisconsin waters: the bighead, silver, grass and black carp. Silver and bighead carp are filter-feeding fish and consume plant and animal plankton at an alarming rate. Bighead carp can grow to very large sizes of over five feet in length and can weigh 100 pounds or more. Black carp differ in that they consume primarily mollusks, and threaten native mussel and sturgeon populations. They can grow to seven feet in length and 150 pounds.
Asian carp were originally imported to the southern United States in the 1970s to help aquaculture and wastewater treatment facilities keep retention ponds clean. Flooding throughout the 1990s allowed these fish to escape into the Mississippi and migrate into the Missouri and Illinois rivers.
Asian carp are a problem because of their feeding and spawning habits. Bighead carp are capable of consuming 20 percent of their own body weight in food each day. Silver carp are smaller, but pose a greater danger to recreational users because of their tendency to jump out of the water when disturbed by boat motors. They can severely impact fishing and recreation. They can spawn multiple times during each season and quickly out-compete native species by disrupting the food chain everywhere they go.
Asian carp could have a devastating effect on the Great Lakes ecosystem and a significant economic impact on the $7 billion fishery. Once in Lake Michigan, this invasive species could access many new tributaries connected to the Great Lakes. These fish aggressively compete with native commercial and sport fish for food. They are well suited to the water temperature, food supply, and lack of predators of the Great Lakes and could quickly become the dominant species. Once in the lake, it would be very difficult to control them.
During 2002 monitoring efforts, Asian carp were detected in the upper Illinois River, just 60 miles from Lake Michigan. In 2009, by using a new method called eDNA testing, silver carp were detected considerably closer, within the Lockport Pool (Des Plaines River, and I & M Canal).
The Chicago Sanitary and Ship Canal (CSSC) is a manmade waterway that provides a direct connection between the Mississippi River system and Lake Michigan. eDNA sampling suggests that the carp are already about a mile from the electric barrier located within the CSSC that is designed to deter them from advancing through the canal to Lake Michigan.
Other points of possible entry to the CSSC above the electric barrier are the low lying areas of land positioned between the Des Plaines River, the Illinois and Michigan (I & M) Canal and the Chicago Sanitary and Ship Canal. During heavy rainfall events, these areas are prone to flooding. A significant rain could flood the banks, joining the Des Plaines with the CSSC or the I & M canal with the CSSC, and allowing these fish to bypass the barrier and advance toward Lake Michigan. The U.S. Army Corps of Engineers and others are currently investigating potential solutions to these bypass issues.
FAQ provided by Illinois Department of Natural Resources
Efforts to keep carp out of the Great Lakes
Efforts to keep carp out of Wisconsin's Mississippi River waters
For questions about the electric barriers/maintenance, eDNA evidence
For questions about the Chicago Sanitary and Ship Canal closure
For questions about the impact of Asian carp on the Great Lakes
For questions about the impact of Asian carp on the Great Lakes