PRAIRIE DU SAC - With state fisheries crews recently catching four bighead carp on the Lower Wisconsin River and finding another dead along the shore, anglers who catch one of the invasive carp species are reminded to keep the fish and contact their local fish biologist.
"Anyone who catches a fish they believe to be an Asian carp species - bighead, silver, black or grass -- should keep the fish, make sure it's dead before they leave the riverway, and contact their local fisheries biologist to verify the species," says David Rowe, a fisheries supervisor based in Fitchburg.
"They can be very prolific and outcompete native species and we want to keep them out of the Lower Wisconsin Riverway."
It is illegal to transport a live Asian carp, so anglers will want to make sure the fish is dead before taking it away, Rowe says. He reminded anglers to avoid moving bait fish to prevent the spread of aquatic invasive species or fish diseases.
The carp have been occasionally captured in Wisconsin waters of the Mississippi River and Lower Wisconsin River since 1996. They have not been found in inland waters above the lower dams on the Mississippi tributaries. DNR fisheries crews captured four adult bighead carp this fall while doing routine surveys to monitor the lake sturgeon population below the Prairie du Sac Dam. They also recovered another bighead carp that was freshly dead on the shore, according to Nate Nye, the DNR fisheries biologist for Columbia and Sauk counties.
DNR believes the Asian carp are individual fish that strayed and do not represent an established population. No other such carp were found by DNR on the river over the summer despite multiple other fish surveys that likely would have turned up if they were there. Nor did DNR hear any reports from anglers that they caught Asian carp.
"These fish were the only ones we saw," Nye says. "They were all very large adults that likely migrated up into the lower Wisconsin River from the Mississippi River this spring or summer when we had high river flows, which can be an environmental trigger for their carp species."
Bighead and silver carp are filter feeders and directly compete with native species like paddlefish and buffalo, but also because they are large bodied fish that eat very low on the food chain they can harm the entire fish community, Nye says.
More information about Asian carp, including a map of the carp found in Wisconsin waters and photos to help identify their species, is available on DNR's web site, dnr.wi.gov by searching "Asian carp control."
Anglers and boaters can avoid spreading invasive fish and other aquatic invasive species by taking steps including inspecting boats and trailers after leaving a waterbody; removing all attached aquatic plants and animals; draining all water from boats and equipment; and never moving plants or live fish away from a waterbody.