A single grass carp, a prohibited fish species, was caught on Aug. 4 by a bow angler in Racine County’s Wind Lake. The angler, suspecting the fish was a grass carp, sent photos to the DNR to confirm the catch.
“Grass carp have the potential to have large negative impacts on our waters and the fish in them. We want to be sure to limit their spread in Wisconsin,” said Justine Hasz, DNR fisheries bureau director. “Thanks to the action of a knowledgeable angler, the DNR was able to quickly confirm this finding and act on it.”
Grass carp are illegal to possess, transport, and sell in Wisconsin. The species has been moving toward Wisconsin waters from the Illinois River and the Mississippi River. They are also intentionally and illegally stocked in private ponds for aquatic plant control. Grass carp have elongated, torpedo-shaped bodies. Body color is dark olive, shading to brownish-yellow on the sides, with a white belly and large, slightly outlined scales.
Grass carp can grow to be 80 pounds and eat large amounts of aquatic plants which can disrupt the food webs of Wisconsin’s lakes and rivers.
Upon confirmation of the catch, the fish was transferred to the DNR and the Fish and Wildlife Service for genetic testing. Results show that the fish is a sterile triploid fish, indicating that it was likely an intentionally released fish or a purchased fish that escaped from a pond.
“We will work with our aquatic invasive species program to assist Wind Lake with addressing this finding by doing more sampling and reaching out to educate anglers,” said Laura Stremick-Thompson, the area DNR inland fisheries supervisor. “Fortunately, the fish was a sterile triploid fish and the impacts are limited this time, but that only underscores our need to be cautious.”
To prevent the release of grass carp, Wisconsin residents and water users are reminded to:
- Check the prohibited species list before purchasing fish or releasing them into private ponds.
- Avoid releasing live bait, which could be contaminated, into Wisconsin waters.
- Contact DNR lakes and rivers staff with questions about how to responsibly manage aquatic plants.