First Asian Carp Found in Lower Wisconsin River

On Wednesday, Wisconsin Department of Natural Resources’ researchers collected a grass carp (this is not the high flying carp that knocks people out of their boat) while shocking the Lower Wisconsin River. The fish was found about 3/4 of a mile below the Prairie du Sac Dam.. It was 40 inches long and weighed 40 lbs. This is the first report of this non-native invasive species in the Wisconsin River. However, the grass carp is not new to the area. The good thing is that there is no evidence of successful spawning by the species in Wisconsin waters. We can hope that these two adults were just on vacation and are not proof of a breeding population. (Note: photo above is not of the carp recently collected in the Lower WI River).

History of Grass Carp in Wisconsin
Grass carp were imported from eastern Asia in 1963 to control submersed aquatic vegetation in aquaculture ponds and were first documented in the Mississippi River along Illinois in 1971. In 1983 it was first found in Northeast Wisconsin (the green square dot on the map) in a stocked pond. It is used as a biocontrol agent to keep aquatic vegetation in check. In 1990 it was found to be stocked in many more ponds at golf courses in Southeast Wisconsin (note all the blue dots). It is illegal to stock grass carp in Wisconsin and these populations have been eradicated.

Impacts
No these suckers don’t spread fins and fly like their cousins the silver carp. However, they do cause damage. Like the common carp, they can alter water quality causing an increase in turbidity, reduced dissolved oxygen, and an increase in plant nutrients. They also remove aquatic vegetation which leads to an alteration in the invertebrate and fish communities.

Join the River Alliance as we partner with Friends of the Lower Wisconsin Riverway, Sauk River PAL and many more to prevent the spread of invasives within the basin! »