Federal report confirms naturally reproducing grass carp found in Lake Erie
In the past three years the Department of Natural Resources (DNR) has received increased reports of grass carp being captured in Lake Erie by commercial fishermen. These fishermen have also reported seeing more of this species, as well as specimens of varying age and size indicating there may be a naturally reproducing population in the lake. This assumption has been confirmed by a recently released U.S. Geological Survey (USGS) report.
USGS has determined grass carp, a species of Asian carp, are naturally reproducing within the Lake Erie basin. Grass carp do not present the same ecological risk to Michigan’s waters as bighead carp or silver carp, although they are a species of concern because they feed on aquatic plants and can significantly alter habitat required by native fish. Grass carp have occasionally been found in Michigan waters since the late 1970s.
Grass carp captured in Michigan’s waters of the Great Lakes were thought to be the result of fish movements from other states where stocking genetically altered (triploid) fish for aquatic vegetation control is allowed. Triploid fish are sterilized through a heat-treating process when their eggs are developing. Several Great Lakes states allow the stocking of triploid fish because they believe the fish have a low probability of reproduction, although the sterilization process may not be 100-percent effective.