DNR to remove grass carp from Marrs Lake, Lenawee County
As a result of previous grass carp reports in Marrs Lake (located in Lenawee County), staff from the Michigan Department of Natural Resources’ Fisheries Division sampled the water body during the week of June 18. One adult grass carp was collected along with the sighting of at least three others. Tissue samples from the grass carp were submitted to laboratories at U.S. Fish and Wildlife Service and Southern Illinois University to determine their reproductive status. Both institutions confirmed the collected fish was a reproductively viable grass carp.
In response to this finding, Fisheries Division is developing a Grass Carp Management Plan for Marrs Lake that will include an intensive sampling effort with electrofishing and nets in an attempt to remove the remaining grass carp without harming other fish. This effort is planned for the week of July 16. Additionally, the connected lakes (Washington, Wolf and Allen) will be sampled for grass carp DNA to see if these fish have spread to these other water bodies and to determine if additional management steps are needed for these locations.
Grass carp are considered an Asian carp species, and while they do not pose the same risk to Michigan’s waters as bighead or silver carp, they are of concern as they eat beneficial types of aquatic plants and alter good fish habitat. Grass carp are rarely found in Michigan waters. Previous cases were usually a result of illegal stocking in ponds or movements from other states where stocking genetically altered triploid fish for aquatic vegetation control is allowed.
Other states allow the stocking of triploid fish because they believe the fish have a low probability of reproduction, but the sterilization process is not 100 percent effective. Given their potential negative effects on fish habitat, the Michigan Department of Natural Resources strongly opposes the use of triploid fish and reminds the public that grass carp are illegal to possess and stock in both public and private waters.
The DNR’s Fisheries Division has been communicating with the waterfront residents of Marrs Lake for assistance on this matter and will continue to closely coordinate with them.
