Environmental DNA from invasive silver carp found in the Michigan River

Routine environmental DNA (eDNA) testing for invasive carp found one positive sample in the Michigan River.

The U.S. Fish and Wildlife Service conducts annual tests for bighead and silver carp. This year, they found one positive sample in the St. Joseph River near the St. Joseph/Benton Harbor area.

Only one of 220 water samples collected in June 2023 from stretches of the river between Lake Michigan and Berrien Springs showed evidence of silver carp genetic material. That sample was taken near Marina Island.

“A positive eDNA sample does not necessarily indicate the presence of live fish,” said Seth Herbst, DNR fisheries research program manager. “Genetic material could be introduced from other sources, such as boats or fishing gear used in another state where invasive carp are present, and then transported and used in Michigan waters.”

The sample was taken directly in front of the marina. Officials said this may mean that boat movement may have contributed to the discovery.

“We use the eDNA results as one piece of information to determine the best response to the potential threat of invasive species,” Herbst said. “In this case, we have requested assistance from the U.S. Fish and Wildlife Service to conduct another round of eDNA sampling in the St. Joseph River beginning September 5, with the results processed as soon as possible.”

The USFWS has been conducting monthly electrofishing and trawling operations in the St. Joseph River every summer since 2022 to capture and remove grass carp. They did not catch or spot any silver carp.

There is no evidence of any live silver or black carp in the Great Lakes or in Michigan rivers, officials said. Anglers are encouraged to learn how to identify bighead and silver carp and their species Report any suspicious fish.

“Along with our participation in the eDNA monitoring program, we continue early detection efforts, such as conducting fish population surveys, raising awareness among anglers, and maintaining an invasive carp reporting website for anglers to share any suspicious catches or observations that occur during their outings,” Herbst said. “.

—> Learn about 17 invasive fish Michiganders should know about