Michigan is testing new approaches to combat invasive crayfish

By Elinor Epperson

Image: A Michigan Department of Natural Resources technician collects a red swamp crayfish from a retention pond in Novi in ​​August 2022. Matthew Clara/ DNR

Researchers are studying new techniques to remove an invasive crayfish from Michigan waters.

The Michigan Department of Natural Resources has been battling an invasion of red swamp crayfish since they first appeared in the state in 2017. Aggressive attempts to capture and remove the crustaceans have been unsuccessful.

Kathleen Quebedeaux, a DNR fisheries biologist, said different approaches are needed to eradicate the invader.

“To eradicate the disease more effectively, we need other means,” she said. These include treating with pesticides, using predatory fish and lighting traps.

The DNR has partnered with several agencies and organizations to maximize research and funding.

New possible solutions to the crayfish problem come from the U.S. Geological Survey, Michigan State University, Auburn University and the Wisconsin Department of Natural Resources.

A tool that is not new: the attempt to raise public awareness.

“The introduction of these crayfish everywhere is due to humans,” she said. “If people are aware of the problem, we can prevent the introduction in the first place.”

Possession of live red swamp crayfish is illegal in Michigan, but they still find their way north due to their popularity as educational tools, aquarium animals and seafood.

People have also played a key role in curbing the spread of the disease.

Most early detections of the crayfish are done by the public, Quebedeaux said. Identification materials are available through Michigan State University Extension.

There are about 600 species of crayfish worldwide, more than half of which live in North America.

The red swamp crayfish, native to the Gulf Coast, threatens Michigan’s eight native species. The invader displaces native species for food, reproduces rapidly, and preys on less dominant crayfish.

“They eat anything they can get their hands on,” said Quebedeaux. The crustacean’s aggressive digging also disrupts water quality and the stability of the banks.

The invasive population is largely confined to the Detroit metropolitan area, with some exceptions in Howell and West Michigan.

It is not yet widely used.

“That’s one of the reasons we’ve responded so aggressively,” she said. “We believe the invasion is early enough in the process … that we believe eradication is possible.”

Elinor Epperson is completing an environmental reporting internship as part of the MSU Knight Center for Environmental Journalism’s diversity reporting partnership with the Mott News Collaborative. This story was produced for Public of Michigan.