Invasive, self-cloning marbled crayfish now a prohibited species in Michigan


Marbled crayfish are named for the streaked or marbled appearance of the shell and claws. Photo courtesy of Ranja Adriantsoa.

Mich. (WJMN) – Department of Natural Resources (DNR) Director, Dan Eichinger, has approved the addition of marbled crayfish (Procambarus virginalis) to Michigan’s list of prohibited species.

Species that are prohibited in Michigan cannot be possessed, introduced, imported, sold or offered for sale as a live organism, except under certain circumstances.

According to a press release, Marbled crayfish, also known as marmorkrebs and virgin crayfish, are increasing in popularity in the aquarium trade due to their unique ability to reproduce by cloning. All known specimens are genetically identical females that can produce up to 700 eggs per reproductive cycle without the need for fertilization.

Adding marbled crayfish to the state’s list of prohibited invasive species aligns Michigan with the Conference of Great Lakes and St. Lawrence Governors and Premiers’ list of “least wanted” aquatic invasive species, those that pose a serious threat to the environment and economy in the Great Lakes-St. Lawrence River region.

According to NREPA Part 413, a species can be listed as prohibited if it is not native or naturalized in the state and either can cause human or environmental harm or lacks effective management controls. Marbled crayfish have not been detected in the wild in Michigan. However, if a single marbled crayfish escaped captivity or was released into open water, it could have the potential of initiating an entire population because it can individually reproduce in large numbers.

“Marbled crayfish are believed to originate in the aquarium trade, and as such, they have no documented native range,” said Lucas Nathan, DNR aquatic invasive species coordinator. “In some areas where they have been released in Madagascar and several European countries, they have become established and spread rapidly.”

Those who suspect they have found a marbled crayfish in the wild should photograph it, record the location and time, and report the find to Lucas Nathan, DNR aquatic invasive species coordinator, at 517-284-6235 or If it is possible to capture the crayfish, place it in a container in the freezer until it can be analyzed.

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