The marbled crayfish, a self-cloning invasive species, was added to Michigan’s Prohibited Species list this month by order of Dan Eichinger, director of the state’s department of natural resources.
Both its self-cloning and invasive nature are among the reasons the crayfish “cannot be possessed, introduced, imported, sold or offered for sale as a live organism, except under certain circumstances,” according to a statement from the department.
Marbled crayfish are considered a “least-wanted” aquatic species by the Conference of Great Lakes and St Lawrence Governors and Premiers’ list, the statement said, and the order puts Michigan in alignment with the group.
The crayfish are considered to “pose a serious threat to the environment and economy,” the statement says.
“All known specimens are genetically identical females that can produce up to 700 eggs per reproductive cycle without the need for fertilization,” the statement said.
“If a single marbled crayfish escaped captivity or was released into open water,” the statement read, “it could have the potential of initiating an entire population because it can individually reproduce in large numbers.”
The species is not native to Michigan, but is popular in the “aquarium trade.” The statement claims the species, if introduced to rivers or lakes or streams in Michigan, would quickly “dominate” its new home.
People who already own marbled crayfish cannot sell or trade them in Michigan, according to the order. The state asks that owners “humanely dispose of any specimens in their possession,” cleaning their tanks so that new eggs do not survive.
But don’t flush them, the state says, as flushing is neither humane nor effective in stopping their spread.
“(F)lushing an aquatic animal down a drain or toilet is not considered humane and does not necessarily kill the animal, but can introduce it into a water system,” the statement said.
Nor should the crayfish be released into waters, as knowingly releasing a prohibited species into the wild is a felony.
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