Invasive Red Swamp Crayfish Discovered at Michigan Hatchery

The Michigan Department of Natural Resources (DNR) has confirmed the presence of invasive red swamp crayfish in a rearing pond at Wolf Lake State Fish Hatchery near Kalamazoo. This species, prohibited in Michigan since 2014, was found after the pond was drained following a muskellunge fish stocking operation.

Red swamp crayfish were first discovered in Michigan in 2017, and since then, isolated populations have appeared in six counties. The DNR believes they likely entered the hatchery via contaminated water, bait, aquarium releases, or possibly through forage fish sourced from other states.

These crayfish pose serious ecological threats:

• They outcompete native crayfish for food and habitat.
• They reproduce rapidly.
• Their burrowing damages shorelines and infrastructure.

Fortunately, officials say it’s unlikely the crayfish were released into lakes during recent stocking efforts, as fish were handled individually. However, the DNR has launched a containment response, setting 165 traps and planning to use environmental DNA (eDNA) to investigate the source and extent of the infestation.

The DNR is encouraging the public to help by reporting sightings. Photos or frozen specimens can be sent to the Fisheries Division, and more information is available at Michigan.gov/Invasives.

Read the full story on the Lansing State Journal.