Rusty Crayfish

Rusty Crayfish (RC)

Where are RC from and how did they get here?
RC are native to the Ohio River Basin. They are likely spread through non-resident anglers who transport them to use as bait.

How do I identify RC?
You can distinguish a RC from a native crayfish by the rusty red spots on the middle portions of their bodies. Their claws are usually more robust than native crayfish, and have black tips.
Please contact our Water Program Coordinator if you think you have found RC.

Note the RC's rusty side spots and black claw tips

How do RC affect Wisconsin water bodies?
RC are aggressive, and displace native crayfish. They are “clear cutters,” and cut down aquatic vegetation. This decreases habitat for small fish. They also decrease the density and variety of invertebrates.

What can be done once RC enter a water body?
Intensive trapping and harvesting may lower populations of RC in a water body, but it will not completely eliminate the population. The best method of treatment is prevention. Education to anglers, bait dealers, and the general community will help to ensure RC are not spread to additional water bodies.

Additional Resources

Manitowish Waters Lakes Association

Wisconsin DNR Aquatic Invasive Species

Citizen Lake Monitoring Network: Get Involved!

Great Lakes Indian Fish & Wildlife Commission (GLIFWC) Invasive Species Area Maps

US Geological Survey Invasive Species Research

Vilas County Land and Water Conservation Department

Invasive Plants Association of Wisconsin



Available for loan.

Lake Plants You Should Know- A Visual Field Guide. University of Wisconsin- Extension.

Aquatic Plants of the Upper Midwest- A Photographic Field Guide To Our Underwater Forests.Written by: Paul Skawinski.

Through the Looking Glass- A Field Guide to Aquatic Plants. Written by: Susan Borman, Robert Korth, and Jo Temte.

Saving Our Lakes and Streams. Written by: James A. Brakken.

Your Help Is Needed

Curly leaf pondweed has been found in the Manitowish Waters Chain. Please keep your eyes open and let us know if you see this aquatic invasive plant along your shorelines or docks. Additionally, please check your boats and props to prevent the spread!

Citizen AIS Lake Monitoring

Join a crew to search for suspicious-looking species (plant or animal). Keep your eyes peeled and report any sightings to us.

Clean Boats Clean Waters

Educate boaters at landings and inspect boats and trailers.

Volunteer today, to protect our waters tomorrow.

Phone: (715) 543-2085

AIS of the Month

September: Mystery Snails

August: Eurasian Water Milfoil

July: Purple Loosestrife

June: Curly Leaf Pondweed