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Invasive Species: Red Swamp Crayfish
Red Swamp Crayfish
Detected in Michigan
Report this species to:
Lucas Nathan, DNR Fisheries Division, firstname.lastname@example.org 517-599-9323
If possible, please take one or more photos of the invasive species you are reporting. Also make note of the location, date and time of the observation. This will aid in verification of your report. You may be asked to provide your name and contact information if follow-up is needed.
- Or - use the Midwest Invasive Species Information Network (MISIN) online reporting tool
- Or - download the MISIN smartphone app and report from your phone - http://www.misin.msu.edu/tools/apps/#home
- Dark red color with bright red raised spots, look like small lobsters.
- Elongated claws and bony exoskeleton.
- Elongated head with a triangular rostrum.
- 2.2 inches - 4.7 inches in length.
Photo courtesy of Chris Taylor, Illinois History Survey, Bugwood.org
Photo courtesy of Saxifraga - Rudmer Zwerver.
Habitat: Red swamp crayfish live in a variety of permanent freshwater habitats. Crayfish are crustaceans that burrow deep into the substrate of their habitat and create large mounds of sand and soil called chimneys with a relatively large hole in the center.
Diet: Crayfish feed heavily on snails, fish, amphibians, and plants.
Native Range: Mississippi river drainage and Gulf Coast.
U.S. Distribution (outside of native range): Established populations in California, Delaware, Illinois, Maryland, Michigan, Ohio, Oregon, South Carolina, Utah, Virginia, Washington, and Wisconsin. Introduced but not established in Alaska, Hawaii, Idaho, Indiana, Nevada and New York.
Local Concern: Red swamp crayfish compete aggressively with native crayfish species for food and habitat. Feeding behavior reduces the amount of available habitat for amphibians, invertebrates, and juvenile fish. Burrowing and foraging behavior can also lead to summer cyanobacteria blooms and eutrophic conditions.
Other Names: Louisiana crayfish/crawfish.
Potential Means of Introduction: Aquaculture/aquarium trade, classroom/laboratory release, live bait dumping, small chance of introduction through fish stocking events.
Native look-alikes and how you can tell them apart from red swamp crayfish:
- Devil crawfish: mostly tan body with red highlights around head, body, and claws
- White river crayfish: color may vary from tan to rusty red color, no bright red bumps