Twelve invasive species
- What is it? A crayfish up to 4 inches long with dark spots on its sides
- Where's it from? Native to lakes, ponds, and streams of Ohio, Kentucky, Tennessee, Indiana, and Illinois
- How did it get here? Used by anglers for bait and sold in the pet and biological supply industries, rusty crayfish were probably spread outside their native range by one or all of these pathways.
- Where is it now? In the eastern U.S., it has been found in Maine, Massachusetts, New York, New Jersey, Pennsylvania, and West Virginia where it has become an aggressive and destructive invader.
- What's the harm? Rusty crayfish outcompete native crayfish for food and territory and reduce aquatic plant abundance and species diversity, which impacts the habitat for other crayfish and fish species. They are associated with population declines of game fish such as bluegill, bass, and northern pike.
- How can I learn more? Visit nas.er.usgs.gov/queries/FactSheet.asp?speciesID=214.