Species and Origin: Rusty crayfish are crustaceans that grow up to 5 inches long. They are native to the Ohio River basin. Their carapace usually has a pair of rusty-colored spots and claws often have black bands at their tips.
Impacts: Rusty crayfish are aggressive invaders. They can harm native fish communities by feeding on their eggs and young, drive out or hybridize with native crayfish, and eliminate aquatic vegetation.
Status: Rusty crayfish have spread to several states and Ontario. They were discovered in Minnesota around 1960 and are confirmed in about 50 Minnesota waters, mostly in central and northern counties.
Where to look: They can infest lakes, rivers, streams and wetlands.
Means of spread: They likely spread through dumping of bait buckets and aquariums, and activities of commercial aquaculture.
Regulatory classification (agency): Rusty crayfish is a regulated invasive species (DNR), which means release into the wild is illegal. Licensed anglers may collect any crayfish for use as bait on the same waterbody. They can also harvest up to 25 pounds of any crayfish for personal consumption. Selling live crayfish for bait or aquarium use is illegal.
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More on rusty crayfish from Minnesota Sea Grant