Rusty Crayfish (Orconectes rusticus) Rusty crayfish are an aggressive species with the ability to alter the aquatic food chain in non-native ecosystems. Thought to be native to the Ohio River Basin, the rusty crayfish was likely introduced by anglers who dumped their leftover bait into waterways. Rusty crayfish are now found in Michigan, Massachusetts, Missouri, Iowa, Minnesota, New Mexico, New York, New Jersey, Pennsylvania, Wisconsin, and all New England states except Rhode Island.
The impacts of rusty crayfish are severe and can reverberate through the aquatic food chain. First, rusty crayfish are much more aggressive than native crayfish species. Therefore, they often displace native crayfish species which are an important food source for fish. Rusty crayfish can also reduce aquatic plant abundance and species diversity. In turn, this can impact aquatic invertebrates (which provide food for fish and ducks) that rely on submerged aquatic plants for food and cover. Submerged aquatic plants also provide food and shelter for young gamefish, nesting areas for fish, and erosion control.
Rusty crayfish looks similar to native crayfish species but can be identified by more robust claws, and by dark, rusty spots on each side of their carapace (shell).
The best way to manage rusty crayfish is to prevent furthering their spread. You can help by using bait native to the waterbody you fish in and by never dumping leftover bait or unwanted aquarium pets into waterways.
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The University of Minnesota Extension