Rusty crayfish have invaded portions of Minnesota, Wisconsin, Ontario and other areas. They were probably spread by non-resident anglers who brought them north to use as fishing bait. The invading crayfish frequently displace native crayfish, reduce the amount and kinds of aquatic plants and invertebrates, and reduce some fish populations. The best way to prevent further problems is to prevent or slow their spread into new waters through public education.
This publication was revised in 1999.