Rusty Crayfish (Orconectes rusticus)
Rusty Crayfish: An aquatic alien
Rusty crayfish are one of over 350 species of crayfish in North America. They are one of four crayfish common to the Great Lakes region. Other species are Cambarus diogenes, Procambarus acutus acutus, and in the southerly area of the region, the Procambarus clarki.
Rusty crayfish resemble lobsters, a distant saltwater relative. Sporting a thick, bony plated exoskeleton with oversized claws, a mature crayfish often has rusty spots on either side of the carapace.
They require permanent bodies of water with cover of rocks, logs, or tree branches. Rusty crayfish are voracious feeders and feast on aquatic plants, invertebrates, aquatic insects, and other crustaceans. Detritus, fish eggs, and small fish complete their diet.
A native of the Ohio River Basin, it is considered a threat to Michigan's native crayfish population, and could have environmental and economic impacts on local areas. The major threat is the reduction of aquatic plant beds and the species that live in these communities. Many fish may lose nesting areas and shelter when aquatic plant beds are reduced.
The release of rusty crayfish into Michigan waters by anglers using them as bait has allowed the spread of this non-native species. Michigan's fishing regulations place several restrictions on the use and sale of rusty crayfish in Michigan.