Rusty Crayfish

Faxonius rusticus

The rusty crayfish (Faxonius rusticus, formerly Orconectes rusticus) is a large freshwater crayfish native to the Ohio River basin in North America. Adults reach 10-13 cm in body length and display a brown to greenish-brown body with distinctive rusty-red patches on each side of the carapace, which give the species its common name. The claws are greyish-green with dark black bands at the tips. They inhabit lakes, rivers, and streams with rocky or gravelly bottoms at depths of 0-10 meters, preferring areas with cover such as rocks, logs, and aquatic vegetation. They are aggressive omnivores feeding on aquatic plants, invertebrates, fish eggs, and detritus. As an invasive species outside their native range, they can significantly alter aquatic ecosystems by reducing aquatic vegetation and displacing native crayfish. Divers encounter them in clear freshwater sites throughout eastern North America, where their bold behavior and distinctive markings make them easy to identify and observe.