Rusty crayfish are an aquatic invasive species. If you find a rusty crayfish in your crayfish traps or while fishing, the Wyoming Game and Fish Department advises that you take a photograph of it and kill it. The easiest way to kill a crayfish is to break them in half by separating the tail from the carapace — the section of the body behind the head. Send an email to reportais@wyo.gov with the photo and the most accurate location you can provide where the rusty crayfish was found.  

Rusty crayfish are generally 3-5 inches long. They are grayish-green and have a reddish spot on each side of the body just in front of the tail. The rusty-red spots look like fingerprints, as if someone picked up the crayfish and squeezed it.

Rusty crayfish are native to the Ohio River Basin but have spread to other states. They were first discovered in Wyoming in 2006 after being illegally introduced into private ponds in the North Platte watershed near Douglas. In 2020, they were discovered in the Laramie River near the Laramie Peak WHMA from another illegal introduction. 

The species can cause a variety of negative environmental and economic impacts when introduced to new waters. Game and Fish needs your help to prevent the spread of this species. Do not move rusty crayfish to new waters. Introductions will have lasting ecological consequences including displacing native crayfish species, reducing the amount and kinds of aquatic plants and invertebrates and even preying on some fish populations. It is illegal to possess or move rusty crayfish or other listed aquatic invasive species.