Crayfish, also known as 'crawdads', are a popular bait and food item. From crayfish boils to bait for fishing, it is not uncommon to find people collecting these small crustaceans from Colorado waters. Rusty crayfish are an aggressive crayfish native to the Ohio River basin in the upper Midwest but human activity has moved them throughout the northeast and into southern Canada. The discovery of rusty crayfish in the Yampa basin is the first time this species has been found in Colorado. Because of their larger size and more aggressive nature, rusty crayfish can impact fish populations by consuming small fish and fish eggs. They can also negatively impact fish and spread unwanted aquatic plants by aggressively harvesting underwater plant beds.

Identification of rusty crayfish is extremely difficult and generally requires analysis of mature males. Because of the identification challenge, it is unlikely that anglers will be able to identify rusty crayfish from other crayfish that can be found in the Yampa River basin.

To prevent the spread of rusty crayfish within and beyond the Yampa River basin, the Director of the Division of Wildlife has issued an immediate order that prevents the removal of any live crayfish from the Yampa River, and any streams, lakes, canals or rivers that adjoin the Yampa River. Anglers gathering crayfish must either immediately return the live crayfish to the water where it was captured or immediately kill the crayfish by separating the edible tail portion from the body of the crayfish. Once killed by separating the tail from the body, dead crayfish may then be transported for consumption. Under this order transportation of live crayfish is not allowed in the Yampa River basin.

Division of Wildlife aquatic biologists and specialists in aquatic nuisance species are beginning analysis to determine the distribution of rusty crayfish within the Yampa Basin and to determine if they have spread to other waters in the state. Additional regulation to address this issue is under consideration by Division staff and will be presented to the Wildlife Commission through the standard regulatory process.

Anyone with questions or comments about rusty crayfish or this closure can contact Elizabeth Brown, Division of Wildlife Aquatic Nuisance Species Coordinator, at (303) 291-7362.

News Source: Colorado DOW - Apr. 13, 2010