Identify, Report Sightings, Stop the Spread

Learn how to identify, stop the spread and report sightings for New Zealand Mudsnails and Rusty Crayfish in Colorado. Colorado Department of Natural Resources has created guides to help.
The New Zealand mudsnail competes with native invertebrate species and can destroy forage important to trout and other native fishes. State wildlife officials first discovered this invasive non-native species in South Boulder Creek in 2004. Learn how to identify the New Zealand mudsnails, how to stop the spread and how to report sightings.
The rusty crayfish which were found for the first time in Colorado in 2009 in the Yampa River drainage between Steamboat Springs and the town of Yampa. Because of their larger size and more aggressive nature, rusty crayfish can impact fish populations by consuming small fish and fish eggs, and negatively impact fish and spread unwanted aquatic plants by aggressively harvesting underwater plant beds. Learn more how to identify the rusty crayfish, how to stop the spread and how to report sightings.