Rusty crayfish, an ‘aquatic nuisance,’ discovered in northern Colorado river

Rusty crayfish an aquatic nuisance and an invasive species has been discovered in a Larimer County river south of Estes Park according to Colorado Parks and Wildlife This is the first time the crayfish has been approved in the agency s northeast region and the second time it s been unveiled east of the Continental Divide in Colorado state agents stated in a news release Wildlife executives mentioned the crayfish was revealed on April in Larimer County s West Fork Little Thompson River by a user on iNaturalist a species identification app A squad from Colorado Parks and Wildlife was able to confirm the aquatic nuisance s presence with genetic testing later that month according to the agency s news release The rusty crayfish is native to the Ohio River basin and is one of Colorado wildlife managers top invasive concerns in the state It is larger and more aggressive than Colorado s native crayfish species often outcompeting them for food and support state wildlife personnel explained The crayfish has been approved in five Colorado waterways since including Lake Granby in August according to the release Wildlife managers believe they were introduced after anglers used them as bait State officers noted the rusty crayfish is classified as a prohibited aquatic nuisance species due to their voracious appetite on critical habitat vegetation and prolific reproduction habits Rusty crayfish are much more aggressive than our native crayfish species and are not an ideal food source for our sportfish mentioned Robert Walters CPW s Invasive Species Effort Manager in the release They also eat aquatic vegetation which native fish rely on for spawning cover and food Related Articles Fights persist over oil and gas drilling near Front Range homes six years after reorganization law changed permitting It s peak bird migration season in Colorado But their populations are in a steady decline Context change is making coffee more expensive Tariffs likely will too EPA must reconsider Colorado s decision to ignore fracking corruption in state plan to clean the air Colorado and Denver described owners to cut their buildings carbon emissions Did the rules go too far The rusty crayfish has dark black rings near the tips of its claws and eponymous rusty patches on either side of its abdomen Males can grow up to five inches long Colorado wildlife crews are working to conduct additional surveys of the Little Thompson River to determine the size and extent of the invasive population Get more Colorado news by signing up for our daily Your Morning Dozen email newsletter