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 exposed east of the Continental Divide in Colorado state executives noted in a news release Wildlife personnel commented the crayfish was shared on April in Larimer County s West Fork Little Thompson River by a user on iNaturalist a species identification app A group 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 guidance state wildlife authorities revealed The crayfish has been proven 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 executives declared 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 stated Robert Walters CPW s Invasive Species Activity 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 revision law changed permitting It s peak bird migration season in Colorado But their populations are in a steady decline Environment change is making coffee more expensive Tariffs likely will too EPA must reconsider Colorado s decision to ignore fracking toxicity in state plan to clean the air Colorado and Denver narrated 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