Adult Zebra Mussel Found in Western Colorado

Zebra mussel shells

Colorado Parks and Wildlife (CPW) has confirmed the presence of an extremely invasive zebra mussel in Highline Lake at Highline Lake State Park in Loma, CO. This is the first time an adult zebra mussel has ever been found in Colorado waters.   

CPW found a single adult zebra mussel on a piece of PVC pipe in the lake during routine invasive species sampling on September 14. According to a CPW press release, “Two CPW experts have independently confirmed the identification of the mussel through visual identification methods and genetic confirmation was also made on the sample.”  

Mussel larvae have been detected in eight different reservoirs in Colorado since 2008, according to CPW. The most recent was at Green Mountain Reservoir in Summit County in 2017, but that reservoir was declared mussel-free last year after three years of negative testing. The entire state was declared “mussel-free” in January 2021. 

The state ramped up its invasive mussel program in 2018 through passage of HB18-1008, the Mussel Free Colorado Act, by the General Assembly. The program requires all boat owners, whether Colorado residents or from out-of-state, to have an aquatic nuisance species tag prior to launching in any Colorado lake. The tag, which is $25 for Colorado residents and $50 for out-of-state visitors, pays for the state’s watercraft inspection and decontamination prevention system.