UPDATE: Colorado Parks and Wildlife has announced the discovery of juvenile zebra mussels in the Colorado River and Government Highline Canal. The free floating planktonic babies, also known as veligers, were discovered early this month. A sample was taken from Highline Canal near Clifton on the 1st and the lab reported the discovery to Invasive Species Program Manager, Robert Walters. Then, on July 11th, samples from the Colorado River were also confirmed to have the presence of Zebra Mussel DNA. The presence of these invasive mussels in our waterways threatens irrigation, drinking water, and infrastructure. CPW strongly encourages anyone recreating on the water this summer to clean, drain, and dry any crafts and equipment before and after use. END
Aquatic Nuisance Species, or ANS for short, are a problem all over the North American West. Preventative measures have stopped invasive species from entering Colorado for years, but now Colorado Parks and Wildlife is going on the offense against invasive mussels at Highline Lake and Ruedi Reservoir.
Before any motorized boat gets into the water, it must pass inspection. Motorized boats and their trailers can carry water and mud for miles. possibly bringing microscopic baby zebra and quagga mussels with them. Madeline Baker, an invasive species specialist for Colorado Parks and Wildlife, is part of a statewide effort to prevent our state's lakes from going the way of Lake Powell.
"We have staunch decontamination procedures. That really kind of focus on evaluating that risk of where has the boat been, how much water could they be carrying? And, um, if we do determine there to be risk, those boats are decontaminated with hot water before they launch in Colorado. So, no bleaches, soaps or chemicals, just hot water is enough to kill them and lots of folks believe that these infestations are inevitable, but I believe that if they were, they probably would have already happened, right? Our efforts have to be worth something."
Inspectors at Ruedi Reservoir prevented two mussel fouled boats from entering the water on the first day of the 2024 season. The only lake in Colorado that has detected adult zebra mussels is Highline, which is currently off limits to motorized vessels. Baker notes that conditions at Lake Powell, which straddles the border of Arizona and Utah, are one of the largest risk factors for Colorado.
"80 percent of what we call mussel boats or mussel fowl craft are originating from Lake Powell. It's just the nearest in vicinity to Colorado when it comes to infested bodies of water, and lots of folks in Colorado love recreating there. So 80 percent of the mussel fouled craft we get are from Lake Powell. So that means that the number of mussel boats we intercept is largely dependent on things like the water levels at Lake Powell. So when the water levels are low. There's a lot more mussels that are exposed on the canyon walls and on the shorelines. It really depends on what the water levels are like at Lake Powell, what the snowfall levels are like in the winter, and all sorts of things that you wouldn't even think anything to do with aquatic nuisance species."
While vigorous preventative measures still prove effective, CPW is being forced to pivot to eradicate the presence of adult mussels in Highline Lake. The lake will be drained this fall after the growing season. Baker says that if it had to be any lake, she's glad it's Highline.
"The only reason that eradication is even a possibility is because it's on Colorado Parks and Wildlife owned property and it is fed [by] and the outflow are both man made structures so we can turn off the water to highline and kind of isolate it as a stagnant pool and then do chemical treatments or drain it as we choose, but there's lots of bodies of water in Colorado that are just open bodies of water that are fed by rivers that flow through them that we cannot stop or impede. So, this sort of eradication is certainly not possible anywhere, which is why we focus so heavily on prevention."
Colorado is a headwater state for its drier neighbors like Utah and Arizona, meaning if mussels prevail here and impact infrastructure, hundreds of thousands could feel the effects. Responsibility for protecting Colorado's waterways and native species doesn't end with motorboats. Paddleboarders, kayakers, fishers, and anyone who recreates in water can play a part.
"The biggest thing that we like to kind of use to educate folks is clean, drain, and dry. So even if you have something that's exempt from our inspections, like a paddleboard, or a kayak, or a raft, you can still do your part by making sure that there is no mud, water or plant material on that craft as you're transporting it."
More information about aquatic nuisance species, the dangers they pose and how to help can be found on the Colorado Parks and Wildlife website.
