“Be a pain in the ANS”— Colorado’s fight against invasive mussels

By Lyra Stone

When most people hear the word “mussel,” they probably think of seafood, not a growing environmental threat. But in Colorado, state officials are urging the public to pay attention to a different kind of mussel entirely: invasive freshwater species that can multiply rapidly, disrupt aquatic ecosystems, and damage critical water infrastructure.

Colorado Parks and Wildlife’s (CPW) aquatic nuisance species program focuses on preventing the spread of invasive organisms like zebra mussels, quagga mussels, and golden mussels. Zebra and quagga mussels have been present in the United States since the late 1980s, while golden mussels were first detected in California in 2024 and are spreading there quickly. Golden mussels are not currently known to be in Colorado, but officials say the threat is real.

These mussels pose serious problems for both ecosystems and people. They reproduce at extraordinary rates, with a single zebra mussel capable of producing tens of thousands of eggs in one spawning event and up to a million offspring in a year under the right conditions. They also feed on phytoplankton, an essential part of the aquatic food web, and cling to hard surfaces in dense clusters that can clog pipes, impair water delivery systems, and create expensive maintenance problems for facilities like dams and hydropower operations.

Because invasive mussels are so difficult to remove once they become established, Colorado’s strategy is centered on prevention. The state uses education, outreach, and a robust watercraft inspection and decontamination program to limit the spread from one waterway to another. Recreational boats are one of the biggest ways these species move, and in areas where zebra mussels have already been detected, such as the Grand Junction region, officials are working to contain them and prevent further spread.

The good news is that most of Colorado’s waters remain free of invasive mussels. Officials say that is no accident. They credit years of prevention work and public cooperation for keeping the problem from becoming much worse. And they say individuals can make a real difference by following one simple rule whenever they recreate near the water: clean, drain, and dry all gear and equipment between uses.

For Colorado, the fight against aquatic nuisance species is largely about stopping a costly and often irreversible problem before it takes hold. And for now, prevention remains the state’s strongest defense.

This story aired on the Morning Magazine, KGNU’s weekday morning show featuring in-depth discussions on local news issues. Click here to listen to other episodes of the Morning Magazine.