Fragments of zebra mussel DNA were recently detected in the Colorado River in Utah for the first time, and the Utah Division of Wildlife Resources and partner agencies are reminding boaters and other watercraft users to remain vigilant in preventing the spread of aquatic invasive species.
Zebra mussels are an emerging threat in the Upper Colorado River basin, with an established infestation documented near Loma, Colorado in 2025. The detection of environmental DNA in the water only indicates the presence of an animal somewhere upstream — it does not confirm that live mussels are present.
"Once established, zebra mussels can clog pipes and infrastructure, create recreation hazards on rocks and beaches, and alter ecosystems," Utah Department of Natural Resources Law Enforcement Aquatic Invasive Species Statewide Operations Lt. Bruce Johnson said. "It is critical for anyone who uses boats, paddleboards, kayaks and any other watercraft to adhere to all the laws and to clean, drain and dry their watercraft in order to prevent these aquatic invasive species from spreading further into Utah."
The Utah Division of Wildlife Resources began sampling for invasive mussels in the Colorado River in 2025 from the state line to Moab, Utah.
In June and July, an environmental DNA autosampler was deployed at a new location near the Potash Boat Ramp, approximately 14 river miles downstream of Moab. The sampler collected daily water samples, which were then analyzed by the U.S. Geological Survey for zebra and quagga mussel DNA. Four of 22 samples came back positive for zebra mussel DNA during this period. Environmental DNA and veliger (the larval stage of the mussel) samples collected this spring and summer from other locations along the Colorado River in Utah did not come back positive.
The recent detection is a stark reminder of the serious nature of this threat. DWR and the Utah Division of Law Enforcement will continue to work with the U.S. Geological Survey, the National Park Service and the Bureau of Land Management to better understand the status of zebra mussels in the Colorado River within the state.
All river users in Utah — including those using nonmotorized watercraft such as canoes, paddleboards, and rafts — are required to complete Utah's annual mussel-aware boater course, which is a great opportunity for all boaters and floaters to learn about this invasive species, how they are problematic, and how to help protect all of Utah's waters from this threat.
Anyone who wants to launch a motorized boat in Utah must also pay an annual aquatic invasive species program vessel enrollment fee. This fee helps the DNR operate the state's program and keep AIS from spreading around Utah.
"As one of the primary users of the Colorado River, nonmotorized boaters are our first line of defense in helping reduce this risk of transporting this species from the Colorado River to other waters in the state," DWR Sportfish Coordinator Trina Hedrick said. "All boaters are encouraged to clean, drain, and dry all watercraft when moving between waterbodies to help prevent the spread of aquatic invasive mussels. There is no time like right now to get serious about this threat."
Learn more about how to prevent the spread of zebra mussels and other aquatic invasive species on the STD of the Sea website.