Utah Finds Zebra Mussel Genetic Traces In Colorado River Water Samples
For the first time, fragments of zebra mussel DNA have been detected in the Colorado River in Utah, prompting the Utah Division of Wildlife Resources and its partner agencies to remind boaters and other watercraft users of the importance of preventing the spread of aquatic invasive species.
The discovery does not necessarily mean live zebra mussels are present in the river. Environmental DNA, or eDNA, can indicate that an animal is present somewhere upstream, but the test cannot determine whether live mussels are established at the location where the sample was collected.
Still, the detection is an important warning, particularly because zebra mussels are an emerging threat in the Upper Colorado River basin. An established infestation was documented near Loma, Colorado, in 2025.
All Watercraft Are Subject To Clean, Dry And Drain
“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 in a press release. “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 DWR began sampling for invasive mussels in the Colorado River in 2025, covering the river from the Utah-Colorado state line to Moab. In June and July, an environmental DNA autosampler was placed near the Potash Boat Ramp, about 14 river miles downstream from Moab. The device collected water samples each day, which were analyzed by the U.S. Geological Survey for zebra and quagga mussel DNA.
Four of 22 samples collected during that period tested positive for zebra mussel DNA. However, eDNA and veliger samples collected this spring and summer from other locations along the Colorado River in Utah have not tested positive.
DWR and the Utah Division of Law Enforcement will continue working with the U.S. Geological Survey, National Park Service and Bureau of Land Management to determine what the detection means and better understand the status of zebra mussels in the river.
For Utah water users, prevention remains the most important defense. All river users, including people using canoes, paddleboards and rafts, are required to complete Utah’s annual mussel-aware boater course. Anyone launching a motorized boat in Utah must also pay the annual aquatic invasive species program vessel enrollment fee.
Read More: Boat Inspections At Lake Powell To Stop Mussel Spread
DWR Sportfish Coordinator Trina Hedrick said nonmotorized boaters are particularly important in preventing the spread of the species. “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.”
The message is simple: clean, drain and dry every watercraft before moving to another body of water. That small effort could help keep Utah’s other rivers, reservoirs and lakes free of an invasive species that could prove extremely difficult to remove once established.
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Gallery Credit: Jess Rose
