A live adult zebra mussel has been collected from the Colorado River below Utah’s Westwater Recreation Area near the Colorado border.
The invasive creatures are tiny but pose a major threat because they reproduce rapidly, can plug water lines, and are difficult and expensive to remove.
“If they get into water delivery systems, it will cost millions of dollars annually to remove them and keep the pipes free, which can result in higher utility bills,” said the Utah Division of Wildlife Resources in a release.
“They remove plankton from the water, which hurts fish species.
“Mussels can get into your boat’s engine cooling system. If they do, they’ll foul the system and damage the engine.”
In addition, dead mussels can pile up on beaches, their sharp shells cutting into the shoes of people walking there.
In 2025, an infestation was documented near Loma, Colorado, northwest of Fruita. The live mussel in Utah was found in September, according to the Utah Division of Wildlife Resources.
Once mussels are in a system, it’s easy for people recreating on water to spread them, or other invasive aquatic species, to other water bodies. All Utah boaters and river users are required to clean, drain, and dry all watercraft, whether motorized or not, when moving between water bodies.
The Utah Division of Wildlife Resources release is below:
For Immediate Release
Oct. 8, 2026
Live zebra mussel confirmed in Utah portions of the Colorado River
SALT LAKE CITY — Roughly a month after confirming zebra mussel DNA on the Utah side of the Colorado River, Utah Division of Wildlife Resources biologists collected a live adult zebra mussel below the Westwater Recreation Area on Tuesday, Sept. 22. Test results confirmed the finding on Oct. 7, and the DWR, the Utah Department of Natural Resources Law Enforcement Division and other partner agencies are responding to prevent the further spread of aquatic invasive species in the Colorado River.
Zebra mussels are an emerging threat in the Upper Colorado River Basin, with an established infestation documented near Loma, Colorado in 2025. Beyond disrupting aquatic ecosystems, zebra mussels threaten infrastructure by clogging pipes and present safety hazards for recreational users.
“Utah is dedicated to coordinating with our partners to contain and manage this aquatic invasive species threat,” DNR Law Enforcement Aquatic Invasive Species Statewide Operations Lt. Bruce Johnson said. “We need everyone’s help to protect our waterways. If you’re getting out on the water — whether on a boat, kayak or paddleboard — please make it a habit to clean, drain and dry your gear every single time. It’s a simple step that makes a huge difference.”
After the Colorado infestation, DWR began more extensive sampling for invasive mussels on the Utah side of the Colorado River in 2025 from the state line to Moab — areas that are unfortunately all downstream from the infestation. 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. Then the live adult zebra mussel was found during monitoring efforts in September.
The recent detection is a stark reminder of the serious nature of this threat. Once found in a system, it’s easier for recreators to spread mussels and other aquatic invasive species to other local waterbodies, imposing very serious issues on water infrastructure in a state reliant on irrigation. As a result, DWR and DNR law enforcement will remain vigilant and will continue to work with USGS, the National Park Service and the Bureau of Land Management to better understand the status of zebra mussels in the Colorado River within Utah and respond accordingly.
All river users in Utah — including those using nonmotorized watercraft such as canoes, paddleboards and rafts — are required to clean, drain, and dry their watercraft when leaving a waterbody. That includes removing debris, mud and water from the watercraft and trailer. Anyone using motorized watercraft are also required to take the mandatory mussel-aware boater program course and pay the associated aquatic invasive species fee for motorized boats. Drain plugs must also be removed before leaving a waterbody and transporting a watercraft within Utah.
“As some of the primary users of the Colorado River, nonmotorized boaters are our first line of defense in helping reduce the risk of transporting this species from the Colorado River to other waters in the state,” DWR Aquatic Invasive Species Coordinator Trina Hedrick said. “All boaters are required toclean, drain and dry all watercraft when moving between waterbodies to help prevent the spread of aquatic invasive mussels. We need everyone to get serious about this threat and help us stop the spread.”
Negative impacts of mussels
- They plug water lines, even lines that are large in diameter.
- If they get into water delivery systems, it will cost millions of dollars annually to remove them and keep the pipes free, which can result in higher utility bills.
- They remove plankton from the water, which hurts fish species.
- Mussels can get into your boat’s engine cooling system. If they do, they’ll foul the system and damage the engine
- When mussels die in large numbers, they stink and the sharp shells of dead mussels also cut your feet as you walk along the beaches.
Learn how to prevent the spread of invasive mussels and other aquatic invasive specieson the STD of the Sea website.
September’s rainfall continues to make headlines. Local weather expert James Andrus says that month’s nearly 5 inches of rain flipped the year-to-date precipitation in Cortez from 77 percent of normal at the end of August to 119 percent of normal by September’s end.
The 4.96 inches of rain that fell in September was 335 percent of the historic monthly average for that month.
If the half-inch of rain that fell on September 30, which technically is recorded with October’s totals, is added in, the month-long monsoon episode provided almost 5 ½ inches of rain
That represented 46 percent of the average annual rainfall for Corte of 11.79 inches, “so we received almost half of our annual precipitation in only one month!” Andrus said in an email.
Andrus said he would like to rename this year’s ninth month Soaktember.
