Biologists have discovered a live adult zebra mussel in the Utah portion of the Colorado River, raising concerns about the spread of the invasive species within the state. The mussel was found on September 22 below the Westwater Recreation Area. This discovery follows about a month after testing had initially detected zebra mussel DNA in the water in Utah, according to a news release from the Utah Division of Wildlife Resources. The division received confirmation Wednesday that the live mussel had indeed been found downstream of an earlier infestation near Loma, Colorado, which was detected in 2025.
The Utah Division of Wildlife Resources has increased its testing efforts for zebra mussels in the Colorado River, specifically between the state line and Moab. This ramped-up testing began after the Loma infestation was identified. The division warns that once an invasive species is detected, the risk of an outbreak grows due to people recreating in the river and potentially unknowingly transporting these organisms to other waterbodies on their watercraft.
Zebra mussels, though small, pose a significant threat, especially in Utah, a state heavily reliant on irrigation. These invasive mussels can spread into water lines, leading to clogged pipes that require millions of dollars to remove. They also damage boat engines and disrupt aquatic ecosystems by removing plankton from the water, which impacts food supplies for fish. The shells of zebra mussels are razor-sharp and can cover beaches, damaging natural environments.
To combat this threat, Utah law mandates strict requirements for all vessels entering the state's waters, encompassing everything from boats and jet skis to kayaks and paddleboards. These watercraft must be cleaned, dried, and drained when they are removed from the water, a requirement that also extends to water and mud found on their transporting trailers, as stated in the news release.
Additionally, recreators must complete a mandatory mussel-aware boater program course. They are also required to pay the state’s aquatic invasive species fee and remove drain plugs while transporting their watercraft. Across the state, inspection and decontamination sites have been established to check for zebra mussels and other invasive species, including quagga mussels and Eurasian watermilfoil. During the recent Labor Day weekend, state agencies conducted inspections on 9,418 watercraft.
The DWR notes that quagga mussels, another type of invasive mussel, have been identified for a fourth consecutive year in Idaho’s Snake River. However, their numbers have reportedly decreased following years of aggressive treatment efforts. For individuals seeking more information about invasive species, including a list of decontamination stations available across the state and the specific requirements for watercraft, Utah’s "STD of the Sea" website offers resources.
