Staff with Colorado Parks and Wildlife’s (CPW) Aquatic Nuisance Species (ANS) team confirmed the existence of adult zebra mussels in the Colorado River and a nearby lake in Grand Junction. The Aquatic Animal Health Lab first confirmed that veligers, the microscopic larval stage of zebra mussels, had been discovered in West and East Lake, back in late August. Staff discovered the suspected adult zebra in the lake on September 2nd.
“While this is news we never wanted to hear, we knew this was a possibility since we began finding veligers in the river. I can’t reiterate this enough. It was because we have a group of individuals dedicated to protecting Colorado’s water resources that these detections were made. It is because of these same dedicated individuals and our partners that we will continue our efforts to understand the extent of zebra mussels in western Colorado.” – CPW Director Jeff Davis.
Surveys conducted in a side channel where water from the lake is released before flowing into the Colorado River also brought up suspect adult zebra mussels. Visual identification of the samples from the lake, channel, and river was first performed by ANS staff before the samples were sent to the Aquatic Animal Health Lab. Those samples were confirmed to be those of adult zebra mussels on September 8th.
This marks the first time that zebra mussels have been detected in the Colorado River. As such, from the 32 Road bridge downstream to the Colorado-Utah border, the Colorado River is now considered an “infested” body of water.
Other bodies of water confirmed to be infested by zebra mussels in Colorado are as follows:
- Highline Lake at Highline Lake State Park (2022)
- Mack Mesa Lake at Highline Lake State Park (2025)
- West and East Lake at the Wildlife Area Section of James M. Robb – Colorado River State Park (2025)
- Colorado River from 32 Road bridge downstream to the Colorado-Utah border (2025)
- Private body of water in Eagle County (2025)
“We won’t give up. Our priority remains utilizing containment, population management and education to protect the uninfested waters of the state.” – CPW Invasive Species Program Manager Robert Walters.
