Colorado Parks and Wildlife provides update on increased zebra mussel sampling efforts in the Colorado River

Rachael Gonzales
Northwest Region Public Information Officer
970-773-8587 / [email protected]
Twitter: @CPW_NW Colorado Parks and Wildlife provides update on increased zebra mussel sampling efforts in the Colorado River

GRAND JUNCTION, Colo. — Colorado Parks and Wildlife (CPW) staff found an additional single zebra mussel veliger in the Colorado River during increased sampling efforts near New Castle, Colo. in early June.

“Although not ideal,” said Invasive Species Program Manager Robert Walters. “These results provide us with critical information as we continue working closely with our partners to protect our natural resources and infrastructure crucial to the Western Slope, including our goal of identifying the source.”

On June 9, CPW Aquatic Nuisance Species (ANS) staff collected plankton samples from several locations along the Colorado River between Glenwood Springs and Parachute as part of an increased sampling effort. On June 17, ANS laboratory technicians identified a single suspected zebra mussel veliger in a sample collected near the Grand River Park in New Castle. The sample was sent to the CPW Aquatic Animal Health Lab (AAHL) for genetic confirmation. On June 19, the lab confirmed the samples were positive for zebra mussel DNA.

Since sampling efforts restarted in May, CPW has collected 150 water samples from various locations in the Colorado River from Glenwood Springs to the Colorado-Utah border. This is the first detection of a zebra mussel veliger in the Colorado River since the initial discovery of zebra mussels in the Government Highline Canal and Colorado River in July 2024. No adult zebra mussels have been found in the Colorado River to date.

CPW ANS and Northwest Region Aquatics staff, along with our partners at the U.S. Fish and Wildlife Upper Colorado Native Fish Recovery Program and the U.S. Bureau of Reclamation, will continue sampling efforts in the Colorado River and associated waterways to locate the source of the zebra mussel veligers.

In addition to sampling, CPW continues the increased education and outreach efforts on the Colorado River, including encouraging voluntary watercraft inspections.

CPW also encourages those who use water pulled from the Colorado River and find any evidence of mussels or clams to send photos to [email protected] for identification. It is extremely important to accurately report the location in these reports for follow-up surveying.

Be a Pain in the ANS: Clean, Drain and Dry your vessels and gear
Everyone has a part to play in preventing the introduction and spread of invasive species in Colorado. Simple actions, like cleaning, draining and drying your motorized and hand-launched vessels — including paddleboards and kayaks — can make a big difference to protect Colorado's waters. These steps are crucial in helping prevent situations similar to the recent one at Highline Lake.

Anglers are also encouraged to clean their gear between each and every use, keeping it free of mud and plants. By cleaning, draining and drying your angling gear, you can avoid unknowingly moving an invasive species from one body of water to another or even between different stretches of the same river, which can cause a domino effect of invasion with irreversible ecological damage.

Learn more about how you can prevent the spread of aquatic nuisance species and tips to properly clean, drain and dry your boating and fishing gear by visiting our website. Tips for anglers and a map of CPW’s new gear and watercraft cleaning stations are available here.

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PHOTO CUTLINE:
BOTH IMAGES: Microscopic images of a single zebra mussel found in the Colorado River near New Castle during sampling efforts by CPW on June 9.