Eight federal government agencies have signed a memorandum of understanding to guide their response to invasive zebra mussels and quagga mussels in 19 Western states, including Colorado.

“Invasive mussels and other invasive species pose a significant risk to the Forest Service’s ability to meet our stewardship mission on national forests and grasslands, and across the landscape,” said Vicki Christiansen of the U.S. Forest Service. “Healthy streams, lakes, and rivers benefit Americans in a myriad of ways, from clean drinking water to important native species to diverse recreational opportunities.”

The U.S. Department of the Interior estimated that invasive mussels impose more than $1 billion in costs annually.  The mussels grow in clusters and displace native species, foul dams and clog boat engines.

“Many waterbodies in the West remain free of invasive mussels,” the department advised. But “with infestations in the Colorado River Basin including Lake Mead, Lake Powell, Lake Mojave and Lake Havasu, the risk is high that mussels may hitchhike on watercraft and be introduced to uninfested waterways.”

The agencies, which include the Army Corps of Engineers, the Bureau of Land Management, the U.S. Fish and Wildlife Service and the Forest Service, agreed in the MOU to encourage preparedness exercises, identify financial support and develop a list of experts for mussel response and mitigation.

As of Nov. 19, the U.S. Geological Survey identified clusters in Colorado on the Upper Arkansas River near Pueblo and in Grand Lake.