Quagga Mussels Threaten Utah

Destructive mussels only miles from Utah's border

August 9, 2007 news release: Invasive mussels detected in Lake Powell

Utah is working to protect its borders from an invasive, alien species. If this species sneaks into the state, it will change the way many Utahns lives their lives.

This invader is called a quagga mussel. Quagga mussels and their close relative, the zebra mussel, are freshwater, bivalve mollusks that are similar to a clam.

Quagga mussels aren't native to North America, but they've found their way to the continent and have invaded many of the waters east of the 100th meridian (an imaginary line that divides the eastern part of the United States from the western part).

Recently, quagga mussels were found in the Lower Colorado River drainage, including lakes Mead, Mojave and Havasu in Nevada.

Quagga mussels usually have a dark and white (zebra-like) pattern on their shells. When they're fully grown, they're only about 1/4 of an inch across.

That may not make them sound like a serious threat, but they are.

Boat motor covered with Quagga Mussels
This boat motor is covered with quagga mussels. These prolific mussels can cover a submerged item in a matter of days.

Photo courtesy of Wayne Gustaveson

Tiny and Destructive

Quagga mussels cluster in tremendous numbers. Clusters of more than 700,000 quagga mussels per square meter have been found in the Great Lakes.

Quagga mussels often attach themselves to hard surfaces, such as rocks, pipes, cement, anchors, cables, other quagga mussels and even the bottoms of boats. In fact, hitchhiking on the hulls of fishing and ski boats is one of their favorite ways to move from one lake to another.

Mussels are filter feeders. They draw water through their body and then use a filter inside their bodies to capture minute particles, which they digest. The same action that brings water and food into their bodies also carries waste out of their bodies and into the water around them.

Quagga mussels can reach higher densities by clinging to intake pipes where the water is always moving. Moving water provides them with fresh water to filter their food and carry away their waste.

Under these conditions, quagga mussel concentrations can become enormous. These concentrations restrict the amount of water that can flow into treatment plants and hydroelectric facilities.

If allowed to infest and multiply in the water storage reservoirs that are so common in Utah, the effects will be disastrous. It can cost millions of dollars to remove large concentrations of mussels from pipes and restore proper water flows.

Because quagga mussels are filter feeders, they utilize the plankton that represents the base of the aquatic food chain. Quagga mussels are efficient feeders, and few animals can compete with them for food or space. Given enough time, quagga mussels out compete other aquatic species in the waters they invade, including insects, crayfish and fish.

Once they've displaced these other species, they become the dominant species in the aquatic biomass. That means the number of sport fish in Utah, such as bass and trout, and the state's native fish, many of which are on the federal Endangered Species list, will be reduced in number or completely replaced by quagga and zebra mussels.

How They Got Here

Quagga and zebra mussels are native to Europe and Asia. They were found in the United States in the mid-1980s, when they were introduced into the Great Lakes region. They probably hitched a ride to the Great Lakes in the ballast tanks of commercial ships.

These mussels quickly spread throughout the eastern part of the country, but they were not found in the West until January 2007 when they were discovered in Lake Mead.

With mussels so close to Utah, it's no wonder state and federal officials are taking actions to keep them from crossing Utah's border.

How You Can Help

You can help keep quagga mussels out of Utah by taking the following actions when moving aquatic recreational equipment from one water to another:

"There is no effective way to remove mussels from a water body once they've become established," says Clay Perschon, special aquatic projects coordinator for the Division of Wildlife Resources.

"If mussels become established, they can damage your boat, destroy the fishery at the water and can result in spending of millions of dollars to clean pipes."

"If you're a boater, your cooperation is absolutely essential to keep mussels from infesting Utah," Perschon says. "We need your help desperately to keep quagga mussels out of Utah."

For detailed instructions on how to clean your boat, please visit the following Web sites:

Contact: Lynn Chamberlain, DWR Southern Region Conservation Outreach Manager (435) 865-6114 or (435) 865-6100, or Mark Hadley, DWR Conservation Outreach Specialist (801) 538-4737