LAKE COUNTY – It isn't edible. It clogs pipes, disrupts a lake's food chain, fouls docks and ramps, causes millions of dollars in damage and threatens tourism. It could be coming to a lake near you.

What is it?

It's called the quagga mussel, and along with its cousin the zebra mussel, it could be one of the greatest concerns to ever face Clear Lake.

The county's Water Resources Division will go before the Board of Supervisors Tuesday with recommendations from the Clear Lake Advisory Subcommittee regarding how to deal with quagga and zebra mussels, said Pam Francis, deputy director of Water Resources.

That will include a request for a public outreach campaign – funded by transient occupancy taxes – to inform community residents and visitors about the importance of keeping the quagga and zebra mussels out of Clear Lake.

The quagga mussel is particularly pernicious, said Francis, outcompeting even its close cousin the zebra mussel.

The mussels originated in Russia and the Ukraine, according to the California Department of Fish & Game.

So far, Francis said, the mussels haven't arrived in Clear Lake.

She said the California Department of Food & Agriculture in February checked 10 sites near popular boat ramps around Clear Lake and didn't find the mussels. Nor were they found in Lake Pillsbury, Blue Lakes or other lakes and streams in the county.

The mussels are commonly found on concrete blocks and other rough surfaces where they can get a foothold, Francis explained.

Francis said the county has been following the spread of the mussels since about 2003.

The mussels move west

There has been a concerted effort by the federal government to prevent the mussels from moving west of the 100^th meridian, which is approximately the area of Oklahoma, Francis explained.

That effort seemed to be successful, she said.

That is, until, this January, when the mussels turned up in Nevada's Lake Mead, said Francis. That same month, they were found in Lake Havasu, at the Arizona-California border, which serves Southern California's Metropolitan Water District, according to Fish & Game.

The mussels travel in two ways, said Francis: through moving downstream in water bodies or through inadvertent human help.

In the case of humans, said Francis, the mussels attach to boats and trailers, which is how they travel to new bodies of water.

The microscopic mussel larvae – called veligers – can get into bilge water, fish tanks and bait buckets, Francis said. They also get into ballast water – which is carried in unladen ships to provide stability. That's how it traveled from the Baltic Sea to the United States, arriving in Michigan's Lake St. Clair in 1988 and Lake Erie in 1990, Fish & Game reported.

The costs to deal with the mussels have been astronomical, Francis said. “They create about half a billion dollars in damage, just in maintenance.”

She added, “Once you get them, you're sunk.”

Agencies assess the risks

The quagga and zebra mussels aren't identical, she said. Quaggas, she said, are “a little bit scarier,” because they can live in colder climates and can outlast zebra mussels.

The state Department of Food & Agriculture analyzed the risk levels for quagga and zebra mussel infestation of bodies of water around the state, Francis said.

Lake Tahoe, which has cold deep water and low phytoplankton levels, has a fairly low risk level, she said.

Clear Lake, Lake Pillsbury and Upper Cache Creek, however, are “at great risk,” Francis said, because of warmer, shallower water and other mussel-friendly conditions.

Although the mussels have no natural prey, they're easy to kill, said Francis. A little chlorine will do the trick, she said, as will letting boats and trailers sit out of the water for five days to dry out.

States such as Washington and Idaho have implemented stringent requirements to prevent the mussels from spreading there, said Francis. In the case of fishing tournaments, boats that come into those states from other areas must go through rigorous inspections and decontamination.

The California Department of Food & Agriculture has numerous checkpoints along the state's borders that stop boats coming in and inspect them, Francis said. The state also is working on a plan to fight the invasive pests.

Keeping the quagga and zebra at bay

The important next step is for the county to decide on a plan to prevent the mussels from making themselves at home in the county's lakes, said Francis. That effort will include public outreach, inspecting watercraft, and partnering with state and federal agencies to monitor the issue.

Water Resources has a draft plan to keep the mussels out of Clear Lake, said Francis, which they'll take to the Board of Supervisors Tuesday.

A copy of the plan explains that if the mussels infested Clear Lake, the consequences would include disruption to fishing and the food chain, docks and ramps being ruined, encrusted boats and clogged engines, beaches littered with sharp and smelly shells, and clogged drinking water and other intake pipes, resulting in increased maintenance costs.

Francis said Water Resources isn't asking the Board of Supervisors to adopt the plan right now, but to look at it and offer guidance on how they want county staff to move forward. “We need to prevent these things from getting here,” she said.

With more fishing tournaments and competitions such as BoardStock taking place on the lake, Francis said stringent decontamination requirements will become necessary. Those would include requiring boats to dry out for several days or go through a wash station. An infrastructure to cover those requirements will need to be put in place, she said.

Rather than spending millions later to try to get rid of the invasive mussels, Francis said, “I would rather spend a lot of money right now, up front, preventing them.”

The Water Resources Division's Web site, watershed.co.lake.ca.us, will include more information about how to prevent quagga and zebra mussels from getting into Clear Lake, Francis said, with a major site update expected to be live in June.

E-mail Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it..

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