Lake divers have found no more quagga mussels, but state officials say they will continue to hunt for the invasive, pipe-clogging mollusks they fear could wreak havoc with water lines supplying Southern California.
LOS ANGELES -- Lake divers have found no more quagga mussels, but state officials say they will continue to hunt for the invasive, pipe-clogging mollusks they fear could wreak havoc with water lines supplying Southern California.
Quagga mussels were found earlier this month at Lake Mead in Nevada and Lake Havasu, near the Metropolitan Water District of Southern California's Whitsitt intake facility. The discoveries launched a wider search for infested reservoirs and pipelines in California that are connected to the Colorado Aqueduct, which supplies water to an estimated 18 million people.
Officials have searched the inlet tower of Diamond Valley Lake near Hemet, Lake Matthews in Riverside County and Lake Skinner near Temecula. So far, no additional mussels have been spotted.
"Although it shows adult mussels are not currently in the area of the reservoirs that we're checking, it doesn't mean the quaggas are not in the lake because of the larvae," said MWD spokesman Bob Muir. "But this certainly is encouraging."
The mussels can choke pipelines and threaten native species of fish by competing for their food.
"I suppose when people ask what level of concern we have, it's high and what level of effort we're putting in, it's considerable," said Mic Stewart, the MWD's manager of water quality.
Officials will shut down the entire aqueduct, which provides water to Los Angeles and San Diego, for three weeks in March to dry out the canals and will use chlorine to kill the mussels. Even so, because the freshwater mollusks multiply rapidly -- with a single female laying as many as 1 million eggs -- it is unlikely that action will completely rid the state of the hardy mollusks.
"They're extremely difficult to eradicate," Muir said. "It's more a matter of trying to control them."
The invasive mussels likely hitched a ride on a private boat from Michigan's Great Lakes to Lake Mead and Lake Havasu. Because the mussels are young -- between 6 months to 2 years old -- officials are hopeful that they can manage the situation.
Divers in California, Arizona and Nevada continued the search in a coordinated multi-agency effort this week.
The California Department of Fish and Game and the water district launched a public information campaign to tell boaters how to recognize and deal with the mussels. They have also set up checkpoints in Yermo, Needles and Blythe where boats and trailers are being searched for mussels. Similar searches are also taking place at Lake Skinner and Diamond Valley Lake.
The freshwater mollusks were accidentally introduced to the Great Lakes region in the ballast of ships from eastern Europe and the Ukraine. They can plug pipes up to 12 inches in diameter, and restrict flow in larger pipes. The colonies can also speed corrosion of pipes and other underwater infrastructure.
Until the quagga mussels were found this month in Lake Mead, they had not been spotted in the western United States.
"Depending on if they become established in California, they can be devastating to the state's environment and economically because of the effort necessary to try and eradicate them," said Troy Swauger, spokesman for the state's Department of Fish and Game. "At this point we're not sure if they are seriously established in the state and we're not sure if it would be possible to eradicate them."
On the Web: http://www.dfg.ca.gov/
Source: Associated Press