Pilot program would remove invasive clams

SOUTH LAKE TAHOE, Calif. " With California officials vowing to take a closer look at the threat invasive species pose to the state, a pilot program to remove clams that have already invaded Lake Tahoe is set to begin as early as next week.

The Tahoe Resource Conservation District and Tahoe Regional Planning Agency are spearheading the more than year-long effort to find the most effective way to control the spread of Asian clams in Lake Tahoe.

The program will include suction dredging and the placement of plastic sheets on the bottom of Lake Tahoe at two 160-by-60 foot test sites at Regan Beach and Marla Bay, said TRCD's Interim Invasive Species Program Manager Nicole Cartwright.

The plastic sheets are designed to deprive the clams of nutrients, and the dredging will be used to remove living clams and the shells they leave behind when they die.

The two strategies will be used individually and in combination at the test sites to determine the best method to prevent the spread of the clams and reduce their impacts on Lake Tahoe, Cartwright said.

Residents and visitors can expect to see several boats " including one with a crane " near the test sites for several days at a time through the length of the program, Cartwright added.

The program is expected to cost about $500,000 and is being paid for mostly through federal funds, Cartwright said.

Although the full extent of the clams in Lake Tahoe is unknown, an April survey by UC Davis Tahoe Environmental researchers found living clams or shells at seven out of 10 sites examined at Lake Tahoe's South Shore, with some of the densest patches found north of Nevada Beach.

The clam species have the potential to clog drinking water intake pipes and litter beaches with sharp shells, according to the TRCD.

Researchers have also found a connection between clam beds and an algae bloom in Marla Bay this summer, and are concerned increased calcium levels created by the clams could provide a foothold for other invasive species.

"That could open the door for the quagga and zebra mussels," said TRPA spokesman Dennis Oliver. Officials began mandatory inspections of boats launching into Lake Tahoe this summer to keep mussels out of the lake.

Neither the clam species or the mussel species have been successfully eradicated in other areas of the country, Oliver said.

The zebra mussel, a relative of the quagga that plagues the Great Lakes, cost the power industry $3.1 billion to fight in the 1990s, state officials say. Now the Ukranian quagga " which is already established in lakes Mead and Havasu, where they damage hardware in Hoover Dam's hydroelectric operations " has migrated to the Colorado River Aqueduct.

Mussels are transported on boat hulls and in ballasts, often by recreational users unaware of the danger posed by the fingernail-sized mollusks.

Controlling quagga mussels will be one focus for the California Invasive Species Council, the formation of which was announced this week. The council aims to streamline duplicated efforts.

For instance, the California Department of Food and Agriculture, which inspects border crossings for pests on fruits and vegetables, also could check boats for quaggas, a task now performed by the California Department of Fish & Game.

- The Associated Press contributed to this report.

contributed to the report.

"This is about most efficiently using our resources," said California's Department of Food and Agriculture Secretary, A.G. Kawamura, who will head the effort.

The council will collaborate with scientists, environmental groups, landowners and industries harmed by invasive species. The goal is a "rapid response plan" to focus attention from all the agencies on the most urgent species poised to cause the greatest economic, public health or environmental hardship.

"I think back to the olive fruit fly and how we had a chance to eradicate it two decades ago, but we walked away," Kawamura said, referring to the pest that now exists in 41 counties. "These are the kinds of challenges we are going to face more and more."

" The Associated Press contributed to this story.