ROUND HILL PINES BEACH, Nev. - Nevada and California agreed Thursday to jointly mount a counterattack against invasive species that pose an increasing threat to Lake Tahoe's azure waters.
Gov. Jim Gibbons and California Secretary of Natural Resources Mike Chrisman signed the agreement during an environmental summit that annually brings together scientists, politicians, federal land managers and conservationists to get updates on the condition of the lake and new potential sources of harm to its famed clarity.
"Those of us in the political arena come from many different political points of view but we come together when we talk about Lake Tahoe," said Sen. Dianne Feinstein, D-Calif.
"That little line that goes down the middle of the lake between our two states is not a line that divides us, it is a line that joins us," added Gibbons, a Republican.
While catastrophic wildfires, air pollution and erosion
continue to pose threats to the lake, new research shows a major infestation of nonnative Asian clams could cause even more trouble.
"This is another battle," said Sen. John Ensign, R-Nevada, this year's formal host of the event. "It seems like every time we start having a victory we have another battle come along."
The dime-sized clams are believed to be linked to a major algae bloom last summer and experts said they could help other invaders, quagga and zebra mussels, successfully establish at the lake. Densities of clam beds have increased dramatically since the first discovery in 2002.
"Invasive species are one of the greatest threats to Lake Tahoe and the Tahoe basin," said Allen Biaggi, head of the Nevada Department of Conservation and Natural Resources. "If invasive mussels get a toe hold in Lake Tahoe, it will only be a matter of time before they get into the Truckee River and ultimately Pyramid Lake."
Sudeep Chandra, an assistant professor specializing in research into the impact of land changes on freshwater ecosystems at the University of Nevada, Reno, said the joint agreement is a "great step" toward protecting the lake.
The management plan will include efforts to prevent new introductions of species to the Lake Tahoe basin, limit the spread of existing populations and "abate the harmful ecological, economic, social and public health impacts" resulting from such species.
"Once established in the lake, invasive species can alter the lake's biodiversity, change the lake's clarity and affect our recreational opportunities," Chandra said.
In addition to the clams and mussels, nonnative species in the lake include warm water fish like bluegills and largemouth bass as well as plants like the Eurasian watermilfoil. At least 20 nonnative species have been found, Chandra said.
"The good news is that many of them are in the early stages of advancement," he said. "Our research has shown you can manage these populations if you get to them immediately."
A study by scientists at the University of California-Davis released this week found up to 3,000 Asian clams per square meter in the lake's shallow waters on the southeast shore between Zephyr Point and Elk Point. Ensign toured the area in a boat Thursday morning.
"It really was shocking to see the numbers and see the dead shells that have been laid down," he said.
Feinstein, who has visited the lake for 60 years and spent many childhood summers there at camps, showed off a pair of Asian clam earrings.
"When you look at them they are a thing of beauty. But if you think of what they can do to foul your water, kill algae, put it up on the beach and have a rotting mess, you won't appreciate the Asian clam," she said.
"Without direct specific action, we could lose this lake faster than anyone believes," she said. "If we don't get a stranglehold on them, they will get a stranglehold on this lake."