Zebra mussel found in California reservoir
Authorities investigate appearance of invasive mollusk in San Benito County. Prolific creatures can clog waterways and pose a threat to fish populations.
The zebra mussel that has wreaked havoc in waterways around the nation has been found in California, dismaying state and federal water officials who hoped to prevent the fast-spreading mollusk from reaching the West Coast.
State officials do not know how the mussel traveled west of the Rockies, although they suspect it may have hitched a ride on a recreational boat transported by trailer.
Dozens of zebra mussels turned up in the last 10 days in a Hollister-area reservoir that serves growers and residents in San Benito County, known for its walnut and apricot orchards. County officials there worry that the mussel will clog irrigation lines and pumps in a region that has already been hit hard by state water shortages.
The zebra mussel, like its close relative the quagga mussel, is a European native that infested the Great Lakes and other waterways in the last two decades, causing hundreds of millions of dollars in damage. Both types of mussels can alter the food chain dramatically and cause steep declines in fish populations, according to government and academic scientists who have studied their spread.
The quagga mussel, which made its first western appearance in Lake Mead last January, has already spread through the Colorado River Aqueduct to reach several Southern California reservoirs.
"It's not good news. If they're as invasive as they say, it could be a nightmare for our infrastructure," said Arman Nazemi, assistant San Benito County public works director, who heard last week that a fisherman found a zebra mussel in San Justo Reservoir.
There is no definitive way to eradicate the zebra or quagga mussel, state officials said.
"Once they're in a waterway, there's not much we can do," said Alexia Retallack, spokeswoman for the California Department of Fish and Game, which announced the zebra mussel's discovery Tuesday. "They're prolific breeders. A female can produce 40,000 eggs in a single spawning, and over a season about a million. That's a lot."
Myriad questions surround the zebra mussel's discovery in San Justo Reservoir, which is normally open to recreational boaters but has been closed to them since the mussel was found.
"We want to know how widespread are they. Is this an isolated occurrence, or is the reservoir full of them?" Retallack said.
