Anti-mussel research won't change boat rules at Lake Tahoe

STATELINE (AP) - Environmental regulators at Lake Tahoe are encouraged by new research on bacteria that kills zebra and quagga mussels. But they says they don't intend to stop the mandatory boat inspections they credit with keeping the invasive species out of Tahoe's azure waters.

Daniel Molloy and Denise Mayer, two researchers for the New York State Museum, say the bacteria strain Pseudomonas fluorescens has been shown to successfully kill zebra and quagga mussels without killing other native species in the ecosystem.

"The 'eureka' moment did not come, interestingly enough, when we discovered the bacteria could kill zebra and quagga mussels, but came when we discovered the lack of sensitivity among non-target species," Mayer told the Tahoe Daily Tribune.

Scientists have found plenty of agents capable of killing the mussels, but most kill everything else in the ecosystem too, she said.

To date, tests on Pseudomonas fluorescens have been limited to attacking mussels in pipes and industrial equipment, but new research is beginning to see if it could be effective in open waters.

The two dreaded mussels native to Eastern Europe can cover beaches with sharp shells, overwhelm a lake's natural ecosystem and cause blooms of noxious algae.

The Tahoe Regional Planning Agency has been concerned about the threat since the quaggas first turned up in Lake Mead in 2007. They since have spread to other water bodies in Southern Nevada and California.

Zebra mussels were found in 2008 in California's San Justo Reservoir about 250 miles from Lake Tahoe, but so far neither invader has been detected in the lake.

Marrone Bio Innovations, based in Davis, Calif., is in the process of getting federal approval of first commercial formula using the bacteria discovered by Mayer and Molloy.

Zequanox - the name of the product that combines P. fluorescens with other naturally occurring ingredients such as sugar - could be approved in the first quarter of 2011, with sales commencing later in the year, said CEO and founder of the company Pam Marrone.

"We've been working on Zequanox for the past five years," Marrone said. "We've had to find a way to grow it large-scale, commercial size, so customers could use it."

Marrone tested the formula with Power Generation, a Canadian power supply company, and the U.S. Bureau of Reclamation. The tests determined Zequanox can kill mussel populations attached to pipes and other industrial material.

Marrone has begun testing if the product could be used in open-water scenarios. In a quarry infested with zebra mussels, Zequanox showed "some effect," Marrone said.

TRPA, the bi-state federal regulatory panel charged with protecting the lake, launched its lake-wide boat inspection program three years ago in an effort to prevent aquatic invasive species from entering into the waters of Lake Tahoe.

Ted Thayer, manager of the agency's Aquatic Invasive Species Program, said the discovery of the bacteria's new use is "encouraging" and he's hopeful it will someday prove effective in open-water situations.

"It's exciting to have the tools available should the lake have an introduction (of non-native mussels)," Thayer said.

"It would be great if they can perfect it to the point where it could be used in a place like Lake Tahoe," he said, "but right now, there is no change to our inspection program."

In addition to the mussels, Thayer said the inspection program is designed to prevent a variety of species from entering the lake, including noxious weeds and non-native invertebrates.


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