FALLON, Nev. — After months of testing, the Bureau of Reclamation and Nevada Department of Wildlife last week announced quagga mussels have been linked to Lahontan Reservoir.

The BOR found quagga veligers, or larvae, during testing in April, and subsequent tests have indicated the destructive mussels are present, said Karen Vargas, aquatic invasive species coordinator for NDOW.

“We're saying Lahontan is positive for quagga larvae,” Vargas said. “We're very concerned. The focus will be educating the public to clean, drain and dry their boats.”

Three samples each taken at Lahontan and Rye Patch in April returned positive from the BOR's lab in Denver. Vargas said the BOR used DNA and specialized microscope testing to determine if the suspected larvae were quaggas.

Vargas added Rye Patch Reservoir near Winnemucca was listed as “suspected” after rounds of testing. Results from Rye Patch were positive except for one negative DNA sample.

Lab results for Pyramid Lake, Wildhorse Reservoir, the Ruby Marshes and various lakes in the Sierra came back negative, Vargas said.

However, Vargas said Lahontan has tested negative the past two months, which may mean the quaggas won't adapt to the water. She added if conditions at Lahontan and Rye, such as water levels, temperature and calcium levels — among others — aren't conducive to quaggas, the larvae may not attach.

“There's the possibility they won't acclimate to the waters at Lahontan and Rye Patch,” Vargas said. “Whether that happens or not, we don't know. Our approach is we are looking at it that they are there.”

She added it takes about two to three years for quagga populations to dramatically increase.

Quagga mussel

The quagga mussel, according to the United State Geographical Survey, is a round freshwater mollusk about 1.5 inches in length. The mussels typically have dark rings on the shell and color patterns can vary from black, cream or white.

Quaggas are from the Ukraine and were introduced into the United States in the Great Lakes in 1989. The mussels have been identified in 16 states, with the greatest populations in the Great Lakes.

Ted Thayer, aquatic invasive species project manager for the Tahoe Regional Planning Agency, in addition to numerous sources for this story, said the quaggas are filter feeders.

The mussels can crash the food web and fisheries by removing all the food smaller fish rely on. Thayer said Lake Mead in Southern Nevada and Arizona has had issues with stripers.

In addition to hoarding plankton, the excess release of excrement from mussels causes issues as well. Thayer said the mussels are known to be associated with blue-green algae and acidobacteria, which impact the ecology and taste and color of drinking water.

“There (are) quite a few impacts of these mussels,” Thayer said.

Andrew Munoz, public affairs officer for the U.S. National Parks Service at Lake Mead, said the mussels can survive in any moist area. The unofficial motto Munoz, Thayer and others preach to boaters is “Clean, drain and dry.”

After a day on the lake, Munoz recommended opening all the boat hatches, make sure the bilge is dry, pull out the bolt plug and check for standing water. He added the larvae can attach to the hull or exterior of boats.

“A lot of times people with throw stuff into their bilge like life jackets or other materials that can absorb water,” Munoz said. “That dampness can also harbor the veligers (larvae).”

Hoover Dam/Lake Mead

Rose Davis, a BOR spokesperson in the Lower Colorado Region in Boulder City, Nev., said the quagga mussels were discovered in Lake Mead in 2007. Since then, the mussels have spread throughout the lake, estimated in the trillions, and have raised concerns with Hoover Dam's hydroelectric production, which is similar to Lahontan Dam.

Davis said officials have used several methods in an attempt to rid the lake, and specifically, water intakes to the hydroelectric plant but have been unsuccessful.

“It's definitely created some new challenges and costly challenges,” Davis said. “The mussels are sticking to trash racks, intakes and they are getting through the gates and into the piping system.”

She said the BOR, which operated the dam, has taken steps to clean out the mussels. One plan of attack was running water through a box with an ultra-violet light blasting the mussels. Davis said it had some effect.

Another has been using high-pressure sprays, but that only knocks the mussels out the infested areas and doesn't kill them. One other option was to use coating material to keep the mussels off the water gates.

“The only success they've had is with copper, but that's a heavy metal and not OK for water,” Davis said.

Davis said a new treatment is in the works at Davis Dam in Arizona four miles east of Laughlin, Nev. The treatment is called ZequanoxTM, which will be pumped into the cooling pipes of the dam. Davis said Zequanox uses dead bacteria to feed the mussels, which destroys their digestive system. The treatment was developed by Marrone Bio Innovations, Inc., in Davis, Calif.

The BOR will use initially use 200 milligrams per liter to kill the quaggas, then the amount will be lowered to 10 mg/L for maintenance to continue the eradication of larvae.

Davis said the BOR hasn't noticed any damage to fish and other lake wildlife, but Lake Havasu in Arizona has seen a rise in weeds. The quagga mussels have eaten much of the plankton, clearing the water allowing sunlight to beam through the surface.

“The mussels are eating the tiny, little organisms that block the sunlight to the weeds,” Davis said. “They're just growing out of control.”

Munoz said recreation has been affected. He added that marinas, docks, boats in addition to other structures, have sustained damage from the mussels.

However, Lake Mead, according to Munoz, is the only area with a prevention program. The program uses education about the quaggas including rangers on the water speaking about the mussels and signs throughout the park.

“We're talking hundreds of thousands of dollars in damage to structures around the lake,” Munoz said.

He added boaters who have been in the water for more than 20 days are the ones at risk of carrying larvae or grown mussels.

“Then you need to take the steps to steamwash your boats,” Munoz said.