Lake’s Invasive Mussel ID’D As Quagga

By Keith Rogers

By KEITH ROGERS

REVIEW-JOURNAL

The type of invasive mussel that has infested part of Lake Mead is one that had not been found previously in the United States west of the Great Lakes or the Mississippi River, wildlife officials said Friday.

Word of positive identification of the quagga mussel, which is from the same genus of the species known as the zebra mussel, came as the Nevada Department of Wildlife confirmed that the infestation had spread to the state’s fish hatchery on Lake Mead.

“It essentially doesn’t change what we’re dealing with,” said NDOW Supervising Biologist Jon Sjoberg.

Although it is a different species than officials previously thought was found Saturday in Lake Mead’s Boulder Basin, Sjoberg said the quagga, or Dreissena bugensis, is a zebra-type mussel that looks virtually identical to what’s commonly known as the zebra mussel, or Dreissena polymorpha.

The quagga mussel is slightly bigger than the zebra mussel. Some in the wildlife community refer to the quagga as a zebra mussel on steroids.

“The good news is they’re not zebra mussels. The bad news is they are not zebra mussels,” Sjoberg said.

He said that like zebra mussels, quagga mussels were accidentally introduced to the Great Lakes region by ships from eastern Europe and the Ukraine.

Sjoberg received an e-mail Thursday afternoon stating that positive identification of quagga mussels had been made by a pair of experts, Robert McMahon and John Morse at the University of Texas at Arlington’s Center for Biological Macrofouling Research, and independently by Jeff Herod of the U.S. Fish and Wildlife Service.

“This considerably narrows the potential list of sources for where these mussels originated. Almost assuredly it was the Great Lakes,” said the e-mail, distributed by David K. Britton of the U.S. Fish and Wildlife Service in Arlington, Texas.

National Park Service spokeswoman Roxanne Dey said it’s possible both types of mussels could be in Lake Mead.

Quagga mussels pose the same threats as zebra mussels by rapidly colonizing the lake and adjacent waterways, clogging conduits, damaging boat engines, and costing the marine, water supply and power industries millions, if not billions, of dollars in prevention upgrades and maintenance.

The negative impacts on native species could be substantial as well, one biologist said.

The specter of their spread looms in California and Arizona, where officials are checking to see if they have reached Lake Mohave, downstream of Hoover Dam on the Colorado River system.

Sjoberg said an inspection was conducted Thursday at Nevada’s facility on Lake Mead for hatching and stocking trout. “They were found throughout the hatchery,” he said.

Trout plants from the hatchery have been suspended. Sjoberg said he hopes they can resume soon at Lake Mead and eventually at Lake Mohave after protocols for stocking fish, like those in affected areas along the Mississippi River, can be adopted.

John Scott, manager of Willow Beach National Fish Hatchery on the Arizona side of Lake Mohave, about 10 miles south of Hoover Dam, said an in-depth investigation into mussel infestation was under way there.

“At the present time we have not found anything,” he said.

The facility, operated by the U.S. Fish and Wildlife Service, raises rainbow trout for recreational fishing. It also breeds endangered razorback suckers and bonytail chubs and is assisting in the recovery of the Devil’s Hole pupfish and the relict leopard frog.

On Lake Mead, the discovery of mussels at the state fish hatchery raised concerns that the infestation has the potential to spread beyond the lake to the Black Mountain Industrial Center, formerly Basic Management Inc., and even to Lake Las Vegas near Henderson.

Mark Paris, president and chief executive officer of Basic Water Co., said the company’s pipeline draws water from an intake structure at Lake Mead’s Saddle Island that has been in operation for about 50 years.

“The water is pumped from that intake structure, and the fish hatchery is close to our facility on Lake Mead. So it goes to the fish hatchery before it goes to our terminal reservoir near the city of Henderson’s water treatment plant,” Paris said late Friday.

Some of that water is treated and delivered in Henderson, “and some goes as raw lake water in our BMI plant,” Paris said.

Water from the same system is pumped into Lake Las Vegas at various amounts during the year, he said.

He said company officials don’t know if the mussels have reached the intake. The company’s intake is at a shallower depth than the two operated by the Southern Nevada Water Authority, about 130 feet below the surface at Saddle Island.

“We are going to send divers to the bottom of our intake structure and see if there are any of them down there to make sure they don’t clog up our intake structure,” Paris said.

The Southern Nevada Water Authority is taking similar precautionary measures, officials have said.

The newest of the water agency’s two intakes is equipped with a chemical feed system that was installed to inject potassium permanganate to kill invasive mussels should they be found there.

According to a U.S. Geological Survey Web site, there have been a few occurrences of quagga mussels outside the Great Lakes in New York, Ohio, Michigan and Pennsylvania. Some were sighted in the Mississippi River between St. Louis and Alton, Ill., in 1995.

(c) 2007 Las Vegas Review – Journal. Provided by ProQuest Information and Learning. All rights Reserved.