October 2007

New Lake Powell Test Results Do Not Indicate Mussels

Visitors Reminded Prevention Program Remains In Place

PAGE, Ariz. — New test results of water samples collected from Lake Powell do not indicate the presence of microscopic quagga or zebra mussel larvae. The water samples were analyzed using a microscopic method by the Center for Lakes and Reservoirs at Portland State University and by National Park Service biologists at Glen Canyon National Recreation Area.

Previous water samples analyzed by a Bureau of Reclamation laboratory using the microscopic method indicated the presence of quagga or zebra mussel larvae. The Bureau of Reclamation laboratory confirmed the presence of these mussels using DNA fingerprint technology.

“Given the uncertainty of this situation, we do not know whether a reproducing population of quagga or zebra mussels has become established in Lake Powell,” said Kitty Roberts, superintendent of Glen Canyon National Recreation Area. 

 “It is critical that boaters remember that our quagga and zebra mussel-prevention program remains in effect.  All boats coming from areas infested with quagga or zebra mussels must be properly cleaned or decontaminated before they may launch on Lake Powell.”

Since initially detecting the presence of microscopic mussels in early August, the National Park Service has made a concerted effort to search for adult mussels.  Divers have inspected more than 500 boats at the Wahweap Marina as well as underwater cables and concrete blocks. 

Glen Canyon’s underwater remote operated vehicle has searched several deep-water sites below the Wahweap Marina.  So far, no mussels have been found.

To prevent quagga mussels or any other aquatic nuisance species from being spread, boaters should thoroughly wash their boats and trailers after they leave a lake.  Bilges, wet wells, motors, and any other part of the boat that could hold water must be completely drained. 

Any other gear that has come into contact with the water — such as waders or fishing equipment — should also be washed.  The boat and all gear should be allowed to thoroughly dry in the sun for at least five days before being used in another water body.

For more information, visit www.nps.gov/glca or call (928) 608-6208.