January 24, 2007

Officials have now added Lake Mohave to the growing list of lakes along the Colorado River that are confirmed to have a type of destructive, invasive mussel. The search continues to determine the extent of the problem.

The Dreissena species of mussels, which includes two closely related mussels, the zebra and quagga, can clog water intake pipes, negatively affect hydroelectric power operations, ruin boat engines, and impact water delivery systems.

These invasive freshwater mussels were first spotted Jan. 6 at the Las Vegas Boat Harbor at the southern end of Lake Mead. Last week, mussels were also found at Lake Havasu. This week, officials confirmed that mussels have been found at Katherine’s Landing in Lake Mohave. Efforts continue to determine whether these invaders have made their way into the Central Arizona Project canal, which feeds the interior of Arizona.

These small invasive mussels, which originally came from Eastern Europe, have been causing multimillion-dollar problems in the Great Lakes and the Mississippi River Basin. The Colorado River is 1,000 miles farther west than any previously known colonies of these mollusk invaders.

“These small mussels can reproduce and spread rapidly, and are often difficult to detect until they have become well established. A long list of agencies and organizations are cooperatively mobilizing to address this threat,” says Larry Riley, fisheries chief for the Arizona Game and Fish Department.

Officials stress that while various cooperators are investigating the extent of the threat and coming up with multiple ways to combat this invader, another critical element is getting the public involved.

“Everyone needs to take reasonable precautions not to move them as hitchhikers,” says Riley. “Guaranteed, we need the public – especially boaters and anglers – to help prevent the spread of this aquatic invader.”

These mussels can survive in a few inches of water in the bilge or livewell of a boat, can attach to boat trailers, or even cling to the hulls of boats and other flat surfaces. The juvenile form or larvae of this aquatic menace is microscopic and not visible to the eye.

Boaters (including personal watercraft, canoe and kayak users), divers and anglers should take the following precautions to help ensure their boats, vehicles, trailers and other equipment do not become the means of infecting other waters:

Remove any mud or vegetation from your boat or trailer – mussels can hide and hitchhike in this material.
Drain the water from your boat motor, livewell and bilge on land before leaving the immediate area of the lake.
Flush the motor and bilges with hot, soapy water or a 5-percent solution of household bleach.
Inspect your vessel and trailer, removing any visible mussels, but also feel for any rough or gritty spots on the hull. These may be young mussels that can be hard to see.
Wash the hull, equipment, bilge and any other exposed surface with hot, soapy water, or use a 5-percent solution of household bleach.
Clean and wash your trailer, truck or any other equipment that comes in contact with lake water. Mussels can live in small pockets anywhere water collects.
Air-dry the boat and other equipment for at least five days before launching in any other waterway.
Do not reuse bait once it has been in the water.
Clean sensitive gear (diving and fishing gear) with hot water (140 degrees F) or a soak in warm saltwater (1/2 cup of iodized salt per gallon of water) and air-dried before use elsewhere.
Riley stressed that these invasive mollusks are just one of the aquatic nuisance species to be concerned about.

“Boaters, anglers and other water recreationists should really take routine precautions to avoid transporting any nuisance species. A lot of them are out there, such as golden algae or giant salvinia,” he says. “A few precautions now will help us protect our waters for the future.”