A quagga mussel found this month in Lake Mead's Boulder Basin is the size of a penny. They can grow to be more than 1 1/2 inches long. Photo by Isaac Brekken/Review-Journal

Discussions are under way in the Interior Department to launch a multi-state effort to contain or slow the spread of quagga mussels found at Lake Mead, described by one scientist Tuesday as "one of the worst invasive species in the entire world."

"This is particularly troublesome," aquatic scientist Jim LaBounty, an expert on Lake Mead's ecology, told a panel of local, state and federal water officials known as the Lake Mead Water Quality Forum.

Unlike its cousin, the zebra mussel, quagga mussels are more prolific, reproducing 12 months a year instead of nine, and they can adapt better to deep lake conditions and currents with some thriving at up to 400 feet deep.

"This particular one is one of the worst invasive species in the entire world," LaBounty told his colleagues at the water quality forum.

Besides clogging water pipelines and fouling marine equipment, colonies of non-native quagga mussels can siphon nutrients and plankton from lakes and rivers to the detriment of the food chain of fish and other aquatic species.

"It certainly changes the ecological dynamics of any body of water they're in," LaBounty said about the quagga.

Based on the devastation quagga and zebra mussels caused in the Great Lakes region where they were introduced more than a decade ago in the ballast water of ships from Eastern Europe and Ukraine, LaBounty said, wildlife and water officials in Nevada, California and Arizona have about a year to get ready for dense infestations.

Instead of investing in a program to treat the mussels with chemicals to kill the quagga, LaBounty said, "You might as well save your money and learn how to live with it."

Kent Turner, chief of resources for the National Park Service at the Lake Mead National Recreation Area, said quaggas were initially discovered Jan. 6 in Boulder Basin. Since then, they have been found in areas of Boulder Basin, including:

• At the Nevada Department of Wildlife trout hatchery.

• Two out of three water intakes at Saddle Island.

• In Callville Bay.

They also have been found in Katherine Landing at the south end of Lake Mohave, in Lake Havasu and in a nearby reservoir that holds water for an aqueduct that supplies Southern California.

"The response is broadening, and already we're having discussions in the Interior Department of a broader response on the interstate level," Turner said. "That's one of the things we're beginning to explore."

Jon Sjoberg, supervising biologist for the Nevada Department of Wildlife in Las Vegas, said his agency is setting up a statewide monitoring program to see whether invasive mussels have been distributed to other lakes and urban ponds where trout have been stocked and boats from Lake Mead have been launched.

Turner said, "It's difficult for the public to understand. If you've been on Lake Mead or Mohave, clean your boat, have it dry for five days before taking it to another body of water."

He said quagga and zebra mussels have natural predators in some types of diving ducks and certain gobies, small fish.

"But the fact they will eat a few is nothing like control," Turner said.