Officials try to keep mussels out of lakes

Friday, June 14, 2002 | 10:13 a.m.

National Park Service officials have not found zebra mussels in either lakes Mead or Powell and said they are trying to keep the invasive pests east of the Rocky Mountains.

Zebra mussels, named for their alternating dark and light stripes, grow no larger than two inches and feed on plankton in the water. The mussels reproduce so fast, other plankton-eating organisms starve to death and they have no natural enemies.

The mussels gobble up algae, the normal food for fish, and can kill off sports fishing, members of the Lake Mead Water Quality Forum meeting in Las Vegas learned Thursday.

Park rangers at Lake Powell are launching their third year of inspections and voluntary free boat cleaning to any craft -- even kayaks -- that may harbor the microscopic mussels which grow into a D-shaped shell and cling to anything.

Park Service biologist Bill Burke said there is no formal program to inspect boaters at Lake Mead, but he expects to develop one in a year or two with the help from Lake Powell's monitors.

Biologist Mark Anderson from the park service at Powell said since 1988 the mussels have spread from the Great Lakes to eight major rivers east of the Mississippi.

Lake Powell has instituted a screening program for the past three years, he said.

"I suspect they could be in the upper region of Lake Mead," Anderson said, because zebra mussels can hold on to anything from a fisherman's boot to a boat propeller to riding in a boat's bilge water.

Last year 13 boats with the potential for carrying the mussels were identified at Lake Powell on the Arizona-Utah border. Nine went for a high-powered, hot water wash down. The other four did not take advantage of the free wash, Anderson said.

Once in a lake or river, the mussels attach the flat side of their shells to water intake pipes, sewage treatment facilities, docks, buoys, boats, even a submerged golf ball, Anderson said.

Why not eat them or grind them up for dog food? Because they are full of toxins from munching so much algae, Anderson said. A single female can produce 1 million eggs before she matures.

Since the mussels are transported by people moving from one body of water to another, education, information and inspection are the best defenses, Anderson said.