Rangers keep a watch for pesky mollusks

Tuesday, June 15, 2004 | 9:39 a.m.

The Memorial Day weekend discovery of zebra mussels on the hull of a boat that was preparing to launch into Lake Mead underscored the need for National Park Service and Southern Nevada Water Authority personnel to constantly be on guard against the invasive mollusks, officials said.

Natives of the Caspian Sea of Asia, zebra mussels are invading water bodies in Canada as well as the Great Lakes. A single female zebra mussel can lay more than 1 million microscopic eggs in a single spawning season, biologists said.

The mollusks, about the size of an adult's finger, have caused millions of dollars in damage in the Great Lakes by clogging water-supply pipes and ruining boat engines. Zebra mussels apparently came to the United States in the ballast of an ocean-going vessel. The were first discovered stateside in Lake St. Clair near Detroit in 1988.

In the case at Lake Mead, a 54-foot houseboat from Kentucky was preparing to launch at Temple Bar, an area on the Arizona side of Lake Mead, when an alert ranger spotted the zebra mussels on the boat, Park Service spokeswoman Roxanne Dey said.

The Park Service and the Water Authority are continuously checking the waters at five marinas around the lake, including Temple Bar. Rangers have not found any of the mollusks in Lake Mead.

In addition, rangers inspect out-of-state boats and educate boaters about the threat from the zebra mussel, Dey said.

The Park Service has applied for a grant to pay for a portable wash station for boats attending fishing tournaments on Lake Mead. The wash station would use chemicals that kill the mollusks.

The Kentucky boat stopped at Temple Bar must spend 30 days in dry dock to ensure there is no risk of infesting the waters with mussels.