Invasion: Multiplying mussels threaten waters

A zebra mussel is no larger than the tip of a man's finger. It's hard to imagine anything so small could be a threat to something as large as Lake Powell — but it is.

A single mussel can produce upward of a million young a year. A year later, that one zebra mussel could be responsible for a trillion descendents.

At this point, authorities believe there are no zebra mussels in Lake Powell, but the threat of an invasion by the tiny crustaceans heightened in January when they were found downstream in Lake Mead.

The discovery also threatens other Utah waters, mainly Quail Creek and Sand Hollow reservoirs near St. George.

Steps are being taken to try to prevent the transfer of the mussels. Consensus is, however, that someday the transfer will happen.

Boat owners headed for any of the three waters — Lake Powell, Quail Creek and Sand Hollow — are being asked a series of questions at check-in fee stations.

If a boat has been used on any water along the Colorado River corridor downstream from Lake Powell, or on waters in the Mississippi drainage or the Great Lakes within 30 days, the boat will be checked and the owners asked to comply with a cleaning procedure.

They can:

• Wash down the boat and allow it to sit for five days prior to a scheduled arrival.

• Take the boat to a nearby cleaning station where it can be washed down with scalding-hot water.

Cleaning stations have been set up at Wahweap, Bullfrog and Halls Crossing marinas on Lake Powell, and plans are in the works to set up stations near Quail Creek and Sand Hollow.

Since the discovery in January, officials have now found the mussels in a number of waters below Mead, including Havasu, Mohave and inlet pipes to both California and Arizona.

At first it was believed the tiny crustacean found in Mead were the common zebra mussels. It was later discovered they were a subspecies of the zebra, called quagga mussels.

The mussels originally came from Europe with large oceangoing vessels headed for the Great Lakes region. They were first detected in the Great Lakes 18 years ago. The quagga were discovered within the past 10 years. The quagga are more of a threat because they can live at greater depths, can attach to a wider range of substrate and are more prolific. The quagga is often described as a zebra on steroids.