Zebra mussels discovered in Lake Mead

By Bill Hutcheson

On January 6th, 2007, the fears of many western fisheries biologists became reality when a Las Vegas Harbor marina employee discovered a lone zebra mussel attached to a breakwater mooring cable. The alert employee notified the National Park service. Wes Baldwin, a NPS Zebra mussel-monitoring program volunteer and his team discovered several colonies of established Zebra Mussels within sample traps that had previously been set. Samples were forwarded to the US Fish and Wildlife service, which confirmed on January 9th that the samples were indeed those of the Zebra mussel.

Bill Dickinson, Lake Mead National Recreation Area Superintendent, in a quote from a National Park Service press release stated, “We are very concerned about this discovery, and its potential impacts on Lake Mead.” “We are taking immediate action, in cooperation and consultation with other resource agencies, to assess the extent of the problem and to develop a management plan.” Initial explorations have discovered Zebra mussels in Las Vegas Harbor marina, Lake Mead marina and Boulder Basin.

Steve Martarano, spokesman for the California Department of Fish and Game stated, “We are on high alert.” “This is news that we did not want to hear as we have been able to keep the Zebra mussel out of California to this point. Since the news of this borke, we are working with the Department of Boating and Waterways and the Department of Boating Resources to make formulating a plan to deal with this a top priority. Our approach will likely be educational at the onset, but may even go as far as checkpoints if necessary.”

Zebra mussels are a non-native species that were inadvertently introduced into the United States sometime in the mid 1980’s. Likely brought to the Great Lakes region in the ballast hold of some foreign ship, the Zebra mussel quickly established itself and currently inhabits much of the Great Lakes waterways, St Lawrence Seaway, and the Mississippi river drainage. This small clam like bivalve ranges in size from _ to _ inches and is distinguished by the striped pattern on its shell. This mollusk is considered a “biofouler” as it attaches to hard surfaces such as boat hulls and outdrives, pumping station pipes, docks and pilings, and other rocky surfaces. A single female can produce a million eggs during spawning season leading to quick colonization.

Why the concern? With reservoirs such as Lake Mead and the remainder of the Colorado River chain predominately used as a water source for much of the west, the impact of the Zebra mussel on the numerous intake, outflow, and electrical generating systems across the west is enormous. Not only could Zebra mussels inundate the entire pipe fed western reservoir system, but the costs of clean up and containment could run into the billions and potentially limit boater access to many waters.

Presently, a myriad of agencies has convened to start work on containing the spread of the Zebra mussel in Lake Mead. The U.S. Fish and Wildlife Service, Nevada Department of Wildlife, U.S. Bureau of Reclamation, California Fish and Game, Arizona Game and Fish, Pacific States Marine Fisheries, and Southern Nevada Water Authority have all mobilized in an effort to get a handle on the spread of this mollusk.

As boaters and fishermen, it is imperative that we take conscientious efforts to limit the spread of Zebra mussels via transportation in our personal vessels. Boaters are encouraged to carefully inspect their rigs when leaving the lake. Make sure that your motor has been drained, your bilge plug has been removed, and all water has been drained from your livewells. Also check to make sure that no mud or vegetation from the lake is attached to your trailer. Clean and dry any part of your boat that is wet with a towel – including your dogs!

More information will come out in the following weeks as divers discover the extent of the invasion of the Zebra mussel at Lake Mead. For further information, log on to www.nps.gov and type “Lake Mead Zebra mussel into the search box.