From AZGFD. Hopefully boaters and others will do their part and follow the precautions listed. Though I doubt it…

Invasive mussels found at CAP intakes on Lake Havasu
Officials fear the invasion could spread to the interior of Arizona

PHOENIX – Divers have found quagga mussels at the Central Arizona Project (CAP) intakes at Lake Havasu earlier this week and officials fear this invasive mollusk could spread into central Arizona lakes.

The CAP canal is one pathway for these mussels to spread into central Arizona, but these aquatic invaders could also hitchhike on boats coming from the Colorado River lakes that have already been infested.

“Quagga mussels could spread into Lake Pleasant, if they haven’t already. These prolific invaders pose a significant, multi-million-dollar threat to our lakes, rivers, streams and water systems,” says Larry Riley, the fisheries chief for the Arizona Game and Fish Department.

The CAP canal provides water to the interior of Arizona and stretches into the Phoenix and Tucson areas. Lake Pleasant on the northern edge of Phoenix is filled each year with Central Arizona Project water.

Efforts are underway to examine this long canal stretching across the state to determine if these mussels have established themselves.

Bob Barrett, a spokesperson for the Central Arizona Project, emphasized that quagga mussels do not pose a threat to the public health or to the water supply. “We’ll do whatever it takes to keep the water flowing. If they begin to build up, we’ll scrape them off.”

During the last two weeks since their discovery at Lake Mead on Jan. 6, quagga mussels have been confirmed at lakes Mohave and Havasu, including adjacent to the structure that pump water from Havasu to parts of southern California. The invasive mussels have also been found at a fish hatchery in Nevada that provides trout to Lake Mead and Lake Mohave. Fish deliveries from that hatchery have been suspended until new procedures are in place to avoid the spread of these mussels.

The Dreissena species of mussels, which includes two closely related mussels, the zebra and quagga, are less than an inch long, but are extremely prolific. A single one of these mollusks is capable of producing up to a million microscopic larvae in a year.

Quagga mussels can be found at much lower depths than zebra mussels, which is not good news for the deep reservoirs often found in the West. These rapidly-spreading invaders can clog pipelines; damage machinery, such as boat engines; harm fishery resources and befoul bodies of water with waste. In time, they can permanently alter a lake’s ecosystem.

The Arizona Game and Fish Department, National Park Service, California Department of Fish and Game and the Nevada Division of Wildlife are urging boaters and other water recreationists to take positive action to avoid spreading this aquatic invasive species. Boaters (including personal watercraft, canoe and kayak users), divers and anglers should take the following precautions:

Drain the water from your boat motor, livewell and bilge on land before leaving the lake.
Flush the motor and bilges with hot, soapy water or a 5-percent solution of household bleach.
Inspect your vessel and trailer, removing any visible mussels, but also feel for any rough or gritty spots on the hull. These may be young mussels that can be hard to see.
Wash the hull, equipment, bilge and any other exposed surface with hot, soapy water or use a 5-percent solution of household bleach.
Clean and wash your trailer, truck or any other equipment that comes in contact with lake water. Mussels can live in small pockets anywhere water collects.
Air-dry the boat and other equipment for at least five days before launching in any other waterway.
Remove any mud or vegetation from your boat or trailer – mussels can hide and hitchhike in this material.
Do not reuse bait once it has been in the water.
Clean sensitive gear (diving and fishing gear) with hot water (140 degrees F) or a soak in warm saltwater (1/2 cup of iodized salt per gallon of water) and air-dry before use elsewhere.
These small invasive mussels, which originally came from Eastern Europe, have been causing multimillion-dollar problems in the Great Lakes and the Mississippi River Basin. The Colorado River is 1,000 miles farther west than any previously known colonies of these mollusk invaders.

For additional information on this aquatic invader and others, visit the Arizona Game and Fish Department Web site at,,, and the U.S. Geological Survey Web site.