January 21, 2007

The invasive Quagga mussel has been positively identified in California, the Department of Fish and Game said today. Quagga mussels were discovered by Metropolitan Water District divers Wednesday, Jan. 17 at Lake Havasu, and again today about 14 miles to the north. A multi-agency effort will continue to monitor California waters to determine the extent of the infestation. The State also will focus its efforts on seeking the public’s help in attempting to prevent the spread of the invasive, ecosystem-killing species, which were initially found earlier this month in several locations at Nevada’s Lake Mead.

“Today’s confirmation was not good news but we are already casting as wide a net as possible to stop the spread of Quagga mussels into California waterways,” said Department of Fish and Game (DFG) Director Ryan Broddrick. “Having all boaters aware of this problem and willing to help us help them is critical.”

Beginning Monday, a public toll-free number will be available Monday through Friday, 8 a.m. to 7 p.m., at 1-866-440-9530. DFG urges all boaters and anyone connected to marine environments to take the following steps that will inhibit the spread of the mussels:

• Thoroughly wash the hull of each watercraft once it leaves the water;
• Drain any water through the vessel’s plug, and ensure the area is dry;
• Ensure the vessel’s lower outboard unit is drained and dry;
• Clean and dry any live-well aboard the vessel;
• Any vessel traveling from Lake Mead should remain dry and out of water for five days.

The task force has added dive teams to search Lake Havasu and the Colorado River for further evidence of the mussels. Diving will continue near the recent discoveries to provide a better understanding of the extent of the infestation in Lake Havasu and the Colorado River System waters, said Susan Ellis said, DFG’s Invasive Species Coordinator.

Wednesday morning, divers from the Metropolitan Water District discovered the mussels attached to concrete surfaces and anchors during an inspection at Whitsett Intake in Riverside County’s Lake Havasu. They were found in small numbers in 30 to 50 feet of water and ranged in size from a quarter-inch to an-inch-and-quarter. On Friday, DFG divers found a single quagga mussel about 30-feet deep on a steep sandstone wall near Grass Island, across the river from Lake Havasu City, and about 14 miles north of the other California discoveries.

“This joint effort, already underway by state and federal agencies, indicates the critical importance of preventing the expansion of this invasive species,” Ellis said. “Left unchecked, Quagga mussels have the power to alter the ecology of California water bodies and impose a heavy maintenance burden on water suppliers.”

Other efforts will focus on inspections of marina and shore areas, and adding watercraft checkpoints along the main freeways into southern California. Authorities discovered quagga mussels living in the Colorado River at Lake Mead along the Arizona-Nevada border on Jan. 6. Quagga mussels are a harmful invasive species that disrupts traditional aquatic ecosystems. The tiny freshwater bivalve mollusk, similar to zebra mussels, have severely affected water infrastructure in the Great Lakes.

Establishment of Quagga mussels in California, specifically in areas like the Sacramento-San Joaquin river systems and the Delta, could exacerbate the problems faced by native species such as Chinook salmon and Delta smelt by removing food at the base of the fish food web upon which these native fish depend. California, authorities are concerned that they will further spread to the lower Colorado River, where California water agencies including Imperial Irrigation District and Metropolitan Water District of Southern California have intakes. The mussels can spread when they attach to boats that owners move by trailer to other water bodies.

Divers from DFG will work below the surface of Lake Havasu to determine other areas where quagga mussels might be present. The scuba effort is expected to take several weeks and will extend throughout the lower Colorado River.

Another key element in the prevention plan establishes inspection teams at agricultural checkpoints to help examine watercraft that may carry the mussels. DFG wardens and staff from the California Department of Food and Agriculture (CDFA) will check vehicles towing a watercraft at the Yermo check station, on Highway 15 east of Barstow in San Bernardino County; at Highway 40 at Needles, and at Vidal Junction, west of Parker, AZ. State agencies may seek legislation for additional inspection authority, Ellis said.

Task force members will inspect marina and shorelines along Lake Havasu including boat hulls, docks, watercraft launching areas and the anchor lines attached to water buoys. Water will be sampled for the presence of larval mussels. Team members will develop a long-term monitoring system for the lake.

The multi-agency effort includes DFG, CDFA, the state departments of Water Resources, Parks and Recreation, Boating and Waterways, Bay Delta, as well as the Energy and State Lands commissions. Also involved are the U.S. Fish and Wildlife Service, National Parks Service, Nevada Department of Wildlife, Arizona Game and Fish, and the Metropolitan Water District. The coordinated command structure allows effective use of both state and federal resources.

Quagga mussels are in the genus Dreissena, which also includes the better-known zebra mussels, and were first discovered in the United States in the Great Lakes in 1989 just one year after the discovery of zebra mussels. Since the 1980s, dreissenid mussels have spread, unchecked by natural predators, throughout much of the eastern United States. They currently infest much of the Great Lakes basin, the St. Lawrence Seaway, and much of the Mississippi River drainage system. They have begun to spread up the Missouri and Arkansas rivers.

Quagga mussels negatively affect the environment by reproducing quickly and in large numbers. These mussels attach to submerged surfaces such as piers, pilings, water intakes, and fish screens. They cause significant maintenance challenges for raw-water systems, requiring millions of dollars annually to treat.