Nonnative Species

Hey Boaters: Please CLEAN, DRAIN, and DRY your Boat Completely before entering Whiskeytown Lake.

 

Boat motor infested with golden mussel. California Department of Fish & Wildlife photo.

Golden Mussels: A New Threat to North State Reservoirs

In October 2024 the highly invasive golden mussel was documented near the Port of Stockton in the Sacramento-San Joaquin Delta. This is the first documented case of this exotic mollusk in North America and the introduction was likely a result of ballast water from shipping being discharged into the Delta. The golden mussel is native to Asia and, since being introduced, have spread throughout much of the Delta as well as south into the O’Neill Forebay, the San Luis Reservoir, and waters associated with the California Aqueduct. The potential impacts to water infrastructure, boats, beaches, and the aquatic ecosystem is severe as this organism can grow in dense colonies containing as many as 80,000 to 200,000 organisms per square meter. These dense colonies can clog water pipes, encrust beaches with sharp shells, plug water intakes on boats, impede power plant operation, and filter out large quantities of microscopic animals and plants that fish and other species depend on for food.

This threat is new but similar to the threat posed by quagga and zebra mussels in many areas of the nation. The primary difference between golden mussels and other aquatic invasive species (such as quagga/zebra mussels) is their ability to tolerate a wider range of ecological conditions, namely very low calcium levels as well as having the ability to tolerate brackish waters. This is an immediate threat locally as all indicators point to this species being able to readily colonize Whiskeytown and other north state reservoirs if introduced.

You can do your part to keep our reservoirs from being infested with these mussels by following the state’s “clean, drain and dry” practices whenever you move boats, kayaks, or fishing equipment between water bodies. All watercraft must be cleaned, drained, and completely dried prior to being launched at Whiskeytown Lake. You should also clean, drain and start to dry your vessel in the parking lot upon trailering your vessel. The primary way that these organisms are able to move between water bodies is through direct transfer of adult mussels or from the microscopic veligers that live within the water prior to settling and developing into adult mussels. Expect to see National Park Service and partner staff inspecting boats at our public launch ramps this summer. Please help us keep Whiskeytown’s waters free of this emerging threat.

For more information on this evolving threat, visit the California Department of Fish & Wildlife's Golden Mussel webpage: California’s Invaders: Golden Mussel.

For questions regarding Whiskeytown Lake golden mussels, email us at [e-mail].