In response to the recent detection of golden mussel (Limnoperna fortunei) in the Sacramento-San Joaquin Delta, the state of California has developed a comprehensive Golden Mussel Response Framework(opens in new tab) to address this urgent invasive species threat. The discovery in October 2024 marked the first known occurrence of golden mussel in North America. To combat this threat, the framework provides coordinated strategies by multiple California departments to prevent further introduction and spread of golden mussels, as well as to contain and suppress infestations to minimize their impact on the environment, water conveyance, recreation and agriculture.

In addition, the California Department of Fish and Wildlife (CDFW) is offering $1 million in grant funding to boating facility operators to enhance efforts against invasive mussels, particularly the threat of golden mussels. This funding supports projects that help prevent the introduction and spread of invasive mussels in lakes, reservoirs and waterways, ensuring the long-term health of state waters. The grant solicitation and application link can be found on CDFW’s website.

Native to East and Southeast Asia, golden mussels pose a significant threat to California’s natural ecosystems, water infrastructure, agriculture, and economy. The invasive species has already caused major disruptions in other parts of the world, including heavy biofouling of water intake systems, and negative impacts to habitat and wildlife.

“The discovery of golden mussels in California is a serious challenge that requires coordinated action and a long-term commitment,” said CDFW Director Charlton H. Bonham. “This response framework recommends critical steps that must be taken across state, regional and local levels to limit the spread and mitigate the impacts of this invasive species.”

“Taking coordinated action to address this invasive species will help safeguard critical water infrastructure like the State Water Project from the negative impacts golden mussels can pose to water delivery systems,” said John Yarbrough, DWR Deputy Director for the State Water Project. “Using this new framework and close collaboration with partner agencies, DWR will implement strategies to address this invasive species and minimize impacts by monitoring for the mussels in SWP waters and developing a mitigation plan.”

Reservoir managers across the state are adjusting their recreational plans for the upcoming boating season to address concerns for the golden mussel.

“Recreational boating is a significant contributor to California’s economy, and California State Parks’ Division of Boating and Waterways (DBW) is working diligently with allied industry and agency partners to provide outreach and educational information to boaters and waterbody managers on the importance of the Clean, Drain and Dry(opens in new tab) message to help protect the state’s waterways from invasive species,” said DBW Deputy Director Ramona Fernandez. “DBW recommends boaters contact the waterbody manager to learn of any updated requirements before they head out.”

DBW maintains a list of contacts at: https://dbw.parks.ca.gov/inspections(opens in new tab).

The response framework developed by the Golden Mussel Task Force is composed of key state and federal agencies, including CDFW, DWR, California State Parks, California Department of Food and Agriculture, and several other federal and local partners. It outlines a comprehensive strategy to respond to the invasive species, focusing on preventing further introduction, containing mussels within currently infested waters and reducing population within the invaded range where feasible.

Key recommendations in the response framework include:

1. Containment and Prevention Measures
   • Development of a map of Delta launch sites to prioritize management at high-use sites.
   • Investigation of pathways of spread, such as watercraft and overland movement, aquaculture trade, etc.
   • Increased inspection and decontamination capacity for watercraft, with expanded training for inspectors.
2. Education and Outreach
   • Launch of education campaigns to inform the public about the golden mussel threat and how they can help prevent its spread.
   • Posting of signage at waterbodies where golden mussels are present promoting the “Clean, Drain, Dry” practice following and ending every outing.
   • Collaboration with businesses that provide watercraft cleaning services to promote industry standards.
3. Incentives and Partnerships
   • Promotion of watercraft cleaning services within and around the Delta to assist in controlling the spread of the mussels.

The Golden Mussel Task Force will continue to collaborate to mitigate the impacts of this invasive species and protect the state’s water resources. The Golden Mussel Framework is a dynamic document, evolving with new information and adaptive management strategies.

For more information or to learn how you can help prevent the spread of golden mussel and report sightings visit: https://wildlife.ca.gov/Conservation/Invasives/Species/Golden-Mussel.

###

Media Contacts:
Krysten Kellum, CDFW Communications, (916) 825-7120
Maggie Macias, DWR Public Affairs Office, (916) 902-7405
Adeline Yee, California State Parks, Newsroom@parks.ca.gov

Overview

• The first North American detection of golden mussel (Limnoperna fortunei) was in October 2024. Although this mussel is similar in appearance and impacts to quagga and zebra mussels, it can establish in waters with wider temperature and salinity ranges.
• Environmental impacts include loss of native and game fish through competition for the same food sources and as a contributor to harmful, fish killing algal blooms.
• Recreational impacts of this mussel include waterbody closures, mandatory inspections, reduced numbers of fish and shellfish for consumption, increased launch and/or entry fees.
• Economic impacts range include costly repairs and maintenance (boats, water infrastructure, hydroelectric facilities), reduced water flow affecting food production, water delivery to homes, and flood control.
• For more information, review our Golden Mussel Fact Sheet (PDF)(opens in new tab).

You can prevent the spread of quagga, zebra, and golden mussels by using this checklist every time you take your boat out of a freshwater lake, river or stream:

• Inspect all watercraft and equipment.
• Clean any visible mud, plants, fish or animals from watercraft and equipment.
• Drain all water, including from lower outboard unit, ballast, live-well, buckets, and anything else that contains water.
• Dry everything for at least five days or with a towel before reuse.
• Dispose of debris and unwanted bait, worms, and fish parts in the trash.
• Report any mussels or suspect invasive species you find to the California Department of Fish and Wildlife hotline at (866) 440-9530 or email: Invasives@wildlife.ca.gov and to the local marina manager or harbormaster.

CLEANING GUIDE BOOK:

California’s Quagga/Zebra Mussel Task Force developed a boat cleaning guide book for use by recreational boaters. The information contains general guidelines for all boaters and a basic checklist for inspecting and cleaning boats and recreational equipment for quagga/zebra mussels and other aquatic invasive species. There are also additional inspection and cleaning checklists for specific types of boats and equipment.