Monumental Questions - What are Golden Mussels?

Kristie Ehrhardt • June 5, 2025


You may have heard of Golden Mussels on the news or maybe at your local marina. They are a highly invasive and opportunistic bivalve species that has only recently been documented in North America. Native to China, Thailand, Korea, Laos, Vietnam, Indonesia and Cambodia, Golden Mussels (Limnoperna fortunei) have been documented in Hong Kong, Japan, Taiwan, Argentina, Brazil, Bolivia, Paraguay, Uruguay, and the United States. In fact, as of October 2024, their occurrence in the Sacramento - San Joaquin Delta and O’Neill Forebay in Merced County were the first known discoveries in North America. Golden Mussels are extremely opportunistic and can colonize fresh and brackish waters in bays, creeks, canals, lakes, rivers and other wetland areas with temperatures ranging from 41-95 degrees Fahrenheit. Golden Mussels are tolerant of pollution and can establish and reproduce in waterbodies with much lower calcium than Quagga and Zebra Mussels, making many more waterbodies in the state vulnerable to infestation. The Golden Mussels have extremely high reproduction rates and can reproduce during their first year of growth; each adult mussel can produce tens of thousands of free-floating veligers (larva) that will mature in the water column while flowing downstream until they are ready to settle. Due to their broad environmental tolerance, high reproductive rate, and free-floating life stage that allows for rapid dispersal, this alien species has become a threat to native fisheries and ecosystems.

 

Golden Mussels range in color from light to dark golden to dark brown and can reach nearly two inches long and can live for two years. Adults form byssal threads, also known as mussel beards, which anchor them securely to natural and man-made substrates in varying depths of water. These threads are strong enough to withstand abrasive wave action and high flows. Golden mussels have been found attached to hard surfaces such as the submerged logs, rocks, hulls of boats, buoys, and other equipment as well as soft substrates and aquatic plants.

 

The most common way invasive mussels such as Golden Mussels are transported between bodies of water is by hitchhiking on watercraft and other equipment. Invasive species such as Golden Mussels, can be introduced into formally unoccupied areas through ballast water of ocean-going ships, adults can be relocated by being attached to watercraft being moved from one body to water to another or nearly microscopic veligers can be moved by being in contained water within watercraft or other equipment. In areas where waterways are interconnected, Golden Mussel adults and veligers can move with the flow of water or watercraft going from one body of water to another. It is also possible that they move upstream in the stomach of fish – being undigestible by native fish and eventually passing through the fish.

 

Golden Mussels are ultra-efficient filter feeders. When dense colonies of these organisms form, they consume substantial quantities of microscopic plants and animals that native fish, game fish and other aquatic species depend on to complete their life cycle and flourish. Additionally, Golden Mussels have been demonstrated to cause shifts in algal communities that favor species that produce Harmful Algae Blooms (HABs), resulting in more adverse impacts to the environment. The dense congregations of mussels not only restrains water movement by biofouling (obstructing) pipes, pumps, hydropower and irrigation facilities as well as damaging watercraft motors. Removal is continuous and costly to maintain operational function which results in economic impacts to the community.

 

Community impacts as a result of Golden Mussels infestations include constraints on recreational waterbody usage such as mandatory inspections, boat quarantine periods, lake closures, and increased fees. Economic impacts may be seen as higher charges for water and power utilities to account for increased costs due to increased preventative maintenance frequency, infrastructure protection upgrades such as filters and strainers and other prevention devices such as Ultra Violet lights and repairs to infrastructure and facilities due to biofouling of Golden Mussels.

 

To help curb the spread of Golden Mussels, the California State Parks Division of Boating and Waterways asks that you

 

  • 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.

 

So far Golden Mussels have not been documented in any bodies of water within the Berryessa Snow Mountain National Monument but just last Friday they were found on a boat attempting to launch in Lake Tahoe. Vessel quarantine periods and decontamination requirements vary throughout the state, so please contact the manager of the water body before you launch. If you observe Golden Mussels in California you are urged to immediately report your findings to the California Department of Fish and Wildlife Invasive Species Program, or by email to Invasives@wildlife.ca.gov, or by telephone to (866) 440-9530. Clear, close-up photographs with an item for scale are encouraged to be submitted with your report.


-Kristie Ehrhardt (kehrhardt@tuleyome.org)

Tuleyome Land Conservation Program Manager

RECENT ARTICLES

Policy Corner: Keep Yosemite Public - Stop the Private Developer Land Deal

By Shai Demus • September 10, 2026
 Yosemite National Park belongs to the people. It should not be carved up to benefit a private developer. The National Park Service is working on a new proposal to give up a quarter-mile strip of land inside Yosemite National Park in exchange for property elsewhere in California. What's the goal? To provide a private developer with a new road and direct access from his 83-acre planned real estate development abutting the park to one of Yosemite’s central roads. This proposal deserves the public’s attention. The property is owned by Kingsbarn Realty Capitol, whose CEO wants to build a road connecting the private property to Yosemite. Previous efforts to establish this private access were rejected, including in federal court. The National Park Service has repeatedly refused similar requests for more than two decades. Our National Parks should not be carved up for private profit. National Parks were established in this country to protect America’s most interesting and iconic places for everyone to access, not to provide special access or development opportunities for private interests. Your action is especially timely because the Park Service has acknowledged that no final decision has been made, meaning there is still an opportunity for public scrutiny and opposition. Any eventual land exchange should be subject to federal laws, environmental review, and public notification requirements. Tell the National Park Service: Keep Yosemite public We can’t allow a national park to be reshaped around the interests of a private developer. Yosemite is a national treasure. Its lands, wildlife, cultural resources, and landscapes belong to the American people, and they should remain protected for generations to come. We have seen this kind of proposal before, and the public and the courts rejected it. We must make sure it does not come back through the back door. Yosemite is worth protecting. Speak up and keep it public. TAKE ACTION: Tell Interior Secretary Burgum to Keep Yosemite Public! Here’s How: Call your elected officials. Here is a sample script: “Hi, my name is [NAME] and I'm a constituent from [CITY/ZIP]. I'm calling to urge [Representative/Senator NAME] to publicly oppose the National Park Service's proposed land exchange inside Yosemite National Park, which would give a billionaire private developer, Kingsbarn Realty Capital, new road access through park land. I'm also asking [him/her/them] to call on Interior Secretary Doug Burgum to reject any further privatization or sell-off of our public lands. Yosemite belongs to the public, not private developers. Thank you.” Send a letter or email. You can use this template: Dear [Representative/Senator NAME], I’m writing as your constituent to urge you to oppose the National Park Service’s proposed land exchange inside Yosemite National Park. This proposal would trade a strip of park land to provide Kingsbarn Realty Capital, a billionaire private developer, with new road access from an 83-acre private property to one of Yosemite’s central roads. This is not the first attempt to establish this private access – previous efforts were rejected, including in federal court, and the Park Service has denied similar requests for more than two decades. Our public lands exist to serve the public, not to create development opportunities for billionaires. I ask that you publicly oppose this proposal and call on Interior Secretary Doug Burgum to keep Yosemite, and all our national parks, fully public and protected for future generations. Thank you for representing our community on this issue. Sincerely, [NAME] [ADDRESS/ZIP] Not sure who represents you? Find your U.S. Representative and Senators here .

Donor Spotlight - Marita Cantwell

By Nate Lillge • September 10, 2026
I first learned of Tuleyome in 2015 when the Berryessa Snow Mountain National Monument was created and it was in the news. I thought then of what a marvelous and impressive, important effort this was by so many people, including Tuleyome. Importantly it was so inclusive, involving people of so many different backgrounds and interests, getting the buy-in from the community at large. Once I learned about Tuleyome (and the meaning of the name - deep home place) and some of its conservation efforts, I decided that I wanted to contribute, at least in a small way. I come from a farming and research background, and newly retired, wanted to be more involved in conservation efforts and Tuleyome was local and ideal! I think the aspect of Tuleyome’s work that most resonated with me is the focus on educational programs for young people and adults. As an older person, I know that experiences we have in childhood have life-long impacts. Let them be positive and enriching experiences and let them include conservation and the natural world! Young people have many demands on their time and attention and most have limited exposure to nature. Regardless of our career paths, an appreciation of nature is vital for the well-being of us all. As a docent helper this past spring I was touched by three students who said this was the first time they had been out in nature. In 2024 I had the opportunity to participate in the Certified California Naturalist Program (CalNat) and was inspired by the lead instructors Geoff Benn and Nate Lillge, and invited speakers. And, I love the new manual about the Berryessa Snow Mountain National Monument , especially the geology section. My donations can be used toward any need but I particularly want to support the educational efforts for young people. The National monument is a treasure in our backyards. Its creation and subsequent enlargement in 2024, reminded me of the adage “think globally, act locally”. The multi-pronged conservation efforts of Tuleyome and its commitment to a diverse regional community are such important and positive actions. I see Tuleyome as a small but powerful inspiring organization.

Monumental Occasions - National Public Lands Day

By Kristie Ehrhardt • September 10, 2026
Public Lands Day is a national one-day party to celebrate the largest volunteer effort to benefit the wellbeing of our public lands. Because it’s so fun though, lots of organizations celebrate all week long with events beginning on Monday, September 21st. There are lots of activities to participate in such as trail building and maintenance (something Tuleyome doesn’t save up for one designated day, with your help we do it all year long!), planting native trees and vegetation, repairing and restoring habitat and structures, endangered species monitoring, cleaning up trash and removing invasive plants and much much more. If you can’t participate in person, there are virtual talks and even hikes that you can join without having to change out of your pajamas. Last year alone there were over 55,000 volunteers at more than 900 events across the country getting dirty with their community to spiff up those public lands that are near and dear to our hearts. The theme for National Public Lands Day (NPLD) this year is “Caring for Our Shared America” and because it is America’s 250th birthday, we think the turnout will be even more Monumental (ahhh, snuck that one in!). National Public Lands Day began in 1994 and occurs annually on the third Saturday in September. The yearly event is organized by the National Environmental Education Foundation (NEEF) in partnership with the National Park Service and other agencies. NEEF is a non-partisan, non-profit organization sanctioned by Congress in 1990 through the National Environmental Education Act. NEEF focuses on improving and maintaining public access to the environment for enrichment in our daily lives. Public Lands include forests, national monuments, wildlife refuges, grasslands, marine sanctuaries, lakes and waterways, city, county and state parks and beyond - spaces managed by public agencies and non-profits that provide places for public recreation and connection to each other and the environment. While planned events focus on improving the environment and opportunities for education, recreation, and the betterment of physical and mental health, a beneficial side effect is the kinship that naturally develops between those coming together for a common purpose. Some interesting events in the Cosumnes River Preserve include invasive plant removal by canoe, maintenance on their fabulous boardwalk and a family-friendly guided nature walk. Visit NEEF's website to find other events throughout the nation. If you’re interested in planning your own National Public Lands Day event, NEEF can help you with that too. To volunteer in your own community, contact local conservation groups, regional, state and federal agencies. National Public Lands day provides an opportunity for all nature lovers from seasoned hikers with callouses and stories to go with them to those just breaking in their first pair of hiking boots, a chance to work side by side to show appreciation for our shared public lands. If you aren’t able to volunteer you can still help better our public lands by following and practicing the Leave No Trace principles while recreating: Plan ahead and prepare Travel and camp on durable surfaces Dispose of waste properly Leave what you find Minimize campfire impacts Respect wildlife Be considerate of others Practicing these ideas minimizes our impact on the environment, wildlife and others. These principles are as important in our local neighborhood parks as they are in our national parks and monuments. Join Tuleyome in celebrating Public Lands and an enduring commitment to conservation - not only on September 26 but everyday. Now, go take a hike!