<\/p>\n
Golden mussels are an invasive species native to Southeast Asia that have proliferated in California\u2019s waterways since their discovery in the state in 2024. Now, state officials are investing over $6 million to combat the species\u2019 infestation, given its threat to water infrastructure.<\/p>\n
Xavier Mascare\u00f1as<\/p>\n
California Department of Water Resources<\/p>\n
The discovery of golden mussels at Sacramento\u2019s deepwater port late last month, though worrying, was not unexpected by researchers tracking the invasive species\u2019 spread through the Sacramento-San Joaquin Delta. But the ongoing challenge for authorities, and for the state\u2019s aquatic recreationalists, is keeping the destructive bivalve contained to the Delta\u2019s waterways.<\/p>\n
Since authorities first discovered the species in the region in late 2024, they\u2019ve sought to make sure the mussels don\u2019t spread to lakes and rivers that aren\u2019t tied into the Delta, including famed recreation destinations like Lake Tahoe and Lake Berryessa.<\/p>\n
\u201cAt this point, golden mussels have only spread to waters hydrologically connected to the Delta, and that\u2019s good news,\u201d Krysten Kellum, a spokesperson for the California Department of Fish and Wildlife Bay Delta Region, told The Sacramento Bee in an interview Friday.<\/p>\n
The discovery at the Port of West Sacramento, first reported last month and confirmed by California DFW on June 27, marks the farthest north in California that the mussels have been documented to date.<\/p>\n
First discovered at the Port of Stockton in October 2024, authorities believe golden mussels reached California\u2019s waterways via international shipping. Mussels and other invasive species often spread globally via ship\u2019s ballast systems, through which water is sucked into the ship at one port and discharged, along with the species living inside it, at another location.<\/p>\n
![\"Bags](\"https:\/\/www.newsbeep.com\/us-ca\/wp-content\/uploads\/2026\/07\/SAC_3114_DRH_2507231_WestSacPort.JPG\" "\\"SAC_3114_DRH_2507231_WestSacPort.JPG\\"")
Bags of rice are lifted onto a ship in the Port of West Sacramento on Thursday, July 31, 2025. DANIEL HEUER dheuer@sacbee.com <\/p>\n
Sacramento\u2019s port is connected to Suisun Bay by a 40-mile deepwater channel. These days, ships primarily leave carrying rice and come in carrying cement, according to West Sacramento\u2019s website about the port.<\/a><\/p>\n However, authorities say they think the mussels discovered in the port in June came not from a ship but from a locally established population in the Delta, Kellum said.<\/p>\n The DFW maintains an online map<\/a> tracking confirmed mussel sightings. It shows the species spread south after infiltrating the California State Water Project<\/a>, the network of pipelines, canals and reservoirs that provides water to the Central Valley and Southern California and is connected hydrologically to the Delta. Last December they were discovered in a water pipeline in the Santa Ana Valley south of Riverside, which is part of the State Water Project.<\/p>\n Sightings have been most heavily concentrated in the Delta itself, however. Though it\u2019s not clear exactly how they travelled to Sacramento\u2019s port, the facility lies upstream from the Delta, and mussels only flow naturally downstream \u2014 which suggests humans, as usual, inadvertently lent the species a helping hand.<\/p>\n \u201cThese mussels, they don\u2019t have legs, they can\u2019t swim upstream, they can\u2019t go over land,\u201d Kellum said. \u201cEverybody can do their part to keep these mussels from spreading to California\u2019s lakes and rivers.\u201d<\/p>\n The department, and a wide range of other state and local agencies, as well as nonprofits and other environmental organizations, have sought to hammer a simple message home: clean, drain, dry.<\/p>\n DFW offers the following guidance<\/a> on what that catchphrase in fact means:<\/p>\n \u201cAnyone boating or recreating on waterways around the Sacramento area, and throughout the Delta, should take precautions to stop the spread of golden mussel further upstream and overland on watercraft and equipment used in mussel-infested waters. Golden mussels attach to almost any underwater surface, including but not limited to boats, ropes, buoys and aquatic plants that entangle on anchors and trailers.<\/p>\n \u201cClean, Drain, Dry \u2014 inspect your watercraft, kayak, life vests, paddles and anything that touched the water every time it is removed from a water body. Remove all debris, animals and plants, and dispose of them in the trash. Drain all water from ballasts, bilges and live wells. Lastly, allow everything to dry until moisture is no longer present.\u201d<\/p>\n California DFW assists with surveying and testing efforts, but the work to protect lakes and reservoirs lies with local jurisdictions, Kellum said. The Tahoe Regional Planning Agency, for example, maintains boat inspection stations where watercraft are inspected and tagged for being cleaned, drained and dried before they\u2019re allowed to hit that lake\u2019s famed crystalline waters.<\/p>\n Not every California water enthusiast is playing ball. As of June 25, Tahoe authorities had stopped six boaters who sought to evade inspections so far this summer, according to a news release from the Regional Planning Agency. Those boaters face steep fines. Separately, inspectors have stopped two boats with golden mussels aboard from putting into the lake.<\/p>\n Whether Lake Tahoe can hold off the small invaders is a matter of pitched local concern. This week, the director of a local environmental organization told a television station<\/a> they worried the state lacked a coherent strategy for keeping the mussels from spreading, including from making their way up into the Sierras via watercraft or other means of human-aided conveyance.<\/p>\n Lawmakers recently gave the mussel prevention effort a funding boost<\/a>, putting $7.5 million toward five new decontamination sites around the Delta where boats and equipment will be inspected.<\/p>\n Why worry about golden mussels?<\/p>\n Golden mussels degrade both human infrastructure and the natural marine environment they thrive in. They are a hardy species, that can live in both fresh and brackish water, and in temperatures ranging from 41 to 95 degrees \u2014 such versatility accounts in large part for their successful rapid spread, and for water managers\u2019 fear.<\/p>\n In the natural environment, they do their damage by outcompeting some of the lower species in the food chain. They are \u201chighly efficient filter feeders,\u201d Kellum wrote in an email, \u201cand they consume large quantities of aquatic microscopic plants and animals that native species and sport fish depend on for food.\u201d<\/p>\n In doing so, the golden mussels can outcompete crawfish, snails and other native species. That dents a food source that fish, otters and other wildlife higher up in the food chain depend upon. Researchers have also linked the mussels to toxic algal blooms.<\/p>\n In the built environment, like dams and ports, golden mussels take root in irrigation pipes and other water infrastructure, where they commence what scientists call bio-fouling.<\/p>\n \u201cBio-fouling literally just means growing on,\u201d Kellum said. Golden mussels grow quickly, and researchers have found them particularly frustrating to infrastructure because they can grow up from a larval stage on the side of pipes, piers and other structures or arrive fully grown, as the adult mussels can detach from one surface and float downstream before attaching to another.<\/p>\n How quickly bio-fouling occurs is difficult to measure, Kellum said, because much depends on the structure itself \u2014 the circumference of an irrigation pipe, for example, will determine how long it takes a mussel colony to impact the flow of water through it<\/p>\n A YouTube video posted<\/a> by the California Department of Water Resources shows the mussels collecting thickly on grates that strain trash out of waterways and coating every inch of an unidentified piece of equipment.<\/p>\n At the Port in Sacramento, large adult mussels were found on a water monitoring instrument, Kellum said in an email. They hadn\u2019t been there when the instrument was inspected a month prior.<\/p>\n Any sightings of the golden mussel should also be reported to the CDFW online at its Report an Invasive Species Sighting webpage<\/a>, via email Invasives@wildlife.ca.gov, or by calling 866-440-9530.<\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/us-ca\/wp-content\/uploads\/2026\/07\/img-26-06-25-AD64D.jpg\" "\\"img-26-06-25-AD64D.jpg\\"")
A Lake Tahoe watercraft inspector applies an inspection seal to a boat that has been inspected and decontaminated at Lake Tahoe. Authorities have intercepted six watercraft this summer that allegedly attempted to launch on the lake with tampered inspection seals as officials work to keep invasive golden mussels and other aquatic invasive species out of Lake Tahoe. Tahoe Regional Planning Agency <\/p>\n