- đź“Ś Golden mussels first detected in Arvin-Edison Water District storage in December 2025, causing over $11.2 million in expenditures in Kern County.
- đź“Ś Projected costs include $23.8 million over the next six months and an estimated $36.4 million annually for ongoing management.
- đź“Ś A 30-day copper-based treatment in March cost $3 million, with another $1.3 million treatment planned; officials report 100% control of all life stages is achievable.
- đź“Ś Kern County Farm Bureau and local agencies urge Governor Newsom to declare a state of emergency to unlock additional funding and resources.
- đź“Ś Experts warn the mussels threaten water delivery, agriculture, and infrastructure, calling them 'perhaps the worst aquatic invasive species of our time.'
Kern County remains under a local emergency as golden mussels clog water intakes and irrigation systems, costing agencies millions. First discovered in the Arvin-Edison Water Storage District in December 2025, the invasive species has rapidly colonized canals and pipelines, prompting urgent calls for a statewide declaration.
Costs and Response Efforts
Since detection, local water districts and agencies have reported more than $11.2 million in expenditures related to golden mussel response, according to the county. Additional costs are projected at $23.8 million over the next six months, with an estimated $36.4 million needed annually for ongoing management. The Arvin-Edison Water Storage District spent $3 million on a 30-day copper-based treatment in March, developed by Dr. West Bishop of SePRO Scientific, which successfully eliminated a significant amount of mussels. This treatment is one of California's first large-scale programs targeting golden mussels. A follow-up treatment is expected to cost another $1.3 million. Resource manager Sam Blue noted the district had to pull funds from general reserves, as the expense was not budgeted. Blue noted that the expense will now be part of the annual budget. Bishop said there have been no issues with water delivery after the treatment, but emphasized that ongoing monitoring and control will be necessary. 'Unfortunately, these things are here to stay. I don't think they're going anywhere anytime soon, so it's gonna be a likely constant influx of these organisms that are gonna need to be routinely controlled or consistently controlled,' Bishop said. Blue emphasized the stakes: “People don’t realize that this mussels situation can literally stop water and so we definitely don’t want to do that. We’re all trying to stay on top of it, but a state of emergency declared by the Governor would definitely help us in treating and fighting this battle.” Bishop described the golden mussels’ rapid colonization as “impressively terrible.” He added: 'But even in less than a year, there's all these different size classes, new reproduction occurring. The amount of organisms per unit area has just exploded, even in a short period of time.' Now, there is growing evidence that the mussels can be controlled. Bishop's team is using EPA-approved copper-based treatments injected into flowing water systems, targeting both established mussels and microscopic larvae before they can spread. 'It's proven in the field that we can achieve, with the right exposure, we can achieve 100% control of all life stages of the mussel, with these registered technologies,' Bishop said. 'Don't underestimate these... these could be perhaps the worst aquatic invasive species of our time. They threaten all uses of our critical fresh water supply; they threaten our way of life,' Bishop added. 'The ability to grow food, the ability to have water coming into the drinking water treatment plant consistently. It's huge,' he said.
Local California Context
Kern County, a major agricultural hub in the Central Valley, relies heavily on water from the California Aqueduct and local storage. The golden mussels attach to pumps, pipelines, and canals, threatening irrigation for crops and drinking water supplies. The Kern County Farm Bureau sent a letter to Governor Gavin Newsom requesting a state of emergency, which would unlock state and federal resources. Similar local emergencies have been declared in other California communities, but no statewide declaration has been made.
On July 1, the Kern County Farm Bureau submitted a letter to Governor Gavin Newsom, requesting that a State of Emergency be declared related to the spread of invasive golden mussels in California. The letter also called for immediate permitting and financial assistance to support prevention, monitoring, mitigation, eradication, and infrastructure protection efforts throughout California. The letter was signed by 19 agricultural associations and organizations, 14 agencies and districts, and two government and economic organizations. According to the letter, golden mussels pose a significant threat to California’s water delivery systems, agricultural economy, public infrastructure, and environmental resources. “Recent confirmations by state and federal agencies have established the presence of golden mussels within California’s water conveyance infrastructure, including facilities associated with the State Water Project and United States Bureau of Reclamation Central Valley Project,” the letter stated. “This is no longer a potential threat, but an active infestation affecting critical systems relied upon by communities, farms, businesses, and water agencies across the state.” On May 12, the Kern County Board of Supervisors declared a local state of emergency due to the presence and threat of invasive golden mussels. San Joaquin County and Sacramento County have also declared local states of emergency. According to KCFB’s letter, as of June 22, 2026, local water districts and agencies in Kern County reported over $6 million in expenditures to address the spread of the invasive species, including remediation efforts, monitoring, technical assistance, and response activities. “Additional Kern County response costs are projected to total approximately $23.8 million over the next six months and an estimated $36.4 million annually for ongoing management and infrastructure protection,” the letter stated. “As infestations spread throughout California’s interconnected water systems, similar costs are expected across the state.” According to the California Governor’s Office of Emergency Services, pursuant to California Government Code section 8625, the governor may declare a State of Emergency in an area affected by a natural or human-made disaster when requested to do so by the affected local agency or if the governor determines that the local authority is inadequate to cope with the emergency. If the incident is so severe that effective response is beyond the capabilities of the affected local government and the State or Indian tribal government, the governor may request federal assistance, including a presidential emergency or disaster declaration, according to CalOES. According to KCFB’s letter, much of California’s water conveyance infrastructure is owned, operated, or regulated by state and federal agencies, including facilities associated with the State Water Project and Central Valley Project. As such, the letter asserts that addressing golden mussel infestations requires statewide leadership and investment. According to the letter, a statewide emergency declaration would recognize the urgency of the threat to the state’s water infrastructure and facilitate coordination across state, federal, and local agencies. A statewide declaration would also expedite access to resources and support funding needed to protect water infrastructure and combat the spread of golden mussels. “In addition to a State of Emergency declaration, we respectfully request that the State identify, allocate, and expedite emergency funding to assist local agencies, water districts, agricultural stakeholders, and infrastructure operators in responding to this emerging threat,” the letter stated.
Background
Golden mussels (Limnoperna fortunei) are native to Southeast Asia and have invaded waterways in South America and now the United States. They reproduce rapidly, with multiple size classes observed within months of detection. Unlike quagga and zebra mussels, golden mussels can tolerate warmer waters and are particularly aggressive colonizers. The infestation in Kern County is the first confirmed in California, raising alarms about potential spread to the Sacramento-San Joaquin Delta and other critical water systems.
Conclusion
Kern County officials and water agencies continue to battle the golden mussel invasion with copper-based treatments, but long-term management remains costly. A state of emergency could expedite funding and coordination. Public cooperation, such as cleaning aquatic equipment and reporting sightings, is vital to slowing the spread. Bishop says the focus is shifting from simply reacting to the invasion to learning how to manage it. Without aggressive action, the mussels could disrupt water delivery across the state. Additionally, experts warn that mussel clusters can clog drainage pipes, increasing the risk of flooding during heavy rains.