As required by the U.S. Bureau of Reclamation to help prevent the spread of the highly invasive golden mussel (limnoperna fortunei), effective April 14, 2025, all trailered or motorized vessel owners wishing to launch at Folsom Lake or Lake Clementine will be subject to an inspection and a quarantine for Aquatic Invasive Species.
Golden mussels were recently discovered in the Port of Stockton in October 2024, the first known occurrence in North America. This highly invasive non-native species poses a significant immediate threat to the ecological health of the waters of the state, water intake and conveyance systems and water quality. Golden mussels can survive in a wider range of conditions than quagga or zebra mussels. Golden mussels can dramatically reduce the abundance of both zooplankton and phytoplankton, leading to widespread food web impacts, including to fisheries. Mussel invasions elsewhere have been associated with an increased frequency of potentially-toxic blooms of Microcystis. Their propensity to rapidly colonize any available hard surface jeopardizes built infrastructure in any infested water bodies. They can cause significant damage to boats by attaching to hulls and clogging engines, which will lead to increased costs for boat owners.
Rather than close Folsom Lake to recreation boating, Reclamation and State Parks are opting for a prevention program. This action is necessary as a golden mussel infestation at Folsom Lake could cause substantial damage not only to the ecosystem but could also impact the power generation and water delivery systems at Folsom Dam and Reservoir.
Caption: Golden mussels colonizing a water pipe at a hydroelectric plant in Brazin (Mountinho, 2021).
After May 14, 2025, there will be staff inspecting boats at all OPEN boat launch facilities at Folsom Lake and Lake Clementine.
As per standard operating procedure, in the event that parking areas meet maximum capacity all vehicles will be denied entry.
Boat Launch Cable Seal Protocol
Effective April 14, 2025, Folsom Lake SRA and Auburn SRA will be implementing new protocols for boat launching at Folsom Lake and Lake Clementine. All boats meeting the requirements for the inspection procedures will be quarantined and an inspection seal will be applied. Vessels in compliance will be verified on site and permitted to launch. Every time a seal is applied or removed, information regarding the waterbody, date, CF number and other pertinent data will be entered into the Watercraft Inspection Database (WID).
Trained State Parks staff will inspect each vessel for the presence of mussels and onboard water. Once a vessel passes inspection a red quarantine seal will be applied for 30 days during which the vessel will not be permitted to launch. The seal will include a cable through the bow eye of the vessel and around the frame of the trailer to insure it is not launched. The seals are tamper evident and serialized. Each seal application will be entered into a database to confirm the date, vessel/seal numbers and the location. The day of the inspection is day 1 of quaratine. Vessels that have finished the 30-day quarantine may launch on day 31 or there after. Authorized staff will remove the seal prior to launching.
Upon exit from the Lake, all vessels must have a green seal attached by authorized staff to be allowed to freely launch at Folsom Lake and Lake Clementine. Staff will ensure there is no debris on the vessel, no standing water in the vessel, and that the ballasts and live wells are emptied before applying the outbound green seal. If a seal is not applied for any reason, the vessel will need to undergo another 30-day quarantine or decontamination.
Quagga and Zebra (Dreissenid) mussels and the recently identified Golden mussel (Limnoperna fortunei) pose a serious threat to California's waters and fisheries. The spread of these freshwater mussels threatens recreational boating and fishing, aquatic ecosystems and fisheries, water delivery systems, hydroelectric facilities, agriculture and the environment in general. As a means to stop the spread of these harmful invasive mussels, California is asking boaters to clean, drain and dry their boats!
Boaters should be prepared for inspections throughout the state designed to help ensure California's waterbodies remain mussel-free. Properly cleaning and drying can help protect boats and help boaters avoid quarantines or being turned away from a water destination. In addition to being sure to clean, drain and dry watercraft, the Division of Boating and Waterways urges boaters to plan for possible launch restrictions and inspections by calling waterbodies before leaving home. Programs and requirements vary and can change rapidly.
Golden mussels have been discovered at Rough and Ready Island, just west of the Port of Stockton and further downstream at a location known as Turner Cut in October 2024. This is a rapidly developing situation, and reports continue to come in and are being followed up on. These mussels were likely introduced to California by a ship traveling from an international port. This discovery of golden mussels in the Delta is the first known occurrence in North America. Visit California Department of Fish and Wildlife’s webpage for more information and for a map of verified sightings.
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