Tuesday July 7, 2026
SF Gate —
This weekend, during the Fourth of July, the frontline to protect California’s vital waterways is on land. Inspectors across the state are keeping a vigilant watch on boats towed to dozens of lakes and reservoirs, including Lake Tahoe, looking for any indication they are carrying an unwanted and damaging visitor, the golden mussel.
Already this year, three counties in California — Kern, Sacramento and San Joaquin — declared a state of emergency over the arrival of the mussels.
But at the state’s largest reservoir, Lake Oroville, state officials won’t be checking boats at all.
The rollback of boat inspections at Lake Oroville happened in April, in the wake of the mounting threat posed by golden mussels, and it is a surprising decision by the California Department of Water Resources. DWR and the California Department of Fish and Wildlife have launched a statewide campaign to stop the harmful invaders, in part by mandating boat inspections at key waterways.
Native to Asia, the golden mussel first appeared in California in the San Joaquin Delta in October 2024 and measures less than 2 inches in size. In under two years, the mussels have spread over 500 miles, as far north as the West Sacramento Port and down to San Diego. It’s a prolific species that can produce thousands of offspring every time they spawn, leading to damage in both water infrastructure and local ecosystems. In response to the threat they pose, local governments and state agencies have been on a mission to stop them.