Although there have not yet been detections of the golden mussel in the waterways of Sutter, Colusa and Yuba counties, the California Department of Fish and Wildlife is asking that everyone be on guard. That’s partly because these freshwater mollusks were sighted in Sacramento County in 2024 and 2025 – directly in the Sacramento River and parts of the Delta – and last week elected supervisors in those jurisdictions declared a local state of emergency. The invasive species from China can disrupt native aquatic ecosystems and get into plumbing or essential water passageways. … “You can see the mussels are in the Delta, and downstream of the Delta, but they have not been detected in lakes upstream, in the foothills,” [CDFW information officer Krysten] Kellum said.