Napa County moves to authorize inspections of watercraft at Lake Berryessa to prevent invasive mussels

The Napa County Board of Supervisors signaled its intent Tuesday to adopt an ordinance that would authorize inspections of watercraft at Lake Berryessa aimed at preventing the spread of invasive golden mussels.

County counsel and staff told the board the draft ordinance would add chapter 6.02 to the Napa County Code and would give on‑site inspectors and law enforcement explicit authority to stop and inspect boats, trailers and other equipment at Lake Berryessa. The change codifies an inspection and tagging program already run on the reservoir and adds enforcement tools and penalties, including misdemeanor charges for knowingly trying to avoid inspection.

The move follows a presentation from Martin Peralez, a PhD aquatic ecologist with the Napa Resource Conservation District, explaining the threat posed by the golden mussel (a small, fast‑reproducing freshwater mussel native to Asia). Peralez described how the organism’s microscopic larval stage (veligers) and attached adult…