SMUD tightens boat rules at Rancho Seco to block invasive mussels ahead of derby

The Sacramento Municipal Utility District announced new boating restrictions Tuesday at Rancho Seco Lake near Herald in an effort to prevent the spread of invasive golden mussels, which were recently discovered in the Sacramento-San Joaquin River Delta.

The changes follow a California Department of Fish and Wildlife alert warning of environmental and economic harm from the mussels, which are native to Asia and pose a threat to native species, water infrastructure and water quality.

Effective immediately, only hand-launched watercraft — including kayaks, canoes, paddle boats, and other small vessels — are allowed on the lake, according to SMUD, which operates the man-made reservoir near its former nuclear power site. All boats must be clean, drained and dry, and cannot have been in any other body of water within the past 30 days. Live aquatic bait is prohibited, and inspections by certified personnel or trained dogs will be required before entry.

What are the restrictions?

The restrictions imposed, according to the utility:

• No trailer-launched watercraft will be allowed on the lake.

• Small electric trolling motors allowed, as are canoes, rafts, kayaks, rowboats, paddle boats, inflatables, sculls and other hand-launched recreational watercraft.

• Hand-launched watercraft are allowed only if they have not been used in other waters, including the Delta, for the past 30 days.

• No aquatic bait and lures are allowed — no baitfish, crawfish, crabs. Non-aquatic bait is permitted.

• All watercraft will be required to undergo an inspection.

• All boats must be clean, drained and dry before launching.

Golden mussels were first detected in the Port of Stockton in October and spread to O’Neill Forebay in Merced County. The Oct. 17 discovery was the first in North America, according to state wildlife officials. The mussels easily make their way into live wells, bilges and ballast tanks, watercraft’s engine systems, plumbing and other compartments onboard boats. The mussels can survive for extended periods of time in the water that collects in the craft’s systems.

Since the Stockton discovery, local agencies including Solano County have imposed travel restrictions and quarantines on watercraft sailing from the Delta.

In November, Solano County barred watercraft traveling from the Delta from launching in Lake Berryessa without a 30-day quarantine or decontamination.

SMUD emphasized that the restrictions are designed to protect the lake’s ecosystem and preserve recreational access. The 400-acre Rancho Seco Recreational Area remains open for fishing, hiking, camping and other activities. The annual Trout Derby on April 5-6 will proceed as scheduled, SMUD said, with inspection teams onsite to ensure compliance with the new rules.

This story was originally published March 27, 2025 at 7:00 AM.