Golden mussels spread to West Sacramento port as Yolo County weighs emergency order

The Abridged version:

• Invasive golden mussels have been found in waterways near the Port of West Sacramento.
• The bivalves were first detected in the Sacramento-San Joaquin Delta in 2024 and have since spread throughout the state.
• West Sacramento is the farthest north the mussels have been found, leading Yolo County leaders to consider declaring a state of emergency.

---

To the casual observer, the waterway that enters the Port of West Sacramento looks no different than it ever has.

But beneath the placid surface, a new front in a slow-burning environmental emergency has opened.

The California Department of Fish and Wildlife announced last week that golden mussels were discovered in the Sacramento River Deep Water Ship Channel and Washington Lake in West Sacramento.

In addition to clogging up infrastructure, the fast-spreading, invasive species can outcompete native species and cause harmful algal blooms.

“It does impact our native fish and wildlife,” department spokesperson Krysten Kellum said.

The small, hardy bivalve native to Asia was first detected in California in 2024 and proliferated in central and southern parts of the state. Until now, it had not made it farther north than the Sacramento-San Joaquin Delta.

Preventing spread

Once golden mussels are established, they are extremely difficult to get rid of.

Kellum said that in other parts of the state, officials have tried to control the outbreak with things like hot water treatments and manually scraping docks. Even if those efforts work in the short term, they don’t permanently remove the mussels.

“They come back,” Kellum said.

So far, the only real option has been trying to slow down the pest’s spread by making boaters and recreators aware of the risk.

Kellum said golden mussels cannot swim, but they can survive by attaching themselves to boats, which transport them to new bodies of water. That is likely what happened at the Port of West Sacramento, which is connected to the Delta by a ship channel that moves barges loaded with rice and cement.

To avoid that, boaters should be prepared to clean, drain and dry their equipment between each use. In some places, including Lake Tahoe and Lake Berryessa, owners will need to have their boats inspected before being allowed to launch.

“It’s so important that we just not help these mussels move over land or move upriver,” Kellum said.

Local emergencies

Because of the potential that golden mussels clog up water infrastructure and affect wildlife, Sacramento County declared a local emergency last month, joining San Joaquin and Kern counties. In a news release announcing the move, officials said it would allow the county to work more closely with regional, state and federal partners to confront the threat.

Yolo County spokesperson Will Arnold said the county is considering that option and will be working with West Sacramento and the port to coordinate next steps.

“There’s a lot to be worked through,” he said.

In the meantime, the county is looking to the state Fish and Wildlife Department for expertise on the matter. Arnold said that although the problem is new for Yolo County, the state agency has been dealing with it for years.

California’s recently adopted budget includes $6 million of one-time funding and $1.5 million of ongoing funding to help address the problem. The money will be used to set up decontamination control sites in the Delta.

Daniel Hennessy joins Abridged from the California Local News Fellowship. He’s a reporter covering Yolo County.