Lake Oroville boaters got checked for invasive golden mussels over Memorial Day weekend. The checks are mandatory and will now be a permanent fixture at the lake.
The inspection site is located at the North Thermalito Forebay. There, officials examine all water vessels planning to use the lake, from jet skis to pontoons to fishing boats.
"We ask that before you get here, make sure your boat is 100% dry. It's really important."- Eric See, California Department of Water Resources environmental program manager
Golden mussels entered the U.S. for the first time in October 2024. If they got into Lake Oroville water officials say the result could be damaging to the state’s water system.
Lake Oroville is one of California’s most important reservoirs. If the invasive mussels invaded it, they could clog vital pipes and pumps that deliver water to millions of people and hundreds of thousands of acres of farmland.
The reservoir also feeds water into the Feather River Fish Hatchery, which raises millions of chinook and steelhead salmon for the state.
“We're very concerned, because it's very vulnerable to something like this. There's a lot of small diameter plumbing in the hatchery. And the fish and the eggs in the hatchery can't be dewatered for any amount of time, and within just a few minutes you can lose millions of fish,” said Eric See, an environmental program manager for the state’s Department of Water Resources (DWR).
This is why DWR started the mandatory boat inspections.
Microscopic larvae make dry boats, decontamination essential
Before getting checked, boaters need to clean, drain and dry their vessel.
“We ask that before you get here, make sure your boat is 100% dry. It's really important,” See said.
Golden mussels produce microscopic larvae that can travel through water. If a boat is wet, it can carry that larva to a new waterway.
Boats with features like ballast tanks have to be decontaminated with hot water at the inspection site to kill any possible larvae, even if no mussels are found. Owners can opt out of decontamination, but will have to quarantine their boat for 30 days before launching. Once the boat is decontaminated, it will receive clearance to enter the lake.
To pass an inspection, boats must not have any visible signs of mussels and must be completely dry. Once they’re cleared, they receive a blue seal that clips onto the vessel.
This gives them approval to launch at one of the lake’s boat ramps.
“We're concerned about any invasive mussel that can come in ... we don't know what the next mussel might be."- Eric See, California Department of Water Resources environmental program manager
“When they come off the lake at the end of the day, they will be offered the opportunity to get sealed right there at the boat ramp. And that way, the next time they come back to Lake Oroville, as long as that seal is intact, they don't have to come back here to the inspection station,” See said.
If inspectors find a boat with mussels, it will be tagged with a red quarantine seal and reported directly to the California Department of Fish and Wildlife (CDFW). CDFW must approve the boat before it can launch again.
Today it’s golden mussels, tomorrow it could be something else
These inspections aren’t temporary. See said right now they’re targeting golden mussels, but that might not always be the case.
“We're concerned about any invasive mussel that can come in. So we didn't even know, at least, personally, I didn't know the gold[en] mussels existed before last October, when they showed up in the Delta. So we don't know what the next mussel might be,” See said.
This is the first time a mussel inspection has been required at Lake Oroville. The lake has low calcium levels, and previously invasive species found in California could not survive in the waterway. However, golden mussels can survive in the lake’s water, making the inspections vital.
As of Monday, more than 1,700 inspections were completed. Golden mussels were found on one of those boats, and it’s not allowed in the lake until CDFW clears it.
