Does Lake Berryessa have mussels?
Lake Berryessa is mussel free! The Asian Clam, which can be found in Lake Berryessa, is commonly mistaken as a zebra, quagga or golden mussel but they do not pose the same threat.

How do you know Lake Berryessa does not have zebra, quagga or golden mussels?
Solano County Water Agency regularly samples the waters of Lake Berryessa and the Solano Project for the presence of larval and adult zebra, quagga or golden mussels as part of our early detection monitoring program. There are biologists on staff who are trained in the microscopic evaluation of plankton samples for the detection of larval mussels in our water supply. CDFW and USBR also conduct tests to ensure Lake Berryessa is negative for zebra, quagga or golden mussels.

Why do I have to install a seal on my watercraft?
The best way to keep Lake Berryessa mussel free is to ensure each boat entering the water does not pose a risk of harboring mussels. This is done through applying a custody seal connecting the boat to the trailer. The seals can be applied by Lake Berryessa staff including SCWA Watercraft Inspectors, USBR Rangers, Concessionaire employees as well as other businesses listed on our wesbite. The red seals indicate the watrcraft is underging the mandatory quarantine prior to launching at Lake Berryessa. After 30 days, these watercraft are free to launch and can have a green seal applied at the launch ramp when they leave the lake. The green watercraft seals are intended to identify boats who last launched at Lake Berryessa that are mussel free, eliminating the need for future quarantine.

Why do I need a RED 30-day quarantine seal?

Due to the presence of golden mussels in the Delta and the thousands of boats that travel from the Delta to Lake Berryessa every year, RED seals are required for any vessel wishing to enter Lake Berryessa, regardless of the watercraft history.

After 30 days, the watercraft quarantine period will be lifted, and the watercraft will be allowed to launch into Lake Berryessa. When the watercraft leaves the lake, please stop at the boat launch office and a GREEN seal will be applied to the watercraft.

Where can I get a RED seal?

RED seals can be placed on your vessel at the following locations:

Solano County Water Agency Parking Lot: 810 Vaca Valley Parkway, Suite 202, Vacaville, CA, 95688, Monday-Friday 9am-3pm, Sat 7am-12pm

All boat launches around Lake Berryessa (time varies depending on Concessionaires)

Sweeney’s Sports: 835 Lincoln Avenue, Napa, CA, 95688, Monday-Saturday 10am-5pm

Gone Fishin’ Marine: 1880 N Lincoln St, Dixon, Ca, 95620, Tuesday-Friday -am-5pm, Saturday 9am-4pm.

Will my RED or GREEN seal be accepted at other lakes besides Lake Berryessa?

Although Solano County Water Agency is working in tandem with other agencies and lake managers to streamline this process, we recommend calling ahead to see if the lake you are visiting will accept the RED 30-day quarantine seal or GREEN seal issued for Lake Berryessa.

If I get a RED seal placed on my vessel from a different lake, will it be accepted at Lake Berryessa?

If your watercraft has received a RED seal from another lake and is currently under a 30-day quarantine, it will not be allowed to launch at Berryessa. However, if a RED seal is applied at another lake and the 30-day quarantine is over, the Watercraft will be allowed to launch as long as one of the following criteria are met:

• The watercraft information has been added to the Watercraft Inspection and Decontamination (WID) database. Many lakes applying seals use this system.
• A paper receipt is available to prove the date and location of the application of the seal.

How do I get a GREEN seal after my 30-day quarantine?

When you have concluded your 30-day quarantine, you may launch at a site in Lake Berryessa with a RED seal still attached to your boat. A concessionaire or Solano County Water Agency staff member will be able to remove that seal and the watercraft will be allowed to launch and replaced with GREEN seal on your watercraft upon departure from Lake Berryessa.

Please note that to receive the GREEN seal, your boat must depart the lake during regular concessionaire hours.

Do I need to replace my RED seal with a GREEN seal before going to Lake Berryessa after the 30-day quarantine?

No, after the 30-day quarantine period is over the watercraft is free to launch at Lake Berryessa with the RED seal attached. Upon departure from the lake, you can have a GREEN seal applied by the concessionaire staff.

What happens if I depart Lake Berryessa after normal concessionaire hours?

In order to receive a GREEN seal upon departure from the lake, it must be during the normal business hours of the launch ramp facility. Unfortunately, if the facility is closed when the watercraft is leaving the lake, the watercraft will not be able to receive a GREEN seal and the 30-day quarantine process will start over, or a decontamination will be required to bypass the 30-day quarantine.

How long is the decontamination process?

The decontamination process can take 30 minutes to an hour depending upon the size and type of the vessel.  

What can I expect during a vessel docontamination? 

Click on the videos below to learn more about what to expect during a vessel decontamination.

• Inboard Engine Decontamination
• Ballast Bag Decontamination
• Inboard/Outboard Engine Decontamination

Physiology & Ecology of Golden Mussels 

Physical Description: Golden Mussels are sessile (non-moving) bivalves (two-shelled mollusks) whose color varies from a light golden to darker yellowish-brown and brown hues. Adult shells are typically 2-3 cm in diameter, with some reaching sizes of >4 cm. Golden Mussels typically grow in dense, reeflike colonies containing as many as 200,000 organisms per square meter.

Habitat: Originating from China and southeast Asia, Golden Mussels now inhabit shallow (< 10 m), freshwater aquatic environments worldwide. They tolerate many environmental stressors including wide ranges of temperature, pollution, and low oxygen. Preferring fresh water, Golden Mussels can nevertheless tolerate salinity of up to 10 ppt for as much as 30 days (Sylvester et al., 2013).

Life History: Mussel larvae develop into mobile veligers that propagate through a water body before reaching the settling (plantigrade) phase roughly 11-20 days after spawning. They then colonize hard surfaces and grow into adult mussels. Once attached, they remain sessile indefinitely.

Ecosystem Impacts: Golden Mussels are highly-effective ecosystem engineers, with the potential to catalyze broad-scale environmental change equivalent to invasions by Zebra or Quagga Mussels. They can dramatically reduce the abundance of both zooplankton and phytoplankton, leading to widespread food web impacts. Mussel invasions elsewhere have been associated with an increased frequency of potentially-toxic blooms of Microcystis. Their propensity to rapidly colonize any available hard surface jeopardizes built infrastructure in any infested water bodies.

Monitoring Notes: Golden Mussel colonies typically attach to solid substrates, preferring piers, moorings, rocks, downed trees, or other submerged objects. The do not grow in soft, unconsolidated sediments and are therefore unlikely to be detected using typical methods for monitoring the benthos (e.g., grabs and cores).

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Quagga & Zebra Mussels

Quagga Mussels (Dreissena rostriformis bugensis) are a small freshwater mollusk.  They are an invasive species native to Russia and Ukraine and are thought to have been transported to the Great Lakes region in the ballast water of transoceanic ships. They have some diagnostic features to identify them from zebra mussels.  The quagga’s shell has a rounded angle, a convex ventral, and their color varies from black, white, cream, but they are generally paler (U.S.G.S.). The quagga causes problems because they are “water filterers” and are able to remove large amounts of phytoplankton and suspended particulates from lakes and streams (Sea Grant Michigan). This can have a potential to alter the balance of the aquatic food web.  The mussels’ tissues also trap contaminants, which can be exposed to wildlife if they are eaten.  Like zebra mussels, the quagga also clogs water structures that can reduce pumping capabilities for water treatment (Sea Grant Michigan).

Zebra mussels, a native species of Eastern Europe, were first introduced in the United States through ballast water released into the Great Lakes in the late-1980s. Quagga mussels soon followed.

Great efforts have been made to prevent the spread of these fresh water mollusks west of the 100th Meridian. In January 2007, Quagga mussels were discovered in Lake Mead and later in other reservoirs of the Lower Colorado River. Quagga mussels were discovered by Metropolitan Water District divers on Wednesday, Jan. 17, 2007 at Lake Havasu, and again on Friday, Jan 19, 2007 about 14 miles to the north. In January 2008, Zebra mussels were discovered in San Justo Reservoir in San Benito County, California. The spread of these mussels to additional California waters will seriously impact the state’s aquatic environment and water delivery systems, endangering recreational boating and fishing.