Richmond volunteers are helping to bring hard-working oysters back to the bay

On a cool, moonlit autumn night, Aman Daro stepped carefully across a muddy bank of the San Francisco Bay. He was wearing waders to protect himself from the knee-deep mud. 

He knelt next to a man-made oyster reef and turned on his headlamp. After using a brush to scrub away mud and seaweed, he traced his finger along the structure, counting the number of oysters attached to the reef. The night sounded with the soft crash of the waves, the coos of nearby owls and the voices of several others nearby going through the same motions. 

The volunteers, eight in all, started counting the Olympia oysters in Point Pinole waters at dusk and continued well into the night, finishing three hours later at a second location. The molluscs once blanketed the Richmond shoreline, but their numbers have waned. 

As the volunteers worked their way through the intertidal zone, their headlamps bobbed, flickering like fireflies against the dark bay. 

The October count was Daro’s second time volunteering for The Watershed Project’s bi-annual community monitoring events, which occur in fall and spring to collect data on the Olympia oyster populations at the nonprofit’s restoration sites. 

“I really enjoy doing some sort of climate action and I felt this was a fairly easy and interesting thing to do on a lovely night,” said Daro, a former chief operating officer at a real estate company.

Oyster restoration along the Richmond shoreline has picked up in the past decade, not only to boost the Bay Area’s declining oyster populations, but also to help protect the coastline. 

Oyster reefs act as buffers, protecting coastal ecosystems and waterfront communities by reducing the impacts of waves and tides during storms. Oysters have other well-recognized benefits, such as creating habitats for other marine life and filtering pollutants and excess nutrients out of the water. 

Oyster restoration in Richmond

The Watershed Project launched its oyster restoration in 2013 to protect the Olympia oyster, the only oyster species native to the western United States. Since the Gold Rush, the species’ population has declined because of overharvesting, habitat loss, industrialization and a changing climate.

“A hundred years ago, the Olympia oyster was abundant, but right now it’s really, really low,” said Satoko Mills, environmental monitoring manager for The Watershed Project.  

Visit The Watershed Project’s website for more information about its restoration projects.

Olympia oyster populations are estimated to be at 1% of historic levels. In some areas, they are nearly extinct.  

Olympia oysters were naturally present by Point Pinole but didn’t have a hard surface to attach to, Mills said. So The Watershed Project installed 100 reef balls in the mudflats. They are made of concrete, sand and crushed oyster shells. About 3 feet high, the circular structures resemble large bells, with several holes to allow for water flow and a grooved surface to make it easier for marine life to attach themselves to them. 

For the past decade, the data that have been collected during the community monitoring events has allowed The Watershed Project to keep track of how the Olympia oyster population is doing. 

The most recent count is still being analyzed, but observations made by the volunteers indicate that the population is likely low. When closely inspecting the reef structures that October night, they noticed many of the mollusks had open or missing top shells, evidence of dead oysters. Mills estimates there were only about 10,000 to 15,000 oysters on the reef, based on data from the spring. The highest estimate the Watershed Project has observed in the last 10 years was 50,000. 

But Mills is not discouraged. 

“The oyster population goes up and down every year,” Mills said. “It’s a little hard to find a trend.”

The biggest drops have occurred when there is large input of fresh water, such as from the Bay Area’s heavy rainfalls in the past two years. When a large amount of fresh water enters the bay, its salinity can decrease dramatically, impacting the oysters’ health and ability to survive.

About an hour into their count, volunteers noticed the full moon slowly peeking over the horizon, and watched in awe as it rose above the bay. 

Na Omi Shintani, an artist on her first oyster count, stood up quickly to see it, but the deep sludge had suctioned her foot, causing her to tumble. Mud splattered across the backside of her waders and down her sleeves, prompting her to laugh as she accepted a hand to help her back to her feet. 

Shintani, who is Japanese American, comes from a family of oyster farmers who were forced  from their home in Washington state and incarcerated during World War II. 

“My dad always had great memories of it,” she said. “But he left there when he was 12 or 13, and they never went back to do oyster farming or that area.”

Shintani incorporates oysters into her sculptures and uses them to represent her family. Volunteering with The Watershed Project seemed fitting to her. 

“For me, it’s a way of connecting to my family history and imagining what they were doing,” she said. 

Coastal conservancy group testing use of eelgrass

In 2019, a separate shoreline restoration project was launched in Richmond by the California State Coastal Conservancy, which installed 350 reef structures in Giant Marsh at Point Pinole, and 200 at Point San Pablo. 

In addition, the conservancy planted several types of eelgrass alongside the oyster reef to test how the two species could help address sea level rise and shoreline erosion together. The largest eelgrass bed in the Bay Area lies between Point San Pablo and Point Pinole.

Just like oysters, eelgrass provides many benefits to the shoreline, including stabilizing sediment, reducing wave energy, decreasing coastal erosion and providing habitat for fish and other aquatic species. Eelgrass is also sensitive to many of the same stressors, such as climate change and sea level rise, which has led to a worldwide decline in abundance. 

The Richmond shoreline is a hub for the marine plant, supporting 70% of the eelgrass in San Francisco Bay, Keith Merkel said, speaking at a Richmond shoreline community event in September. Merkel is a principal consultant with Merkel & Associates, an environmental firm that has assisted with many eelgrass restoration projects in the Bay Area. 

This year, the conservancy concluded a five-year study to assess how its reef project was  faring. 

“Some of the big outcomes are that we did have good success with Olympia oyster recruitment,” said Marilyn Latta, project manager for the Coastal Conservancy. “We had over a million oysters estimated at the site at the height of the population.” 

But as The Watershed Project has found, heatwaves and heavy rain events hampered the oyster populations, resulting in complete loss at times, Latta said.

Recently, the conservancy has seen a resurgence, estimating there are around 350,000 oysters at the restoration site. 

“It’s definitely a dynamic population out there,” Latta said. 

The Watershed Project gives curious people of all ages and backgrounds a chance to monitor that population. But scientific observation can be tedious, which the October group found out as they made the mile-long slog back to their cars around 9 p.m., their legs and backs stiff from hours of crouching. 

“Everybody can do it,” Mills said. “You don’t need a science background. It’s just for fun.” 

Riley Ramirez is a journalism graduate student at UC Berkeley and holds a bachelor’s degree in environmental studies from the University of Washington.