Native Building Blocks of California’s Estuaries
Illustration by Laurie Sawyer
Four small oysters in a human hand
Photo by Ralph Pace

The Small but Mighty Olympia Oyster

It is not any oyster that gets a nickname, but the diminutive, native oyster of the Pacific Coast of North America does. Oly (Oh’-lee) is a moniker of affection for the Olympia oyster, or more formally, Ostrea lurida. Though small and often hidden from view, Olys are powerhouse players in rebuilding resilience and biodiversity along the shorelines of the bays that so many humans call home. Olys can be heroes in helping estuaries adapt to a changing climate. We should know more about them. Why Olys?

California’s Estuaries are Essential

An oyster’s home is in an estuary. Oyster beds are one of several iconic habitat types found in the sheltered waters of estuaries, along with eelgrass beds and salt marshes. These foundational habitats make estuaries some of the most productive zones for life on Earth. California has many of these biodiverse estuaries, but San Francisco Bay is by far the biggest. It is a complex matrix of river, ocean, marsh, mud, city, and suburb; it is a downtown and a remote refuge, it is a transcontinental shipping lane and a quiet fishing pier. It is all of these things, and it is the Olympia oyster’s home. Learn more about Estuaries and the San Francisco Bay.

California is an ocean state. It has about 1,270 miles of open ocean coast from the Oregon border to Tijuana, Mexico. It has about the same length of more sheltered and estuarine shorelines in San Francisco, Humboldt, and San Diego Bays, together with numerous smaller estuaries, lagoons, and river mouths. Almost 70% of California’s population lives in counties bordering the coast and estuaries, concentrated around San Francisco Bay and in the Los Angeles-Orange-San Diego Counties.

Map: ESRI and USGS
illustration show various species in estuary
Illustration by Laurie Sawyer

Olys: Laying a Foundation for a Whole Community

The Oly community at the edge of the Bay—either along the shoreline or in deeper submerged areas—is an alluring world. It is a wondrous mashup of diverse organisms, from slippery green seaweed, darting herring, settling crab larvae, stalwart eelgrass, clams and worms in the mud below, and birds of all sorts coming into the shallow waters from above. We humans are very much a part of this community. Come explore ten key characters in the Olympia oyster’s unfolding drama, and discover how the intricate web of connections this little, flat bivalve embodies is vital to the future health of the San Francisco Bay. The Oly Community

“The tidelands—the lands exposed by low tide and covered by high tide—have a unique role in the region’s legal, economic, and social history. Enormously productive of fish and wildlife in their unaltered state, San Francisco Bay’s tidelands were also the most coveted real estate in the American West.”

—Matthew Morese Booker, Down by the Bay: San Francisco’s History between the Tides

Visit The Illustrious History of Olys in San Francisco Bay

Tools made of oyster shell and other elements

Lost World: 5,000 years of Art from the Bay Area Shell Mounds

Photo by BAMPFA

Food & Culture

Oysters have been part of the human story since the very beginning: as prehistoric food pathways to brain development of Homo sapiens, as signifiers of place within shellmounds, as decorative shell embellishments to California Indian regalia, or as enticing lures for a weekend jaunt to slurp oysters beside the beautiful Tomales Bay. The evolving relationship between oysters and humans is a fascinating and ongoing story. Food and Culture.

Olympia oyster restoration project in Elkhorn Slough using clamshell “necklaces.”

Photo by Kerstin Wasson

Experiments in Oly Recovery

Dozens of researchers and advocates have been working on native oyster restoration around San Francisco Bay for decades, though this work, like the low-profile Oly itself, often remains under the radar. Each restoration site is an opportunity to learn, iterate, and develop best practices. The Living Shorelines Projects promote a holistic approach by enhancing eelgrass, oysters, seaweeds, and marsh vegetation to create a mosaic of habitats that can effectively address sea level rise. Learn about six restoration sites around The Bay Area. Restoration