Oyster reefs protect against floods, wave surges, and coastal erosion due to rising sea levels caused by climate change, act as a habitat for hundreds of species, and filter water. They’re not just food. So, oyster reefs are being built from New York, the Pacific Northwest to California to replenish the mollusks, which have been decimated by industrialization and pollution for decades.
“We consider oysters an umbrella species – focusing conservation efforts on restoring oysters and their habitat indirectly benefits a broad array of other species in the ecosystem,” says Jonathan Young, a wildlife ecologist in San Francisco at the Presidio, which has an oyster restoration project.
“Oysters are environmental engineers: they enhance and modify the environment, their reefs and beds create complex nooks and crannies where small fish, crabs and other invertebrates can hide, nest and grow, and they also filter particulates from the water.”Jonathan Young, wildlife ecologist
Oysters & New York City
In New York City, The Billion Oyster Project has restored 75 million native oysters in 15 reefs from Brooklyn to the Bronx so far. Their ambitious goal: to restore a billion oysters to New York Harbor by 2035.
The citizen science project has nine field stations from Coney Island Creek, Brooklyn Bridge Park to Far Rockaway’s Bayswater Point State Park, over 10,000 local volunteers, and partners with 100 schools and 75 restaurants. Restaurants donate used oyster shells, students help do oyster installations and their schools “adopt” stations to manage oyster cages and collect data since the project’s founding in 2014.
New York has a rich oyster culture history. Its harbor was the world’s biggest source of oysters in the 19th century, providing about half its supply – six million oysters were transported on any given day.
Oysters were so plentiful and cheap, they were even eaten by the working class and poor, with none of the snob appeal they have today. Restaurants at all price points served them; the most iconic, Grand Central Oyster Bar, opened in 1913 inside Grand Central Terminal railroad station.
But it took less than a century to nearly wipe out the oyster population in New York Harbor. In 1849, the city began building sewers that dumped raw sewage into the harbor, which rapidly became a polluted mess. But today, the harbor is the cleanest it’s been in over a century, thanks to the Clean Water Act of 1972.
Oysters on the West Coast
On the West Coast, the Native Olympia Oyster Collaborative is a network of academics, practitioners and managers involved in oyster restoration projects from British Columbia to Mexico’s Baja California for the Olympia oyster (Ostrea lurida), which is native to North America’s Pacific coast. Over 40 restoration projects, such as Washington State’s Puget Sound, California’s San Francisco Bay, Humboldt Bay and Newport Bay and Oregon’s Coos Bay are described on its story maps.
In Washington, Puget Sound Restoration Fund met its 10-year goal to restore 100 acres of Olympia oyster habitat in 2020. When the Seattle-based nonprofit began its efforts, native oysters numbered in the hundreds in Puget Sound, and only about 150 acres of dense oyster clusters were left; in contrast, there were 10,000-20,000 acres of oyster habitat before white settlers came in the 19th century, estimates the Washington Department of Fish and Wildlife (WDFW). But by 2017, over six million Olympia oysters abounded in Puget Sound.
Baby oysters like to attach to hard surfaces like shells and rocks. After experimenting in many locations, the Puget Sound nonprofit found the best way to grow them was to use shells from Pacific oysters (a non-native species, found on temperate coasts worldwide but native to Asia’s Pacific coast, which accounts for 98% of the world’s commercially-farmed oysters).
They transferred both seeded oysters set in Pacific oyster shells and adult Olympia oysters to prime locations and added “shell enhancements,” Pacific shells for larval Olympias to latch onto. In its final project, and biggest “shell enhancement,” a pump on a barge sprayed 1,500 cubic yards of Pacific shells over 15 acres in Dogfish Bay, a small bay within Liberty Bay outside Poulsbo in Kitsap County.
Below is a video of Puget Sound’s oyster restoration work, accomplished with help of partners from USDA Natural Resources Conservation Service, WDFW, Native American tribes, foundations, universities to shellfish growers. Their next goal: restore 50 more acres by 2035.
Native oysters have been important to Native American tribes, both culturally and environmentally, for thousands of years. So, native oyster habitat restoration was “a very powerful thing to do. It’s part of our identity, our world,” Skokomish cultural resources technician Genny Rogers told The Kitsap Sun in 1999.
The West Coast presents more challenges, says Edwin Grosholz, professor of environmental science and policy at University of California at Davis. Olympia oysters, much smaller than oysters on the East and Gulf Coasts (called eastern or Atlantic oysters, Crassotrea virginica), found from Massachusetts, Chesapeake Bay, Virginia, New York, northern Florida to Louisiana, build shallower beds instead of tall reefs. Their impact on water quality is less since tidal exchanges are much greater in western estuaries, while water stays in eastern estuaries much longer, he explains.
San Francisco Bay’s oyster efforts
Today, oyster habitat in San Francisco Bay is about 1% of what it once was, experts say. It’s one of the nation’s most urbanized estuaries, packed with cities, and depletion began in the Gold Rush, from 1849 on. To make things worse, climate change is “squeezing” oyster habitats since warmer and more acidic ocean water causes problems. So, oyster restoration is a “win-win both for the environment and human infrastructure, since oysters are such a key part of the food web,” says Grosholz, who oversees and studies oyster restoration projects in San Francisco Bay and Marin County’s Tomales Bay.
In a new project begun in late 2020 in San Francisco’s Presidio, a large park managed by the National Park Service and the Presidio Trust, another Federal agency, oysters are growing in all three reef types installed. Bags of oyster shells, reef balls (cement mixed with oyster shells) and fiberglass panels were installed at Quartermaster Reach, which extends from a freshwater stream to salty Crissy Marsh on the edge of the bay.
Oysters are “the working class stiffs with a huge role to play to make our Bay cleaner and more resilient to rising tides caused by climate change,” says Linda Hunter, founder of Wild Oyster Project, a nonprofit working on oyster conservation in San Francisco Bay that’s a project of Earth Island Institute, founded by legendary environmentalist David Brower.
So, consider the oyster, thank it next time you see it, and compost or donate your used shells instead of throwing them away.