Some people shiver eagerly in anticipation of a delicious oyster. Others shiver with disgust at the thought. But whether you prefer to chew them, swallow them whole, or just skip them and move on to dessert, oysters offer something for everyone.
Oysters are filter feeders. An adult oyster can filter 25 gallons or more of water per day in search of food. In doing so, they filter algae from the water, reducing nutrient loads and keep bay water clear so that eelgrass and other marine life can thrive.
All things being equal, more oysters equal cleaner water for everyone. Conversely, fewer oysters means our bays and estuaries are worse off. And if water is too polluted, the oysters living in it can be poisonous for us eat.
Besides the essential job of filtering water, oysters provide habitat for myriad other species. As they grow in clumps and form larger reef structures, they provide homes for invertebrates like crabs, shrimp and other shellfish, as well as the small and juvenile fish so essential to the marine web of life that we rely on.
CORNERSTONE OF COASTAL CULTURE
Oysters have long been important to coastal communities. Here in Washington, there once were abundant oysters in the shallow bays and estuaries of Puget Sound and Willapa Bay. These were the Olympia oyster, the only oyster native to Washington – in fact, the only one native to the West coast of North America.
Native people enjoyed abundant wild oysters. Commercial harvest was largely spurred by the California gold rush in the mid 1800s; as oysters were depleted in California’s waters, people sought and found them farther north. It didn’t take long for our Olympia oyster beds to be picked clean.
As native oysters became scarce, non-native ones were imported from the east coast and Japan. Soon a thriving and world renowned Washington oyster industry was established.
ENGINE OF ECONOMY AS WELL AS ECOLOGY
Oysters are part of a huge shellfish industry in Washington and throughout the coastal United States. According to the Pacific Shellfish Institute, “Washington State is the largest producer of bivalve shellfish product in the United States, generating nearly $100 million in sales and accounting for 86 percent of the west coast’s production in 2005.”
Most of the oysters cultivated in Washington waters are non-native, the Pacific oyster being the most common. But the Olympia oyster is still cultivated and is hopefully poised for a comeback – with some help. They are all good neighbors, doing their part to make our saltwater bays and estuaries cleaner.
These bays and estuaries are known to connoisseurs. Oyster lovers appreciate the qualities that differentiate the shellfish grown in Hood Canal from those in North Puget Sound, South Puget Sound or Willapa Bay.
Wine lovers may be familiar with the concept of “terroir.” Like wines, oysters are sought not only for their species (as in kind of grape), but also for the flavor imparted by where they grew. Salinity, minerals and available food all affect the flavor of an oyster.
Hope on the half shell
Six years ago, The Nature Conservancy published a global review of the status of native oyster reefs, once one of the most common and important habitat types in temperate coastal areas throughout the world. We estimated then that 85% of oyster reefs had been lost—even greater than the losses reported for other important marine habitats including coral reefs, mangroves, and seagrasses. Although oyster reefs are receiving more conservation attention now, they remain an obscure ecosystem component and still are vanishing in some places at alarming rates.
When we lose mature shellfish beds and reefs, we lose more than a tasty kind of seafood. Conserved and managed well, native oyster beds will build up layers of dead shell, creating a structure that other marine animals can hide in or grow on. As the live oysters in the top layers grow and multiply, they filter large amounts of algae and plankton from the seawater around them, making it clearer and cleaner. These “ecosystem services” provided by shellfish are important to the health of estuaries and bays in Puget Sound and along the Washington Coast.
Farmed shellfish beds can provide many of the same ecosystem services as natural beds and reefs. In Willapa Bay, for instance, we know that farmed oyster beds are the habitat type most preferred by juvenile Dungeness crabs. Those juveniles move offshore when they mature, and Willapa Bay and Grays Harbor together produce about 30 percent of the Dungeness crab caught off of Washington’s Pacific Coast. The fishery on Dungeness crab in 2010-11 produced almost 22 million pounds, for a dockside value (the price paid to fishermen) of more than $61 million.
Shellfish help keep estuaries and bays healthy
So, if we want healthy estuaries and bays, as well as great eating oysters, we need to take care of both our native shellfish habitats and a clean coastal environment that supports shellfish farming. Shellfish growers and The Nature Conservancy have been at the forefront of protecting coastal habitats and water quality in places like Willapa Bay (located near the Conservancy's Ellsworth Creek Preserve) and Hood Canal. The Conservancy, shellfish growers, and other partners like the Puget Sound Restoration Fund and Washington Department of Fish and Wildlife have also worked to restore wild, native oysters in the bays of Puget Sound.
These efforts and other shellfish-related projects in Washington are coordinated through the Washington Shellfish Initiative, a collaboration of the Governor’s Office, state and federal government agencies, the shellfish industry, and environmental organizations. Beyond Washington, The Nature Conservancy is working with similar partners and volunteers to restore oyster reefs along the south Atlantic and Gulf coasts.