Olympia oysters were once the pride of the West Coast, beloved for their clean, tangy taste. Pollution and over- harvesting nearly wiped out the tiny native bivalve, and development has led to a thick layer of muck on the floor of the inlets where they once thrived.

However, The Nature Conservancy thinks there may be sufficient remnant Olympia oysters to repopulate those inlets, if only they have a hard substrate on which they can attach.

What the Conservancy is Doing

At Woodard Bay, on Henderson Inlet near Olympia, The Nature Conservancy is in the third year of a pilot project to create better habitat for Olympia oysters by laying down a substrate of clean Pacific oyster shells.

In our featured video, Conservancy scientist Betsy Lyons explains that this year we’re primarily monitoring the condition of the shell substrate- how much has sunk, and how much has been covered by other organisms.

More About Woodard Bay

Woodard Bay is one of three sites in Puget Sound where the Conservancy is working with Puget Sound Restoration Fund and other partners to create these new oyster shell beds. Woodard Bay is an unusual project because we’re leasing submerged lands from the state Department of Natural Resources to do conservation work. We’re also working with DNR within the Natural Resources Conservation Area.

This is the first place in the country where marine conservation leases have been used, and conservationists all over the world are looking to see if they can adapt this program to their local marine conservation efforts.

Why Oysters Are Important

Oysters are a critical component in marine water quality. Each Olympia oyster has the capacity to filter between 9 and 12 quarts of water a day, straining out phytoplankton and cleaning the water. The oysters continue to grow and create their own beds that provide food and shelter for crabs, anemones, and other marine life.

By encouraging the existing wild population of Olympia oysters to thrive and expand, rather than seeding the beds with commercially grown Olympia oysters, we hope to maintain genetic diversity.

Washington oyster projects are largely funded through the National Oceanographic and Atmospheric Administration (NOAA) Community Based Restoration Program, with additional funding from the U.S. Department of Agriculture’s Natural Resources Conservation Service, state Department of Ecology Coastal Protection Fund, The Nature Conservancy’s Global Marine Initiative, the Russell Family Foundation, and other private and public sources.

Oyster Life Cycle

The oyster initially spawns as a male, and then alternates its functional gender between each spawning cycle. Spawning begins when the water is between 55 and 60 degrees F. The males release clusters of sperm into the mantle cavity. These sperm balls disintegrate in seawater and release the spermatozoa, which are then brought into the mantle cavity of the female with water pumped by the gills, and the eggs are fertilized.

Fertilized eggs develop into larvae in the oyster’s mantle chamber before they are discharged 10 to 12 days later. An average brood of larvae is 250,000 to 300,000. Eleven to 16 days later, the larvae develop an eyespot and foot and begin to crawl on hard substrate, and then metamorphose into spat. (That hard substrate is what we are laying down in Woodard Bay.)

Olympia oyster spat most often set on the underside of horizontal surfaces. This is attributed to the swimming position of the larvae in which the foot is held in a superior position. The oyster crawls with the foot on the surface and secretes glue from the byssus gland, which attaches the shell to the substrate.

Nature picture credits (left to right): Photo © Jocelyn Ellis/TNC (Woodard Bay); Photo © Robin Stanton/TNC (Besty Lyons); Photo © Robin Stanton (Betsy Lyons).