Ready for return of the native oyster

Jeff Compton of the Nature Conservancy stands atop a Navy barge containing 500 cubic yards of oyster shells that will cover a two-acre bed in Liberty Bay near Poulsbo. Photo by Dean Rutz

LIBERTY BAY, Kitsap County — With a barge and a fire hose, friends of the Olympia oyster are helping the tiny shellfish make a comeback.

By sluicing more than 1,000 cubic yards of oyster shells into two acres of Liberty Bay, near Poulsbo, the volunteers and staff of the Nature Conservancy of Washington and the Puget Sound Restoration Fund are creating a fresh bed in the tidelands to encourage larvae of Puget Sound's only native oyster to set up housekeeping.

This effort here this month is just one of many going on around Puget Sound.

Once abundant, especially near its namesake of Olympia, the oyster was all but wiped out in the early 20th century by overharvesting and pollution. Today, Puget Sound is cleaner in many places than it used to be. But the Olympia oysters struggle against new foes.

With development on the land, excess nitrogen — largely from septic systems — creates algae blooms that die and settle on the bottom, creating a choking layer of mud that entombs the oyster reefs. And it also creates a slick, smooth surface that deprives oyster larvae of the habitat they need.

Young oysters, called spat, affix themselves to the craggy shells of their ancestors and begin the slow process of growing to maturity, which can take up to three years.

The much larger Pacific oyster, introduced from Japan for commercial harvesting, dominates in Puget Sound now.

Olympia oysters are still farmed commercially and survive in the wild in some protected coves and bays. But their small size — not even as long as a pinky finger — and their delicate pearlescent interior belie their powerful role in the ecosystem.

"It's a small oyster, but it has a big impact," said Betsy Peabody of the Puget Sound Restoration Fund.

Restoring ecosystem

In fact, the Olympia oyster is seen as key to restoring the natural functions of the Puget Sound ecosystem. Oyster reefs provide tiny hidy-holes for crustaceans and microorganisms that are food for salmon, herring, candlefish and even gray whales.

And as filter feeders, they can cycle up to 12 gallons of water a day, cleansing the Sound of sediment and excess nutrients.

As the water becomes more clear, it also allows more light to penetrate to the bottom, helping pastures of eelgrass to thrive.

The Puget Sound Restoration Fund chose Liberty Bay in part because Olympias have been found growing wild nearby. Now it's hoped that spat from those wild beds will seed the beds of oyster shells that are being laid for them.

This summer, three other areas will be prepared in a similar manner: Dogfish Bay, just around the bend from Liberty Bay, along with Woodard Bay and Frye Cove near Olympia.

Allowing wild Olympias to seed the areas themselves, instead of planting hatchery-raising spawn, will help preserve genetic integrity of native oyster populations, Peabody said.

Splitting the bill

It costs between $38 to $50 per cubic yard to spread the shells. The Nature Conservancy and other partners, including federal agencies and the Russell Foundation, a private nonprofit organization, are footing the bill.

Rebuilding the Olympia oyster is important for people, too.

"I've eaten Pacifics for probably 40 years; they are just kind of hamburger," said Brady Blake, a shellfish biologist. But Olympias? "I'll take them as No. 1, that's for sure," he said. "They are an uncommon treat."

Though not at risk of extinction, most Olympias are currently protected from harvest on public tidelands because they are so small.

Olympia oysters ...


• Are the only oysters native to the West Coast and to Puget Sound, ranging from Southeast Alaska to Baja California.

• Are about 2 ½ inches in diameter, much smaller than the common Pacific oysters, which were introduced from Japan for commercial harvest.

• Were once abundant, sustaining Puget Sound tribes for generations, but are no longer so.

• Can filter about 9 to 12 gallons of water a day.

Source: Puget Sound Restoration Fund, Nature Conservancy of Washington, Washington Department of Fish and Wildlife

Information

Nature Conservancy of Washington: www.nature.org/washington

Puget Sound Restoration Fund: www.restorationfund.org