A massive amount of oyster shell — some 1,500 cubic yards — will be dumped into Sinclair Inlet near Gorst next week to lay the groundwork for a healthy population of native Olympia oysters.
Limited numbers of Olympia oysters have been growing in Sinclair Inlet, hanging on since long ago, said Betsy Peabody, executive director of Puget Sound Restoration Fund, which is managing the operation. Existing oysters probably just need the right substrate for their larvae to attach, grow and ultimately expand the native oyster population.
The $300,000 project — which will deposit the equivalent of 150 dump-truck loads of Pacific oyster shells — will be the largest one-time application of shells anywhere in Puget Sound, Betsy told me. Her organization has undertaken similar projects in other areas, including Liberty Bay near Poulsbo, Dogfish Bay near Keyport, Dyes Inlet near Bremerton and Port Gamble Bay on Hood Canal.
Map: Puget Sound Restoration Fund
The shells, which came from commercial oyster farms, will be washed off a 200-foot barge using a jet of water beginning Tuesday and taking up to four days, according to the current schedule. The shell will cover some 15 acres of tidelands toward the middle of the inlet where Highway 166 branches off Highway 16.
This washing process typically creates a patchwork of shell covering about 80 percent of the bottom while 20 percent remains bare, according to plans for the project. The thickness of shell on the bottom will vary, reaching up to 3 inches in some places. No eelgrass or other sensitive vegetation was found during surveys of the tidelands to be covered. The property is owned by Kitsap County.
Map: Washington Department of Fish and Wildlife
In the early 1900s, Sinclair Inlet was used as an 122-acre oyster reserve for protecting seed stock, which could be purchased by commercial oyster growers. Oyster reserves throughout Puget Sound were largely forgotten after Pacific oysters — a different species imported from Japan — began to dominate the oyster market.
Olympias went extinct in some areas, killed by pollution, shoreline development or other factors. In a few areas, habitat was largely undisturbed and the original oyster species persevered. But many embayments, including Sinclair Inlet, were able to support only a fraction of their historic populations.
“Olys evolved in this area and managed to maintain a foothold in the most surprising areas, despite what we’ve thrown at them over time,” Betsy said. “They are tough little critters. You can even find them in places where everything else is plastic. Building back their densities seems like a good thing to do.”
Oysters have a number of good qualities besides being a favorite food of many people. They can filter out plankton that can trigger low-oxygen conditions. Plankton also reduce sunlight needed for critical vegetation, such as eelgrass.
Map: Washington Department of Fish and Wildlife
Washington Department of Fish and Wildlife has designated Sinclair Inlet as one of 19 priority restoration sites for Olympia oysters in the Puget Sound region. See “Plan for Rebuilding Olympia Oyster (Ostrea lurida) Populations in Puget Sound…”(PDF 559 kb)
In natural oyster beds, young oysters are able to set and grow on the shells of their ancestors, often forming oyster beds or reefs that help perpetuate the substrate for future generations. Sedimentation and damage to the shoreline can interrupt the process and eliminate the substrate needed for the oyster to survive. Putting down a lot of shell to create new substrate has proven to be the best way to boost the population in most areas of Puget Sound.
If the Olympia oysters do well in Sinclair Inlet, eventually more shell could be brought in to expand the growing area, Betsy said. If, however, natural production of oyster larvae is not enough, PSRF could develop a broodstock program by utilizing its shellfish hatchery near Manchester, as has been done for other areas. If that were to happen, adequate numbers of Olympia oysters from Sinclair Inlet would be used to produce the oyster seed, thus maintaining the genetic diversity of the inlet.
In 2010, Puget Sound Restoration Fund established a goal of restoring 100 acres of Olympia oyster habitat with shell placed in bays where the native oysters are expected to do well. The Sinclair Inlet project will bring the total to 85 acres, with other areas in the planning stage to help the group meet its goal by the end of next year.
About half of the $300,000 being used for the Sinclair Inlet project came from the federal Natural Resources Conservation Service, with other funding from the Washington Department of Ecology, Kitsap County and PSRF. The Suquamish Tribe also participated in the project.
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