Recovery of the Olympia Oyster in Kitsap
Barge loaded with 500 cubic yards of Pacific oyster shells will become
the remnant shells oyster larvae attach to for their growth cycle.
Kitsap County, near Poulsbo
Wildlife Habitat Incentives Program (WHIP) funds, along with monies provided by
several other partners, were used to help restore habitat for the Olympia Oyster
in Liberty Bay.
There were many partners involved in this project. The Natural Resources
Conservation Service (NRCS) worked with the Puget Sound Restoration Fund (PSRF),
The Nature Conservancy (TNC), and the Washington Department of Fish and Wildlife (WDFW)
who owned the property. The Hood Canal Oyster Company donated equipment and
operators, and the Russell Foundation provided additional funding.
Once an abundant shellfish in the Puget Sound, the Olympia oyster was decimated
in the early 20th century by overharvesting and pollution. With increased
development around Puget Sound, excess nitrogen (largely from septic systems)
created algae blooms which died and settled to the bottom, covering the oyster reefs.
This caused a smooth, slick surface that is uninhabitable by the oyster larvae.
Young oysters attach themselves to the jagged surface of remnant shells and
slowly grow to maturity, taking approximately three years. Because of the unique
nature of this growth process, discarded shells of processed oysters is a
valuable resource for maintaining optimum habitat for oyster spat. Each oyster
can filter 9-12 gallons of water per day through their feeding process, making
the Olympia oyster one of the keys to restoring the natural functions in the
Using WHIP funding, along with monies from partners and organizations, Betsy
Peabody with PSRF was able to organize the efforts of many people to make this
project a success. Jim Hayes, owner of the Hood Canal Oyster Company, used his
boat to push the barge, donated by the US Navy, filled with oyster shells to the
spreading area. Once on site, several volunteers took a turn at the water cannon
which was used to "wash" the shells off the barge and into the sound. The cost
of spreading the shells was approximately $38 per cubic yard. WHIP
contributed 75 percent towards the purchase of shells, hauling them to the site, and
spreading them across the oyster beds. About 1000 cubic yards of shells
were spread on two acres of WDFW tideland creating a "shelf" for the young oysters
to grow and develop.
The PSRF chose Liberty Bay for oyster recruitment because of the small clusters
of Olympia oysters found growing nearby. The plan is for spat from wild oyster
beds to seed this new bed being developed. According to Peabody, allowing the
wild Olympians to seed the area themselves instead of planting hatchery-raised
spawn will help preserve the genetic integrity of the native oyster population.
These oyster reefs are important not only as oyster habitat but they also
provide an environment for crustaceans and microorganisms that are food for
salmon, herring, candlefish, and even gray whales. "Overall it is a small oyster,
but it can have a huge impact on the health of an estuarine ecosystem such as
Liberty Bay," she said.
Through studies in two other areas of the Hood Canal, it was determined that at
least 8" of oyster shell was necessary to overlay the mud substrates effectively
requiring 500 cubic yards per acre of shell fragments. WDFW biologists have been
monitoring the site since it was treated ten months ago. According to WDFW,
oyster spat densities have increased considerably with counts of 10-12 oysters
per square meter. Monitoring efforts in the years ahead will clearly enable
additional estimates of native oyster abundance for this site.
Dan Larsen, Soil Conservationist (360) 337- 4433
NRCS, Spring 2008
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