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NRCS assists with restoration of Olympia oyster habitat

Barge placing Olympia oyster shells in Liberty Bay near Poulsbo, Washington
A barge places Olympia oyster shells in Liberty Bay near Poulsbo, Wash., Oct. 7, 2020. (Courtesy photo.)

The Puget Sound Restoration Fund (PSRF), a non-profit organization dedicated to restoring the Salish Sea, wrapped up the restoration of 100 acres of native Olympia oyster (Ostrea lurida) habitat in the Salish Sea in Oct. 2020, marking the completion of their goal which was started in 2010. The Salish Sea is the nation’s third largest estuary and home to the Pacific Northwest’s only native oyster, with an historic range from British Columbia to Baja California. In the Salish Sea alone, circa 1850, Olympia oysters covered 10,000 to 20,000 acres of intertidal area.

Unfortunately, due to over harvesting, pollution from early pulp mills, and habitat degradation, only 4% of the dense historic population remains. With limited habitat remaining, PSRF had to act fast. Brady Blake, Shellfish Biologist for the Washington Department of Fish and wildlife said, “While not a threatened or endangered species in Washington, the natural bed habitat they formed is vastly absent. While that habitat did not occur on the scales similar to that that of the Eastern oyster on our Atlantic and Gulf coasts, the localized habitat they provide in scattered Salish Sea embayments was certainly important locally to our marine ecosystem.” 

Restoring these oysters and their habitat provides many ecosystem services benefits. As their populations grow and spread, the tideland substrate stabilizes and becomes more resilient to wave action. In turn, these areas become a haven for smaller aquatic species in the nearshore, which provides necessary habitat for forage fish and salmon, several species of which are threatened and endangered. Increasing habitat for young salmon is a key component to recovering salmon populations. 

Olympia oysters are also extremely effective at cleaning and filtering pollutants from water. As filter feeders, Olympia oysters filter algae out of the water column, thus improving water quality and mitigating nutrient pollution that can degrade both water quality and habitat conditions over time.

The Olympia oyster has a strong connection to local Native American Tribes, who have lived in the Puget Sound region for thousands of years. The Olympia oyster is not only a staple food source but is also a culturally significant species to local Tribes. The Suquamish Tribe, along with others, have been working closely with the Natural Resources Conservation Service (NRCS) and PSRF on restoration efforts. 

Thanks to the help of partner programs like the USDA’s NRCS Environmental Quality Incentive Program, the PSRF reached their 100-acre goal in October of 2020 with the installation of 15 acres of clean oyster shell on a tide flat in Liberty Bay, Poulsbo, Washington. According to Betsy Peabody, Executive Director for PSRF, “the most critical aspect of this part of the project is making sure the shell is deposited in the right place, where conditions can support oysters long-term.” 

Betsy Peabody, Puget Sound Restoration Fund, and Frank Curtian, Natural Resources Conservation Service.
Betsy Peabody, Puget Sound Restoration Fund, and Frank Curtin, Natural Resources Conservation Service, stand along the shores of Liberty Bay near Poulsbo, Wash., Oct. 7, 2020. (Courtesy photo.)

Frank Curtin, NRCS resource conservationist, explains that “the [Liberty Bay] site was chosen because there was a small remnant population of Olympia oysters in an area with limited habitat structure.  Spreading shell in the lower intertidal area provides a structure that larvae can settle on, allowing them to re-colonize the area and expand over time.”

For three days in October 2020 a tugboat, a front loader, a water cannon, and a barge loaded with 1,500 cubic yards of shell were deployed in Liberty Bay. The tugboat operator and PSRF staff used GPS tracking to maneuver the barge within the designated enhancement plot. At high tide, the water cannon pumped sea water from below and sprayed the shell off the barge deck onto the tide flats, leaving the shell to slowly sink to the bottom where it will form a new reef-like structure. Now, instead of a mud-flat, there is an oyster shell under layer that will develop into a living oyster bed as generations of Olympia oysters settle and grow. 

“NRCS is excited to support restoration efforts that will benefit the health of Liberty Bay” says Curtin. He also states that he is “proud to see NRCS supporting the restoration of natural marine habitat; it’s not the typical type of agricultural production most people associate with NRCS programs.” 

In the years to come, PSRF, USDA, Tribes, and resource agencies will continue to look for opportunities to rebuild Olympia oyster populations in priority locations to re-establish this foundational part of a healthy marine ecosystem. “PSRF gratefully salutes NRCS for all their support over the past 10 years on this important habitat restoration project” said Peabody.