Volunteers spreading shells in Discovery Bay
Olympia Oyster Restoration

The Olympia oyster (Ostrea lurida) is the native oyster of the Pacific coast of the US. Due to habitat loss and overfishing, the populations of this oyster are a fraction of what they were 150 years ago. One small but persistent population of Olympia oysters is located in Jefferson County's Discovery Bay. Scattered individual Olympias can be found in other bays in Jefferson County.

Project Overview

Olympia oysters are ecosystem engineers, forming complex carpets of overlapping shell that provides hiding places and feeding opportunities for a diverse community of nearshore species. The MRC has been working for over 10 years to protect the Discovery Bay population and restore Olympia oysters to local waters. In the early years, our work included surveys, educational outreach and monitoring studies in Discovery Bay. 

In 2013, the MRC began a 1/2-acre habitat enhancement project in Discovery Bay near a stable but small population of Olympia oysters. This extant population was doing well, but had not expanded much due to limited availability of suitable substrate (especially oyster shells) in the area. In August 2014 volunteers dispersed clean Pacific oyster shells (not seeded with oyster spat) onto ¼ acre of tide flats nearby. We wanted to test the effectiveness of  ‘light touch’ restoration by adding scattered shell, but not a thick layer. Larvae released from the nearby population settled on this shell in 2015 and 2016. Additional shell was added to the project site in 2016 to replace the shell that the tides had moved elsewhere. MRC volunteers have been monitoring this site every year. The Olympia oysters are definitely settling and growing on the shell we put out. 

In 2019, with agency permits in hand, we added clean oyster shells to a new area nearby, hoping Olympia oyster spat would also settle here. On a preliminary fall 2019 reconnaissance, we found Olys settling on the shell we'd placed. We'll monitor this new site in 2020 after the shell has been in place for a full year.

Oyster shell was delivered by boat in net bags on the previous day's high tide
Discovery Bay project site after 2014 installation

Discovery Bay Monitoring

We've seen good progress at our Discovery Bay project site. Volunteers have been out every summer monitoring the 2014 habitat enhancement area. 

See the 2019 Olympia Oyster Discovery Bay Summary Report here for more details. We will be adding more clean shell every few years to build up a large enough substrate base for a stable population. Adding additional shell annually over several years is a good strategy for stabilizing the project area, as some shell will always sink into the sediment or be moved by currents into adjacent areas.

In 2019 we also added 112 bags of clean shell (cultch) to a second area near the original population and will continue adding shell annually for the next few years.

Restoring Olympia oysters in Discovery Bay

Quilcene Bay

In 2016, the MRC worked with WDFW and Tribal shellfish biologists to establish new test plots in Quilcene Bay. Here, where there is no existing, high-density Olympia oyster population, we tried "planting" seeded cultch (Pacific oyster shell with newly settled Olympia oyster spat already on it) in one small area of the bay to see if they might survive and grow. Wild-seeded cultch donated by Taylor Shellfish and hatchery-grown cultch purchased from Puget Sound Restoration Fund were set in place in 2017-2018. 

After 2 years of subsequent monitoring and very little survival, these test plots provided us with the info we wanted--this particular location was not suitable for Olympia oyster restoration work. Quilcene Bay is a large bay, however, and the Puget Sound Restoration Fund is already exploring other, more promising sites for restoration.   

Part of a Regional Effort

Olympia oyster restoration is happening all along the west coast of North America. A 2018 Story Map  by the Native Olympia Oyster Collaborative illustrates how many groups are working on Olympia oysters. There are over 15 different sites listed, including projects with Skagit, Whatcom and Clallam Marine Resources Committees.

Previous Work

Beginning in 2007, the MRC monitored the population in Discovery Bay, recording information about geographic location, estimated numbers of individuals, size distribution, age, and larval settlement.

Partnering with WDFW, Beach Naturalists, Shore Stewards and others, the Jefferson MRC also conducted presence/absence surveys at beaches across Eastern Jefferson County.  Below is a quick video showing how to identify Olympia oysters and how the surveys were conducted. Additional information can be found at the Puget Sound Restoration Fund web site.

Olympia Oyster Training: Fun day on the beach!
Olympia Oyster Restoration