Volunteers spreading shells in Discovery Bay
Olympia Oyster Restoration

Olympia Oyster Restoration

The Olympia oyster (Ostreola conchaphila) 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 Discovery Bay. Scattered individual Olympias can be found in other bays in Jefferson County.

Discovery & Quilcene Bay Projects

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 remnant population cluster. 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 a 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 2016 the MRC started test plots in Quilcene Bay to see if we could expand our Olympia Oyster project to a second bay in our County that historically had a thriving Olympia oyster population. After 2 years of subsequent monitoring, we determined that this particular location is not suitable and will be exploring new options for project sites in 2020.

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

2018 Discovery Bay Monitoring

We've seen good progress at our Discovery Bay project site. Volunteers were out in July 2018 monitoring the 2014 habitat enhancement area. We counted and measured 732 oysters. Smallest ones (this year’s spat) were 5 mm, and the largest one was 75 mm long!

See the 2018 Olympia Oyster Summary Report here. (Data sheets not included.) We added more shell to a nearby area in 2019, and hope to add more shell in 2020.

2018 in 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 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. We monitor these test plots annually. See the 2018 Olympia Oyster Summary Report for info on both Quilcene and Discovery Bay monitoring.

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, Beachwatchers,  Shore Stewards and others, the Jefferson MRC also conducted presence/absence surveys beaches in 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.

Related: Read the Discovery Bay Olympia Oyster Research Project 2010 Field Season Summary Report found in the Northwest Straits Resource Library

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