Olympia Oyster

The Science

Glane23, Flickr

Taxonomic description

  • A marine bivalve mollusk, in the marine invertebrate group along with other oysters
  • Often reaches 6-8 cm (2.4-3.1 inches) length and 2.5-3.5 cm (0.90-1.3 inches) thick [1]
  • Shell shape variable, often forming to the shape of the surface on which it grew[1]


  • Found on the west coast of North America, from southern Alaska to Baja California, Mexico [1,2,3]

Life history

  • Spawning is triggered by water temperature of 16-18C (60-64F) and can occur 1-2 times per year between spring and fall [1].
  • Broods; fertilized eggs develop in the female mantle [1]
  • An average brood of larvae is between 250,000-300,000
  • Maximum age is unknown


  • Lives in estuaries, sounds, tidal channels, and bays.
  • Filter feeder, eats microscopic algae and plankton [3]
  • Many predators including birds, rays, and rock crabs.
  • Sensitive to water temperature changes, but can tolerate short exposure to changes in salinity [1]
  • Large amount of its natural habitat has been removed to due urban development and pollution [2]

The Fishery

The Nature Conservancy, Youtube

Seasonal availability

  • Shellfish farms often provide year round availability.

Managing authority

  • Farmed with strict governing by Federal Agencies: NOAA, Army Corps of Engineers, Fish and Wildlife Service, USDA, EPA, FDA, BOEM, and the Coast Guard [11]
  • In states where recreational shellfishing is common, the state Department of Fish and Game regulate seasonal harvest [5]
  • In Washington state, the minimum size for oyster harvest is 2.5 inches.  The large minimum size is thought to prevent much collection of the oyster [5]

Gear type

  • Oyster farming in the U.S. began in 1890s in Puget Sound tidelands [6]
  • Oysters are grown by on-bottom, off-bottom or suspended culture methods [11]
  • The standard marketable size of an Olympia oyster is about the size of a silver dollar (3.5-4 cm) [6]

Status of the fishery

  • Native American harvested Olympia oysters for food [6]
  • Production peaked from 1890s to 1900 but greatly declined after due to pollution and over harvesting [6]
  • Larger, faster growing species, like the Pacific Oyster from Japan, continue to dominate oyster farming in the U.S. [7]
  • It takes 3-5 years for an Olympia oyster to reach market size [6,7]
  • A growing interested in the local food movement has increased interest in the Olympia oyster [10]

Potential ecosystem impacts

  • Oyster farms have minimal impacts to local ecosystems. [9]
  • Oyster beds provide many ecosystem benefits such as: habitat for other species, improved water quality, biodiversity support, reduced shoreline erosion, and enhanced restoration projects [8]
  • Monterey Bay Aquarium’s Seafood Watch classifies farmed oysters as three of its “Best Choices” for seafood options [9]

The Seafood


Edible portions

  • Everything but the shell is edible and is typically prepared
  • Oyster shells should always be tightly closed prior to preparation [12]

Description of meat

  • Olympia oysters have a bright, earthy, coppery taste [13]; sometimes described as peppery

Culinary uses

  • Local Olympia oyster is often available fresh from the farm.
  • Shucking the shell is manageable. Instructions can be found in multiple online resources  (e.g., [15])
  • Olympia oysters can prepared many ways: Freshly on the half shell, fried, steamed, smoked, in soups and stew, and more [13]

Nutritional information  

  • Low calorie, easier to digest than red meat, and high in vitamins [14]
  • Raw Pacific oyster (50g or 1.8oz) [16]


[1] Couch, D. and T.J. Hassler. 1989. Species profiles: life histories and environmental requirements of costal fishes and invertebrates (Pacific Northwest) —Olympia oyster.  U.S. Fish Wild. Serv. Biol. Rep. 82(11.124) U.S.Army Corps of Engineers, TR EL_82-4. 8pp.

[2]Timmins-Schiffman E, Friedman C, Metzger D, White S, Roberts S. Genomic resource development for shellfish of conservation concern. Molecular Ecology Resources [serial online]. March 2013;13(2):295-305. Available from: Academic Search Complete, Ipswich, MA. Accessed May 13, 2014.



[5] Washington Dept. Fish & Wildlife. http://wdfw.wa.gov/fishing/shellfish/ps_clam_oyster_faqs.html

[6] Couch, D. and T.J. Hassler. 1989. Species profiles: life histories and environmental requirements of costal fishes and invertebrates (Pacific Northwest) —Olympia oyster.  U.S. Fish Wild. Serv. Biol. Rep. 82(11.124) U.S.Army Corps of Engineers, TR EL_82-4. 8pp.

[7] Beahrs, A. (2012). Heaven on the Half Shell. Smithsonian, 43(3), 62-69.

[8] NOAA - Oyster Restoration - http://www.habitat.noaa.gov/restoration/techniques/oysterrestoration.html

[9] Seafood Watch 2014  HYPERLINK "http://www.seafoodwatch.org/cr/seafoodwatch/web/sfw_factsheet.aspx?fid=82"http://www.seafoodwatch.org/cr/seafoodwatch/web/sfw_factsheet.aspx?fid=82

[10] Sunset Magazine.  Christopher Hall, The West Native Oyster Makes a Comeback.  HYPERLINK "http://www.sunset.com/travel/northwest/olympia-oyster"http://www.sunset.com/travel/northwest/olympia-oyster

[11] FISHWATCH. U.S. Seafood Facts. NOAA.  HYPERLINK "http://www.fishwatch.gov/seafood_profiles/species/oyster/species_pages/p..."http://www.fishwatch.gov/seafood_profiles/species/oyster/species_pages/p...

[12]  Pacific Coast Shellfish Growers Association- PCSGA. http://pcsga.org/buying-tips/

[13] Taylor Shellfish Farms. http://www.taylorshellfishfarms.com/about-our-shellfish.aspx

[14] Sea Grant Washington. http://www.wsg.washington.edu/oysterstew/news/nutritious.html

[15] Localfoods. How to Shuck Oysters.  HYPERLINK "http://localfoods.about.com/od/shellfishrecipes/ss/How-To-Shuck-Oysters.htm"http://localfoods.about.com/od/shellfishrecipes/ss/How-To-Shuck-Oysters.htm

[16] Seafood Health Facts. Pacific Oyster, 2013. < HYPERLINK "http://seafoodhealthfacts.org/seafood_choices/oysters.php"http://seafoodhealthfacts.org/seafood_choices/oysters.php>.