Olympia Oyster

Ostrea lurida or Ostrea conchaphila

SARA Status
No Status
NS
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

SARA Status

  • No Status NS
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX
COSEWIC Status
Not at Risk
NR
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

COSEWIC Status

  • Not at Risk NR
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX

At a glance

The Olympia oyster, regaled as a world-class culinary delicacy, is the only oyster native to the west coast of North America. This small oyster was a staple diet for some Indigenous coastal tribes for thousands of years, but it was so over-fished in the 19th and early 20th centuries that it was largely decimated. Although not harvested in large numbers since then, it hasn’t replenished itself. Experts don’t know why, but suspect human factors might be to blame.

About the Olympia oyster

For thousands of years the Olympia oyster was the only oyster known to the British Columbia west coast. It leads a seemingly inert life when not feeding, finding a home-base, or reproducing. But inside its shell, this quiet oyster has an active sex life. All Olympia oysters become males by age one, and then will morph between male and female, alternating each year in producing either eggs or sperm, for the rest of their 10 + year lifespan.

In Canadian waters reproduction occurs in the warmer summer months. At this time the female produces up to 300,000 eggs, which she keeps inside her shell cavity. The male then releases sperm into the surrounding water which she ingests and siphons through the eggs. About two weeks later she releases the fertilized eggs into the water, where they drift for a few weeks as larvae before settling on a hard substrate, such as a rock or even other shells.

Olympia oysters are filter feeders, siphoning water and digesting the tiny marine algae that passes through their systems. Various crabs, snails, sea stars and birds feed on the Olympia oyster.

How to recognize the Olympia oyster

Smaller than most oysters, the Olympia oyster will be at most nine centimetres in length and more likely just six centimetres. It is oval, and like all oysters, has two shells connected by a hinge. Its larger lower shell is rounded like a cup while the slightly smaller upper shell is flat – with its edges tucking inside the rounded shell. Its outer shell ranges in colour from white to dark purple while its inside shell can be white, iridescent green and purple.

Where the Olympia oyster lives

The Olympia oyster lives along the west coast of North America, between southern Alaska and down to Panama. It typically makes its home in protected saltwater coves, lagoons and estuaries (saltwater rivers) where rising and falling tides won’t disturb it. It is usually attached to submerged rocks and hard ground in shallow waters. In British Columbia the Olympia oyster is found along the Georgia Strait, the west coast of Vancouver Island, and around Queen Charlotte Strait and Sound.

Why the Olympia oyster is at risk

We don’t know how many Olympia oysters used to live off the B.C. coast, but scientists believe that the Olympia oyster population was drastically reduced by over-fishing between the early 1800s and 1930. It has not replenished itself since then, quite possibly because of pollution and disease. Other human causes, including the introduction of foreign oysters into the Olympia oyster’s habitat, could have also contributed to its decline. In Canada, this oyster is also near the northern limit of its territory, so cold ocean temperatures slow its ability to repopulate.

What’s being done

The Olympia oyster is listed under the federal Species at Risk Act (SARA) and protected under the federal Fisheries Act which prohibits destruction of fish habitat. It is also illegal to commercially harvest Olympia oysters from the wild, although they can be harvested from regulated aquaculture farms. Please refer to the Management Plan for the Olympia Oyster on the Species at Risk (SARA) Public Registry Profile for more information.

What can you do?

The Olympia oyster will only get the protection it needs if Canadians work together to reduce threats. Find out more about the Olympia oyster and be aware of human-induced threats. Do your best to reduce these threats wherever possible to better protect the Olympia oyster’s habitat. Get involved with the Habitat Stewardship Program for Species at Risk (HSP) or another conservation organization.

Background information provided by Environment Canada, April 2006.

Olympia Oyster

olympia oyster

Rick Harbo

Scientific name: Ostrea lurida
Other/Previous Names: Ostrea conchaphila
Taxonomy: Molluscs
SARA Status: Special Concern (2003)
COSEWIC Status: Special Concern (2000)
Region: British Columbia

olympia oyster

Fisheries and Oceans Canada

Did You Know?

Signature dish of the California Gold Rush
During the California Gold Rush, a meal of fried Olympia oysters and eggs became the signature dish for the men who struck gold because this was the most expensive meal of its day. The famous dish was named the “Hangtown Fry” – legend has it that a man condemned to die by hanging in 1859 asked for fried Olympia oysters, then known simply as “native western oysters” as his final meal and the name stuck. The dish continued its fame through the latter Klondike Gold Rush and is still served as a signature saloon meal in many old gold-rush towns.

To this day the Olympia oyster – now only harvested from aquaculture farms – is considered an excellent cocktail oyster, served raw or fried and always with a tangy aftertaste.

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