The official website of the Elkhorn Slough Foundation and Elkhorn Slough National Estuarine Research Reserve
Elkhorn Slough Invertebrates: Olympia Oyster

Scientific Name:
Ostrea lurida


Found at the Slough:

Did you know...
Native oyster reefs improve water quality by their filter feeding activity, and provide habitat that increases estuarine fish and invertebrate diversity.

The Olympia Oyster is the native oyster to our area. They have lived in the Elkhorn Slough estuary for the last 10,000 years. Humans have been consuming these sweet delicacies for more than 7,000 years.

Formerly abundant, they are now rare with an estimate of only 5,000 live oysters remaining in the Elkhorn Slough estuary - a tiny fraction of historical abundance. Causes of their decline include overharvesting, poor water quality, habitat loss, disease, and habitat alteration.

They are found along the Pacific Coast from Washington to Baja. Here at the Slough they are found around the Reserve and in the upper Slough near Kirby Park. 

They spend their lives attached to hard substrates (such as mussel shells,  clam shells, or adult oyster shells) in the mudflats and feed on tiny particles in the water.

Olympia Oyster, Ostrea lurida
Olympia oyster

Researchers are tracking growth rate, recruitment, survival, and adult density in various habitats in the Slough. In the summer of 2009, Elkhorn Slough volunteers, interns, and staff implemented methods that have been successful on the East Coast – oyster reefs made of clam shells. Large clam shells were collected in the lower estuary to use in the mid-upper estuary (Parsons, Azevedo). Biodegradable mesh-type tubes were filled with the collected clam shells. The tubes were secured with bamboo stakes and placed at different sites and elevations. After only seven months, population increase was evident.
Read more about native oyster research in the Slough...


Recent press about Oyster Research here at Elkhorn Slough:

Further reading:


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This site is maintained by the Elkhorn Slough Foundation in partnership with the Elkhorn Slough National Estuarine Research Reserve