Ostrea lurida

O. lurida has been found in archaeological excavations along the Central California coast of the Pacific Ocean, demonstrating that it was a marine species exploited by the Native American Chumash people.

Unlike most bivalves, oysters do not have a foot in adulthood; they also lack an anterior adductor muscle and do not secrete byssal threads, like mussels do.

Olympia oysters are suspension feeders, meaning they filter their surrounding water and screen out the phytoplankton they feed on.

Olympia oysters filter between 9 and 12 quarts of water each day, but is highly dependent on environmental conditions.

Their habitats must have water depths of 0–71 meters, ranging in temperatures of 6-20 degrees Celsius, with a salinity above 25 ppt.

The Olympia oyster spawns between the months of May and August, when the water reaches temperatures above 14 degrees Celsius.

The female's eggs are fertilized in the mantle cavity (brooding chamber) when spermatozoa are filtered into her gill slits from the surrounding water.

They then migrate to hard surfaces (usually old oyster shells) where they attach by secreting a glue-like substance from their byssus gland.

These have worked to put a stop to the pollution from mills,[clarification needed] and to create restrictions to prevent over-harvesting.

Highway construction and over-harvesting has also affected their substrate by creating an abundance of silt that smothers the oysters.

They are also affected by a parasitic red worm, the Japanese oyster drill, the slipper shell (which competes for space and food), and shrimp.

Species restoration projects for the Olympia oyster funded by the US Government are active in Puget Sound and San Francisco Bay.

[11] Along the estuarine shores of the Santa Barbara Channel region, these oysters were harvested by Native peoples at least 8200 years ago, and probably even earlier.

Olympia oysters and shucking knife for scale