Scientists at the Slough National Estuarine Research Reserve are raising millions of native Olympia oysters in the South Slough estuary in an experiment to learn whether Olympia oysters, the Pacific Northwest's original oysters, can thrive here once again.

Olympia oysters (Ostrea lurida) are smaller than Pacific oysters, which are raised commercially all along the West Coast. Pacific oysters (Crassostrea gigas) with their ragged, rough-edged shells that grow to about the size of an adult's hand, are a familiar sight in restaurants and at seafood counters.

Olympia oysters are small by comparison. Adults may grow to about 2-3 inches (50-75 millimeters). Their shells have razor-sharp edges. They once were found from Puget Sound to Baja, California, but Olympia oysters are extinct throughout much of their former waters. Urban development, water pollution, and pulp mill discharges contributed to their demise in the early 1900s, but a few hardy populations still linger in isolated bays, including the Coos estuary.