lurida populations are much more stable now due to the action of conservancy associations and new laws. These have worked to put a stop to the pollution from mills, and to create restrictions to prevent over-harvesting. During the harvesting seasons, people with permits now have to shuck their oysters on the beach to keep from depleting the oyster beds that the spat grow on. There is still a market for Olympia oysters, in which farms commercially grow and sell them. This helps prevent the depletion of the native wild Ostrea lurida. Threats The once thriving Olympia oyster has been endangered by pollution from mills and outboard motors. Highway construction and over-harvesting has also affected their substrate by creating an abundance of silt that smothers the oysters. Over-harvesting also takes away the old shells that spat need to grow on. The oysters are preyed upon by animals such as sea ducks and rock crabs (Cancer productus). They are also affected by a parasitic red worm (which lives in their anus), the Japanese oyster drill, the slipper shell (which competes for space and food), and shrimp. The ghost shrimp and blue shrimp stir up sediment that can smother the oysters. This species of oyster nearly disappeared from San Francisco Bay following overharvest during the California Gold Rush (1848-50s) and massive silting from hydraulic mining in California's Sierra Nevada (1850s-1880s). California's most valuable fishery from the 1880s-1910s was based on imported Atlantic oysters, not the absent native. But in the 1990s, O. lurida once again appeared in San Francisco Bay near the Chevron Richmond Refinery in Richmond, California. Restoration efforts Species restoration projects for the Olympia oyster funded by the US Government are active in Puget Sound and San Francisco Bay. An active restoration project is taking place in Liberty Bay, Washington. This Puget Sound location is the home of an old and new Olympia oyster population. Intertidal areas with native oyster populations or evidence of past populations are strong candidates for re-introduction. The re-establishment of the population is currently threatened by the invasive Japanese oyster drill Ocenebra inornata. This species preys on the oysters by drilling a hole between the two valves and digesting the oyster's tissues. O. inorata is a threat to the oyster especially in areas with low populations of the mussel Mytilus. The Nature Conservancy of Oregon also has an ongoing restoration project at Netarts Bay, Oregon. Use by