J.H.'s Fishing Wharf

The Pacific oysters were introduced from Japan. They develop first as males, and after a year start to function as females. Different names: Japanese Oyster, Myagi oyster, giant oyster, immigrant oyster, and giant Pacific oyster.

Description: The oyster has a rough shell that is very fluted and laminated. Shells are commonly whittish with purple streaks and spots. The can reach 10 inch in length.

Life cycle: The Pacific oyster are an exotic species, introduced in to west coast estuaries from Japan. Because spawning depends on a increase in water temperatures above 18 degrees celsius, it only spawns eratically in westcoast estuaries. As a result, cultured spat is applied to seed oyster beds. When spawning does happen, it occurs primerily in July and August. Eggs and larva are planktonic distributed through out the water column in estuarine waters. Latter stage larva settle out of the water column and crawl on the botom searching for suitable habitat before settling. Juveniles and adults are sedentery and are found in lower intertidal regions of estuaries. Oysters favor firm bottoms, and commonly attach to rocks, debris or other oyster shells. However, they can also be found on mud or mudsand bottoms.

Range: In North-America, Pacific oysters are found from South east Alaska to Baja California. It is cultivated primarily in oyster farms in sheltered coastal estuaries; although, wild beds exist in Washington and British Columbia. Habitat and ecology: Pacific oysters are a very valuable estuarine species which is threatned by pollution in its enviroment because it concentrates contaminants. Presently, many estuarine zones are completely closed to oyster culture and harvest because of bacterial and chemical contamintion assosiated with town centers, marinas, and sewege out-falls. In reality, on any given day in the US, one 3rd of all shellfish beds are closed due to contamination. Oysters face many threats as well. Anti-fouling paints containing coper can change the growth of oysters as well as cause the shell to thicken and oxygen consunption to heighten. The high sulfite content discharges by pulp mills in the Pacific Northwest are known to reduce survival and growth of oysters. In addition, siltation and turbidity resulting from loging and on shore development can cause early larva mortality. Dreging of estuaries has also severely restricted the zones available for succesful production.

Economics: Introduced in the early 1900s from Japan, Pacific oyster swiftly grabbed a footing in North America's growing aquaculture industry. In reality, the Pacific oyster is Washington's most valuable shelfish resource. Importent spawning beds is located in Puget Sound, Hood Canal, Grays Harbor, Tilamook Bay, Coos Bay and Morro Bay.