Pacific+Oyster

Phylum: Mollusca
 * Common Name: ** Pacific Oyster

**Class**: Bivalvia
 * Scientific Name: **//Crassostrea gigas//


 * Location: ** In North America, the Pacific oyster is found from Southeast Alaska to Baja California. It is cultivated primarily on oyster farms in protected coastal estuaries; however, some wild beds exist in Washington and British Columbia.


 * Size: ** Rough shell that is highly fluted and laminated. Shells are usually whitish with purple streaks and spots. Can reach 10 inches in length.


 * Habitat: ** Oysters prefer firm bottoms, and usually attach to rocks, debris or other oyster shells. However, they can also be found on mud or mud-sand bottoms. Oysters have been found attached to bricks, boats, cans, tires, bottles, crabs, and turtles, but they prefer to attach to other oysters. When a large number of oysters join together, it's called an "oyster reef".


 * Living Requirments: ** Oysters are also filter-feeders. They feed by using their gills to filter tiny food particles out of the water.


 * Life Cycle: **The Pacific oyster is an exotic species, introduced into west coast estuaries from Japan. Because spawning depends on a rise in water temperatures above eighteen degrees Celsius, it only spawns erratically in west coast estuaries. As a result, cultured "spat" is used to seed oyster beds. When spawning does occur, it occurs primarily in July and August. Eggs and larvae are planktonic distributed throughout the water column in estuarine waters. Later stage larvae settle out of the water column and crawl on the bottom searching for suitable habitat before settling. Juveniles and adults are sedentary and are found in lower inter-tidal areas of estuaries.

Threatened and Human Impact: The Pacific oyster is a highly valuable estuarine species which is threatened by pollution in its environment because it concentrates contaminants. Presently, many estuarine areas are completely closed to oyster culture and harvest because of bacterial and chemical contamination associated with urban centers, marinas, and sewage outfalls.
 * Male and Female Differences: ** Females may release more than 100 million eggs during a season. Only about one percent of the fertilized eggs reach the next stage of maturity. Oysters are protandric-in the first year, they spawn as males, but as they grow larger and develop more energy reserves, they spawn as females.

**Human Impact**: After the BP oil spill Pacific Oyster are starting to become poor in harvest.


 * Interesting Facts: **
 * Pacific oysters were introduced from Japan.
 * They develop first as males, and after a year begin to function as females.
 * As filter-feeders, oysters can concentrate bacteria and viruses within their bodies.
 * Several pearls may occur in one oyster. A world record has not been established, but a Galveston Bay oyster containing 356 pearls must be a leading contender.

Look at this rocky video, you will have a shell of a good time!!! []

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 * Zookeeper's Sources: **