Pacific oyster
From Wikipedia, the free encyclopedia
| Pacific oyster | |
|---|---|
 |
|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Order: | Ostreoida |
| Family: | Ostreidae |
| Genus: | Crassostrea |
| Species: | C. gigas |
| Binomial name | |
| Crassostrea gigas Thunberg, 1793 |
|
The Pacific oyster or Japanese Oyster, Crassostrea gigas, is an oyster native to the Pacific coast of Asia. It has become an introduced species in North America, Australia, Europe, and New Zealand.
Contents |
[edit] Etymology
The species name comes from the Greek gígās meaning giant.[1]
[edit] Description
The shell of Crassostrea gigas varies widely with the environment where it is attached. There are large rounded radial folds that are often extremely rough and sharp. The two valves of the shell are slightly different in size and shape, the right valve being moderately concave. Shell color is variable and usually pale white or off-white. Mature specimens can be from 80 mm all the way up to 400 mm long.
[edit] Ecology
Crassostrea gigas can be found in intertidal and subtidal zones. They prefer to attach to hard or rocky surfaces in shallow or sheltered waters but have been known to attach to muddy or sandy areas when the preferred habitat is scarce. They can also be found on the shells of other animals. Larvae often settle on the shells of adults, and great masses of oysters can grow together to form oyster reefs.
[edit] Life cycle
Pacific oysters need a temperature of above 20° Celsius to reproduce. The larvae are planktonic and spend several weeks in this phase. Then after that time, once an acceptable location has been found the oyster drops out of the plankton and attaches itself to its chosen surface, at which point it is known as "spat". It spends the first year of its attached life as a male, before eventually becoming female. Unharvested oysters can live up to 30 years.
[edit] Introductions
Crassostrea gigas has been introduced from its native home to all over the world, ranging from North America to Australia and Europe. It has become an important commercial harvest in many of these places, and is the number one shellfish resource in Washington State. However, the Pacific oyster is considered by some to be an invasive species where it is out-competing native species, such as the Olympia oyster in Puget Sound, Washington, and the Wadden Sea, where it is out competing native shellfish such as the blue mussel, Mytilus edulis.
[edit] External links
- Crassostrea gigas, Food and Agriculture Organization of the United Nations
- Pacific oyster facts, Pacific States Marine Fisheries Commission
- Pacific oyster, United States National Oceanic and Atmospheric Administration
- http://findarticles.com/p/articles/mi_m0QPU/is_2_24/ai_n15384489
- http://www.stefannehring.de/downloads/142_Nehring-2003_Aliens-17_pacific-oyster.pdf
[edit] References
- ^ Definition of giga at dictionary.com.
