![]() ![]() This species is very fecund, with females releasing about 50–200 million eggs in regular intervals (with a rate at 5–10 times a minute) in a single spawning. Spawning in the Pacific oyster occurs at 20 ☌. In habitats with a high food supply, the sex ratio in the adult population tends to favour females, and areas with low food abundances tend to have a larger proportion of male adults. Protandry is favoured in areas of high food abundance and protogyny occurs in areas of low food abundance. In certain environmental conditions, one sex is favoured over the other. Their sex can be determined by examining the gonads, and it can change from year to year, normally during the winter. The Pacific oyster has separate sexes, but hermaphrodites sometimes do exist. The Pacific oyster is also a very temperature tolerant species, as it can withstand a range from −1.8 to 35 ☌. The optimum salinity for Pacific oysters is between 20 and 35 parts per thousand (ppt), and they can tolerate salinities as high as 38 ppt at this level, however, reproduction is unlikely to occur. Larvae often settle on the shell of adults, and great masses of oysters can grow together to form oyster reefs. The Pacific oyster can also be found on the shells of other animals. They prefer to attach to hard or rocky surfaces in shallow or sheltered waters up to 40 m deep, but have been known to attach to muddy or sandy areas when the preferred habitat is scarce. gigas is an estuarine species, but can also be found in intertidal and subtidal zones. ![]() Mature specimens can vary from 80 to 400 mm long. Shell colour is variable, usually pale white or off-white. The two valves of the shell are slightly different in size and shape, the right valve being moderately concave. Its large, rounded, radial folds are often extremely rough and sharp. gigas varies widely with the environment where it is attached. It was previously placed in the genus Crassostrea from the Latin crass meaning "thick", ostrea meaning "oyster", and Crassostrea gigas is considered by part of the scientific community to be the proper denomination as an accepted alternative in WoRMS, Description The genus Magallana is named for the Portuguese explorer Ferdinand Magellan and its specific epithet gígās is from the Greek for "giant". 5.5.5 Competition with other uses of the seashore. ![]()
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