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Not all individual oysters produce pearls naturally.
In fact, in a harvest of two and a half tons of oysters, only three to four oysters produce what commercial buyers consider to be absolute perfect pearls.
At the same time, two kidneys, located on the underside of the muscle, remove waste products from the blood.
Their nervous system includes two pairs of nerve cords and three pairs of ganglia.
Crassostrea and Saccostrea live mainly in the intertidal zone, while Ostrea is subtidal.
In three to seven years, the oyster can produce a perfect pearl.
The larvae develop in about six hours and exist suspended in the water column as veliger larvae for two to three weeks before settling on a bed and maturing to sexual adulthood within a year.
As a keystone species, oysters provide habitat for many marine species.
While some oysters have two sexes (European oyster and Olympia oyster), their reproductive organs contain both eggs and sperm.
Because of this, it is technically possible for an oyster to fertilize its own eggs.