Some types of pearl oysters are harvested for the pearl produced within the mantle. True oysters are members of the family How long does it take to cook mussels. Almost all shell-bearing mollusks can secrete pearls, yet most are not very valuable.
Pearls can form in both saltwater and freshwater environments. The largest pearl-bearing oyster is the marine Pinctada maxima, which is roughly the size of a dinner plate. Not all individual oysters produce pearls naturally. In nature, pearl oysters produce pearls by covering a minute invasive object with nacre. Over the years, the irritating object is covered with enough layers of nacre to become a pearl. The many different types, colours and shapes of pearls depend on the natural pigment of the nacre, and the shape of the original irritant.
Pearl farmers can culture a pearl by placing a nucleus, usually a piece of polished mussel shell, inside the oyster. In three to seven years, the oyster can produce a perfect pearl. Since the beginning of the 20th century, when several researchers discovered how to produce artificial pearls, the cultured pearl market has far outgrown the natural pearl market. Pilgrim oyster, another term for a scallop, in reference to the scallop shell of St. In the Philippines, a local thorny oyster species known as Tikod amo is a favorite seafood source in the southern part of the country.
Because of its good flavor, it commands high prices. In addition to their gills, oysters can exchange gases across their mantles, which are lined with many small, thin-walled blood vessels. Because of this, it is technically possible for an oyster to fertilize its own eggs. The gonads surround the digestive organs, and are made up of sex cells, branching tubules, and connective tissue.