oyster, edible bivalve bivalve, aquatic mollusk of the class Pelecypoda ("hatchet-foot") or Bivalvia, with a laterally compressed body and a shell consisting of two valves, or movable pieces, hinged by an elastic ligament.
..... Click the link for more information. mollusk found in beds in shallow, warm waters of all oceans. The shell is made up of two valves, the upper one flat and the lower convex, with variable outlines and a rough outer surface. Since the oyster spends most of its life (except for the free-swimming larval stage) attached—having fused its valve with a sticky substance to a substratum of shells, rocks, or roots—the foot is rudimentary. In some species the sexes are separate and the eggs are laid and fertilized in the water; in others the animal is hermaphroditic and the eggs are retained with the shell. Only a small proportion of the millions of eggs laid survive. Large numbers of the free-swimming larvae, called veligers, are consumed by fish and other animals. After the oyster becomes sessile, it is victimized by oyster drills, starfish, and other enemies. Most species are too small for food, but the American, or common, oyster reaches a length of 2 to 6 in. (5–15 cm). These oysters are harvested in artificial beds on both coasts of the United States: on the Atlantic especially in the regions of the Delaware and Chesapeake bays and in the waters off Long Island, in the Gulf Coast off Louisiana, and in the Pacific off the state of Washington. Prepared beds are usually seeded with veligers or young sessile oysters called spats. In warm waters they mature in 1 1-2 years; in cooler waters the period of growth is about 4 to 5 years. They are usually transplanted several times before harvest to enhance their food supply and stimulate growth. The wing and the pearl oysters are widespread in warmer seas; there is one eastern and one western species of each in American waters. The great pearl oyster, from which the pearl pearl, hard, rounded secretion formed inside the shell of certain mollusks, used as a gem. It is secreted by the epithelial cells of the mantle, a curtain of tissue between the shell and body mass, and is deposited in successive layers around an irritating
..... Click the link for more information. is obtained, is a large (12-in./30.5-cm) tropical species. Oysters are classified in the phylum Mollusca Mollusca , taxonomic name for the one of the largest phyla of invertebrate animals (Arthropoda is the largest) comprising more than 50,000 living mollusk species and about 35,000 fossil species dating back to the Cambrian period.
..... Click the link for more information. , class Pelecypoda or bivalvia, order Filibranchia, family Ostreidae.
Any bivalve of two families, Ostreidae (true oysters) or Aviculidae (pearl oysters), found in temperate and warm coastal waters worldwide. Both valves (halves) have a rough, often dirty-gray outer surface and a smooth white inner lining (nacre). The lower valve, which affixes to a surface, is nearly flat. The smaller upper valve is convex and has rougher edges. The oyster filters its food, minute organic particles, from the water. Cultivated as food, oysters are regarded as a delicacy. Pearls are the accumulation of nacre around a piece of foreign matter.
oyster
oyster [′ȯi·stər]
..... Click the link for more information. mollusk found in beds in shallow, warm waters of all oceans. The shell is made up of two valves, the upper one flat and the lower convex, with variable outlines and a rough outer surface. Since the oyster spends most of its life (except for the free-swimming larval stage) attached—having fused its valve with a sticky substance to a substratum of shells, rocks, or roots—the foot is rudimentary. In some species the sexes are separate and the eggs are laid and fertilized in the water; in others the animal is hermaphroditic and the eggs are retained with the shell. Only a small proportion of the millions of eggs laid survive. Large numbers of the free-swimming larvae, called veligers, are consumed by fish and other animals. After the oyster becomes sessile, it is victimized by oyster drills, starfish, and other enemies. Most species are too small for food, but the American, or common, oyster reaches a length of 2 to 6 in. (5–15 cm). These oysters are harvested in artificial beds on both coasts of the United States: on the Atlantic especially in the regions of the Delaware and Chesapeake bays and in the waters off Long Island, in the Gulf Coast off Louisiana, and in the Pacific off the state of Washington. Prepared beds are usually seeded with veligers or young sessile oysters called spats. In warm waters they mature in 1 1-2 years; in cooler waters the period of growth is about 4 to 5 years. They are usually transplanted several times before harvest to enhance their food supply and stimulate growth. The wing and the pearl oysters are widespread in warmer seas; there is one eastern and one western species of each in American waters. The great pearl oyster, from which the pearl pearl, hard, rounded secretion formed inside the shell of certain mollusks, used as a gem. It is secreted by the epithelial cells of the mantle, a curtain of tissue between the shell and body mass, and is deposited in successive layers around an irritating
..... Click the link for more information. is obtained, is a large (12-in./30.5-cm) tropical species. Oysters are classified in the phylum Mollusca Mollusca , taxonomic name for the one of the largest phyla of invertebrate animals (Arthropoda is the largest) comprising more than 50,000 living mollusk species and about 35,000 fossil species dating back to the Cambrian period.
..... Click the link for more information. , class Pelecypoda or bivalvia, order Filibranchia, family Ostreidae.
oyster
)
European flat oyster (Ostrea edulis)
(credit: G. Tomsich—Photo Researchers)
oyster
1.
a. any edible marine bivalve mollusc of the genus Ostrea, having a rough irregularly shaped shell and occurring on the sea bed, mostly in coastal waters
b. (as modifier): oyster farm
2. any of various similar and related molluscs, such as the pearl oyster and the saddle oyster (Anomia ephippium)
oyster [′ȯi·stər]
(invertebrate zoology)
Any of various bivalve mollusks of the family Ostreidae; the irregular shell is closed by a single adductor muscle, the foot is small or absent, and there is no siphon.
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