Information About

Ostreidae




  Name True Oysters
  Regnum Animal ia
  Phylum Mollusca
  Classis Bivalvia
  Ordo Ostreoida
  Familia '''Ostreidae'''
  Subdivision Ranks Genera


The members of the Family Ostreidae are the '''true oysters''', and include all the Species that are commonly eaten under the title " Oyster ". They do not include the Pearl Oyster s; these species are only distantly related to the true oysters, since although they are also Bivalve s, they are members of the family Pteriidae , in the order Pterioida .

Like Scallop s (family Pectinidae ), true oysters have a central Adductor Muscle , which means that the shell has a characteristic central scar, marking its point of attachment. Oysters have a larger adductor muscle than scallops. Their shell shape tends to be irregular as a result of attaching to other objects.

Members of genus ''Ostrea'' generally live continually immersed in sea water, brood their fertilized eggs for various proportions of the period from fertilization to hatching and are quite flat with roundish shells. They differ from most bivalves by having shells completely comprised of Calcite but with internal muscle scars of Aragonitic composition. They do best in water with a not too thick concentration of Phytoplankton .

Members of genera ''Saccostrea'' and ''Crassostrea'' generally live in the Intertidal Zone , broadcast sperm and eggs into the sea and can thrive in water which is very rich in phytoplankton. One of the most commonly cultivated oysters is ''Saccostrea gigas'', the Japanese Oyster , which is ideally suited for Oyster Cultivation In Seawater Ponds .

Both Oviparous (egg bearing) and Larviparous (larvae bearing) species are known within the Ostreidae. Both types are Hermaphrodite s. However, the larviparous species (which include the Edible Oyster ''Ostreia edulis'') show a pattern of alternating sex within each individual, whereas the oviparous species (such as the Eastern Oyster ''Crassostrea virginica'') are simultaneous hermaphrodites producing either female or male Gamete s according to circumstances.