The Ostreidae, or true oysters, are the food oysters of commerce world-wide. While all oysters are capable of secreting the nacre that forms pearls, those of the Ostreidae family are inconsequential (gemstone pearls are commercially harvested from oysters of the more distantly related Pteriidae family).

 

Despite obvious shell differences, oysters and scallops (Pectinidae) are related in that both molluscs have a central adductor muscle with the characteristic central shell scar. In the Ostreidae, the central adductor muscle is  much larger and not bounded by ridges. Radial ribbing if present subdivides and is more irregular, as is also the shell shape, which beomes distorted by cementation to other objects. If present, denticles or teeth along the shell margin are characteristic of individual species.

 

Reproductive behavior in the oyster is remarkable in that both oviparous (egg   bearing) and larviparous (larvae bearing) species are found. The larviparous species, of which Ostreia edulis is typical, show a life history of alternating sex changes in the same individual, whereas the oviparous species, e.g., O. virginica, or O. gigas, are essentially hermaphroditic and may produce either predominantly male or predominantly female gametes depending on environmental temperature and nutrient availability (Morton, 1960).

Classification

Class: Bivalvia

Subclass: Pteriomorphia

Order: Ostreina

Superfamily: Ostreacea

Family: Ostreidae

 

Major Genera

• Genus: Crassostrea
• Genus: Hyotissa
• Genus: Lopha
• Genus: Ostrea
• Genus: Saccostrea

Ostrea edulis (Linnaeus, 1758)
Common European Oyster

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