Summary Description

Crassostrea virginica is generally known as the common oyster. The shell exterior is dirty white to grey or brown in colour with a thick, flattened, and highly variable in shape (Puglisi 2008; FAO 2011). It is usually 10 to 15 cm long when the oyster is 3 to 5 years old and it continues to grow, primarily in thickness, over the lifespan of the oyster (Stanley and Sellers 1986).

The left valve tends to be thicker, more deeply cupped and heavier than the right valve. When the valves are fully closed there is no remaining gap (Stanley and Sellers 1986). The oyster attaches itself to the substrate by its left valve. The shape of the shell can vary and the thickness and strength of the shell is harder when the oyster is on harder substrates.

The distribution of Crassostrea virginica is determined by settlement of the larvae and subsequent development to the adult form. Adult oysters are sessile. Single oysters from hard substrates are rounded and sculpted with radial folds, whereas those from soft substrates or reefs are more slender and sparsely sculpted with radial folds (Stanley and Sellers 1986).

Crassostrea virginica is an important aquaculture species in North America (FAO 2011).