Description
The flat oyster is oval, almost circular shaped. The shell is almost flat on one
side and the other side is deeply cupped. The flat side is usually attached to
hard substrata. The shell has circular radiating ridges on the outside, the
inside is smooth. The oysters reproduce between May and August, by releasing
larvae that will live pelagic for about two weeks. In the sixties this species
almost became extinct, after a disease and a cold winter. Because oyster
were being cultivated and had an important commercial value, it was decided to
import Crassostrea gigas until the native flat oyster had recovered. Currently
Crassostrea gigas has removed the flat oyster almost completly in Zeeland.
Size
About 150 mm in diameter.
Colour
The outside is grey-brown to blue-brown. The inside is white to grey-white.
Habitat
From the shallows up to a depth of 50 metres.
Distribution
North Eastern Atlantic from Norway till the Mediterranean and Black sea.