European flat oyster
(Ostrea edulis)

Footage: Peter van Rodijnen / onderwaterbeelden.nl

Native Oyster

The European flat oyster / Native Oyster Ostrea edulis represents a key species with important ecological functions and ecosystem services in the marine ecosystem. As reef structures, oyster beds provide food and habitat for numerous species and, in addition, serve as nursery grounds for many fish species. Therefore, oyster beds are considered to be biodiversity hot spots. By filtering large volumes of water, oysters also improve water quality on local scales. A single oyster can filter up to 240 litres of sea water per day – if done by millions of oysters, who populated the North Sea in the past, it would be an incredible extensive eco-service.

Profile of the European flat oyster

Name:
European flat oyster
Scientific name:
Ostrea edulis
French:
Huître plâte
German:
Europäische Auster
Size:
up to approx.15 cm
Age:
up to 30 years; sexually mature at 3-4 years
Appearance:
Shape roundish to oval. Left / lower valve convex, right / upper valve almost flat and fitting inside the left valve to close it. The genus Ostrea ´flat oysters` takes its name from its shape.
Habitat:
Deep marine habitats at 30-50 metres below the surface; also found just below the low water line. Preferentially colonises substrate composed of oyster shells.
Status:
Now very rare in Europe due to massive overfishing; included in the OSPAR List of Threatened and/or Declining Species and Habitats for the North-East Atlantic.
Ecosystem services:
Enhancement of biodiversity; provides food, protection and habitat for numerous species; improvement of water quality; reduction of toxic algal blooms; mediation of benthic-pelagic coupling; binding of loose sediment; coastal protection.