The European flat oyster (Ostrea edulis) was once widespread but has now become so scarce in the North Sea that it no longer forms ecologically functioning reefs. Along with the demise of the flat oyster, the three-dimensional structures that provide habitat for more than 100 marine species have dis appeared. Restoration therefore focuses not only on the return of the European flat oyster itself but also on the reef and its associated biodiversity. ...read more read less