Etat des stocks conchylicoles normands en 2000

Crassostrea gigas and Mytilus edulis are reared in four areas along the eastern coast of Cotentin (Normandy). Every five years, a stock assessment survey, based on a stratified random sampling is carried out using aerial photographs. During September 2000, oysters bags and mussel banks random samplings have been weighed on leasing grounds and in random sampled farms in order to evaluate the overall total gross and net weights breeded (oysters 40 000 and mussels 17 000 metric tons, net weights). Age compositions of each stock in each rearing area have been computed. This last stock assessment showed that cultural regulations are less and less observed in Normandy's breeding areas. A strong increase in bag densities has been noticed since 1995. As stock levels remained stable, decreases in yields have been noticed. As a consequence of this report, farmers and Official Authorities should adopt recommendations on cultural practices in Normandy in order to improve shellfish culture management.