[International trade in bivalve mollusks and the current situation in France and in Europe].

Over the last century and a half, trade in shellfish has introduced into france four new species intended for aquaculture, as follows: -the Portuguese oyster (Crassostrea angulata) -the American clam (Mercenaria mercenaria) -the Pacific oyster (C. gigas) -the Manila clam (Ruditapes philippinarum). The development of hatcheries and air transport facilities has led to increased trade in these species among the countries of the European Union (France, Ireland, Italy, the Netherlands, Portugal, Spain and the United Kingdom); they are also imported from other countries (Morocco, Tunisia and Turkey). The species involved in this trade are the Pacific oyster, that flat oyster (Ostrea edulis), the Manila clam, the calico clam (R. decussatus) and the scallop (Pecten maximus). The reasons for such trade are economic (as markets and consumption habits differ from one country to another) and ecological (as areas suited to the growth of a species are not always those where natural reproduction is possible). Numerous problems still confront the economic participants, particularly the harmonisation of controls, the fair evaluation of disease risks and the adaptation of administrative procedures to biological constraints.