The year round availability of high numbers of topquality bivalves larvae is a major problem in the field of molluscs farming. As regards monitoring of gonad ripening , recent technical developments have allowed the periods of natural spawning of male and female gametes to be extended, by manipulation of environmental parameters. Instead, as regards gamete and embryo stocking, available information is scanty and refer exclusively to cryopreservation for fish (Villani and Catena 1991) and mammals. The Ifremer Centre of Brest (France) has carried out some low-temperature preservation experiments of Pecten maximus male gametes over a period of three months, in order to evaluate their preservation in time and later use for fertilization tests