In 1999, the world aquaculture production of molluscs was estimated at 9.4 million tonnes which represents approximately a 23% contribution to the global aquaculture production. Aquaculture of molluscs has been growing at an average annual rate of 11% over the past decades, although some activities - such as aquaculture of pectens or abalones - were growing even more rapidly. In many countries, there is a significant mollusc aquaculture, traditionally based on wild stocks. However, these natural populations frequently do not fulfil market demand, because of low value of the product, over-fishing of the resource and/or mass mortality outbreaks caused by diseases. A frequent answer to this situation has been the introduction of new stocks or new species in these areas (Grizel, 1996). Furthermore, species diversification for aquaculture, as well as hatchery production improvements do increase the demand for movements and transfers of live molluscs.