Diversification de la production conchylicole. Approche d'une stratégie d'élevage de la palourde japonaise (Ruditapes philippinarum) dans la région de la baie de Bourgneuf

If clam growth is no longer an issue during the pre-growth phase in the Bourgneuf bay region, the two year growth phase shows several problems: in the south bay area, the growth of Ruditapes phi¿lippinarum clams is inconsistent and depends on oyster and mussel stocks. In fattening ponds raising standards only allow a 500g/m final biomass. This forces clam farmers to own large areas, which are currently hardly available in this region. The alternative would consist in fractioning the growth phase into two steps: half raising in tidal zones (half buried pots at 2000/ra) or in fattening ponds, under extensive conditions (200/m) or intensive (1000/m) by adding phytoplankton. Winter stocking, for all cases in fattening ponds, would prevent major stress in tidal zones. The second growth step currently done in one year, without protection in fattening ponds (50/m) or in tidal zones (250/m) remains uncertain until stocks are regulated in the Bourgneuf bay and potential exploitation improvements are made in salt marshes. This ultimate phase will be the object of studies, notably concerning potential intensive cultivation in fattening ponds, through phytoplankton production using underground seawater.