Intensive culture of the Manila clam (Ruditapes philippinarum) in marine ponds. The impact of rearing densities and feeding levels on growth rates and yields.
Manila clam reared from 28 to 35 mm in clay bottomed raceways at 100, 200 or 300/m2 were fed on batch cultured Skeletonema costatum 34.0 and 68µ g/litre of chlorophyll a. Best final sizes were obtained in the vicinity of the inflow with a density of 100 individuals/m2. However it was a density of 300 individuals/m2 which appeared from the following results to be the optimal choice for intensive rearing: the survival rate was 84%, final biomass was 4 kg/m2 and the food chain efficiency was 0.16. Production was 10 times higher than that which has usually been obtained in these marine ponds, by means of extensive culture.