Living feeds collected at each hanging depth of oyster clumps in environmental sea water of oyster farm were analyzed for the determination of copper and zinc.
The results obtained were very similar to those obtained in the former experiment with oyster. The concentration of copper and zinc in oysters cultured at Miyako Bay showed a tendency to decrease according to the hanging depth of oyster clumps, while that in the sea water inversely. The same tendency was also observed in the weight of soft part of oysters.
These results suggest that the growth pattern of cultured oysters, together with the heavy metal accumulation in food substances for oysters, is the principle factor in the characteristics of heavy metal accumulation at each oyster hanging depth.