Use of effluent water from fish-ponds as a food source for the Pacific oyster, Crassostrea gigas Thunberg

Abstract. Growth rates, condition indices and diet composition of the Japanese oyster, Crassostrea gigas Thunberg, were studied in two types of ponds which form part of a fish-bivalve integrated culture system. Although abiotic parameters (e.g. temperature, salinity, pH, ammonia, particulate inorganic matter) were similar in the two pond types, oysters supplied with water from a sedimentation pond grew significantly faster and showed better condition indices than the oysters supplied with water from the PVC-lined ponds. It is suggested that the main reasons for the better performance of the oysters supplied with water from sedimentation pond water are: higher algal diversity, additional nutritious Food consisting of attached benthic diatoms and stable algal concentration.