Abstract
Changes of the ventilation volume and the amount of oxygen uptake with feeding Chaetoceros gracilis were examined in the rock-oyster Crassostrea nippona. At a density of 20,000 cells/ml, the ventilation volumes at 17, 20, 25 and 28°C increased to 9.2, 8.1, 6.6 and 3.8 times (8.60, 10.88, 13.00 and 9.30 l/min/kgWW, per wet weight of soft part of body) those without feeding (0.93, 1.35, 1.98 and 2.46 l/min/kgWW), respectively. The amount of oxygen uptakes with feeding at 17 and 28°C were 0.580 and 0.910 ml/min/kgWW and were about equivalent to those, 494 and 0.880 ml/min/kgWW, without feeding, respectively. However, the amount of oxygen uptakes increased to 1.6 and 1.5 times (0.769 and 1.040 ml/min/kgWW) those without feeding (0.485 and 0.710 ml/min/kgWW) at 20 and 25°C, respectively. These results suggested that the Rock-oyster increased the ventilation volume without a marked increase in the amount of oxygen uptake with feeding.
