Abstract
Effect of low salinity on ventilation volume was examined in the black-lip pearl oyster Pinctada margaritifera and the pearl oyster Pinctada fucata martensii with the direct measurement method of ventilation volume. The ventilation volumes of the black-lip pearl oyster at 20°C and 26°C declined with decrease in salinity, and the ventilations stopped at 26.0-26.5 psu. In the pearl oyster at at 20°C and 28°C, the ventilation volumes in 30 psu were the same as those in 35 psu. When the salinity decreased under 30 psu, the ventilation volumes declined. And the ventilations stopped at 21.7-22.2 psu.
