Tolerance of the bivalve Trapezium liratum (Reeve, 1843) to decrease in salinity

抄録

Laboratory experiments were conducted to examine how the bivalve Trapezium liratum, originating from a population in the Ariake Sea, responds to decreases in salinity in cold and warm waters. After the ambient salinity had been decreased from ≈34 psu to 0–27 psu, 90 to 96% of the specimens survived for >120 h at both 12 and 24°C. When the ambient salinity was decreased to <5 psu the specimens continued to close their valves for 140 h at both temperatures. The percentages of specimens closing their valves, together with clearance and respiration rates, were in general lower for specimens with the ambient salinity more sharply decreased, regardless of water temperature. These results suggest that T. liratum can tolerate a rapid decrease in salinity by closing their valves to decrease water intake.