Effects of body weight and temperature on oxygen consumption and ammonia excretion in clam Mactra chinensis

The oxygen consumption and ammonia excretion in clam Mactra chinensis with different dry soft part weight(0.9901 g±0.540 g,0.5244 g±0.0257 g,0.2886 g±0.0421 g)were determined under various temperature(13,18,23 ℃,and 28 ℃) and a salinity of 33 to evaluate the relationship between the oxygen consumption rate and the body size under controlled laboratory condition.It was found that the individual size,and temperature significantly affects on oxygen consumption rate and ammonia excretion rate(P0.01),an the interaction of the both showed significant effects on oxygen consumption rate(O)(P0.05).The relationship between O and dry weight of the soft tissue(W) was represented by the allometric equation O=aWb,where a ranging from 0.695 to 1.762,with mean of 1.449,and b varying from 0.446 to 0.587,with mean of 0.542.The ammonia excretion rate decreased as the increase in body size and there was a negative exponential regressive function N=a0W-b0.