Effects of temperature and salinity on oxygen consumption rate and ammonia excretion rate of clam Estellarca olivacea

Clam Estellarca olivacea is distributed in Philippines,Japan and China.In this study,four levels of water temperatures(15℃,20℃,25℃ and 30℃) and five levels of water salinities(16,21,26,31 and 36) were designed to determine the relationship between oxygen consumption(O) and ammonia respiration(N) rate of E.olivacea,and the effects of temperature and salinity on the relationship under controlled laboratory conditions.The dry weight of soft tissue of E.olivacea was(0.122±0.025)g(n=48).The experimental results were as follows:the respiration and excretion of clam E.olivacea were affected by temperature and salinity significantly(P0.05).Under the controlled conditions of ambient temperature 15-30℃,both oxygen consumption rate and ammonia excretion rate increased with the increase of temperature.Oxygen consumption rate ranged from 0.37 to 0.65mg/(g·h) with a mean value of 0.51mg/(g·h),and ammonia excretion rate ranged from 1.74 to 3.15μmol/(g·h) with a mean value of 2.32μmol/(g·h).The value of atomic ratio of O to N ranged from 12.99 to 15.43 under the controlled conditions of ambient temperature 15-30℃.Under salinity 16-36,oxygen consumption rate and ammonia excretion rate decreased with the increase of salinity from 16 to 26,then increased with salinity from 26 to 36.Oxygen consumption rate ranged from 0.43 to 0.60mg/(g·h) with a mean value of 0.52mg/(g·h),and ammonia excretion rate ranged from 1.75 to 3.26μmol/(g·h) with a mean value of 2.45μmol/(g·h).The experiment provided some fundamental information for the further study on the physiology and ecology of clam E.olivacea,and played an important role for its wide culture.