Effects of salinity on oxygen consumption and ammonia excretion rate of Sanguinolaria violacea

The influence of different salinities(16,20,24,28,32,36,40 and 44) on the oxygen consumption rate and ammonia excretion rate of 3 groups(L,M,S) of clam Sanguinolaria violacea(in size of over 50 mm,40~50 mm and less than 40 mm by mean shell length) was studied under static conditions in the lab.It showed that the oxygen consumption rates of L,M and S groups were 1.11,1.25 and 1.57 mg/(g·h),and ammonia excretion rates were 62.34,83.89 and 104.68 μg/(g·h),respectively.From salinity 16 to 36 both oxygen consumption rate and ammonia excretion rate increased significantly with the increasing salinity(p0.01),reached a maximum at salinity 36 and then decreased rapidly with increasing salinity.It suggested that S.violacea can,within certain salinity range,regulate physiological metabolism to cope with hyposaline or hyperhaline conditions.During acclimation the highest cumulative mortality(55%) was observed at salinity 44,which suggest salinity 44 may be the upper salinity limit for the survival of S.violacea.Regression analysis showed that,under salinity from 16 to 36,the relation between oxygen consumption rate,ammonia excretion rate and dry tissue weight can be fixed by power correlation function.