中文摘要：

标准代谢率（Standard metabolic rate,SMR）通常被作为鱼类维持基础代谢的指标,日常代谢率（Routine metabolic rate,RMR）则反映了鱼类在日常自发游泳非受限制状态下的代谢水平,两者大量被用于衡量鱼类种内个体差异研究。以鲢（Hypophthalmichthys molitrix）幼鱼为研究对象,在环形水槽（微流速）及矩形呼吸室（静水）中测定了水温20℃条件下的耗氧率,分别作为RMR和SMR1的指标,并用递增流速法得到耗氧率随流速变化的曲线,将不同流速下的耗氧率变化拟合得到指数曲线（y=a10^bU）并将曲线外推至U=0与Y轴相交,截距可认为是速度为0时的耗氧率,即为标准代谢率SMR2,比较3种方法得到的耗氧率。结果表明：（1）自然水温条件下,SMR1为（401±55.59）mg/（h·kg）,变化范围为325～484 mg/（h·kg）,个体差异近0.7倍;而RMR为（594.17±126.21）mg/（h·kg）,变化范围434～770 mg/（h·kg）,个体差异近0.6倍。实验鱼的SMR1与RMR呈显著正相关,随着SMR1的增大,RMR逐渐升高,RMR约为SMR1的1.5倍;（2）静水中得到的SMR1为（401±55.59）mg/（h·kg）和利用活动代谢率外推得到的SMR2为（418±66.24）mg/（h·kg）,2种不同方法得到的SMR大致为1∶1,相差不显著,且2种方法得到的SMR值均显著小于RMR的值（P〈0.05）。研究有助于探究鲢幼鱼SMR和RMR之间的关系及不同测试方法对SMR的影响,对水生态保护及水产养殖具有指导意义。

英文摘要：

The standard metabolic rate（SMR） is the oxygen consumption of a fish species under static conditions：the metabolic rate of fish at rest.The routine metabolic rate（RMR） is the oxygen consumption of fish at a minimal flow.Both parameters are used as the metabolic baseline in tests of swimming capability,but the relationship between SMR and RMR is unclear and further study is needed.In this investigation,the oxygen consumption rate（MO2） of juvenile silver carp was measured at 20℃ in two types of respirometer.The RMR was measured in a swimming respirometer with low flow velocity,sufficient for adequate mixing but not high enough to induce swimming.SMR was obtained using two methods：SMR1 was measured in a rectangular resting（static） respirometer and SMR2 was calculated from a power function relating MO2 and swimming speed（U）,using data from a stepped velocity test.Juvenile silver carp of body length 8-12 cm and body mass 8-16 g were acclimated for two weeks before testing and each test was carried out 10 times using a different fish in each trial.A single fish was placed in the swimming respirometer（1 800 mm×400 mm×600 mm） with velocity adjusted to 0.5 BL/s.The dissolved oxygen was measured every 30 min for 5 hours.After one hour,the fish was placed in the static respirometer,acclimated for 2 h,and the dissolved oxygen was again measured every 30 min for 5 hours.The oxygen consumption of juvenile silver carps was also measured in the swimming respirometer during a stepped velocity test.A test fish was placed in the swimming chamber for 2 h at a velocity of 0.5 BL/s.The velocity was then increased in 0.5 BL/s increments at 30 min intervals until the fish was fatigued.The dissolved oxygen was measured every 5 min.The data for MO2 and U was fitted to a power function（MO2=a10^bU） and SMR2 was obtained by calculating MO2 at U=0 BL/s.Values for SMR1 and SMR2were compared and the relationship between RMR and SMR was analyzed.Results show：（1） SMR1[401±55.59 mg/（h·kg） ] was sligh