Consistent individual differences(CIDs)in phenotypes,such as morphology,physiology and behaviour,are a surprisingly widespread phenomenon in most taxa of the animals.CIDs are individual differences in phenotype that are maintained over time(e.g.as measured by repeatability)and across contexts.Many studies showed that a potential linkage between standard metabolic rate(SMR)and other physiological traits(active metabolic rate and aerobic metabolic scope)exists among different taxa of the animals.To examine the effects of starvation on the intraspecific variation and repeatability of locomotion metabolism in a carnivorous fish,the juvenile southern catfish(Silurus meridionalis Chen)which is distributed widely in the Changjiang River and other water areas,was selected as the experimental fish.The resting metabolic rate(MO_2rest)and active metabolic rate(MO_2active)of both the starvation group[(12.15±0.14)g,n=29,starved for two weeks]and control group[(12.00±0.23)g,n=28,fed with 4%-5% body weight rice field eel meal every other day]were determined in trial Ⅰ(before starvation)and trial Ⅱ(after starvation)at(25±0.5)℃.Additionally,the aerobic metabolic scope(AMS=MO_2active-MO_2rest),cost of transports(COT)and optimal swimming speed(Uopt)were also calculated during the course of the experiment to evaluate the adaptive strategy of locomotive metabolism in this fish species during food fluctuation.The results of our study showed the MO_2rest,MO_2active and AMS of the starvation group decreased significantly by 8.6%,36.3和44.1%,respectively,compared to trial Ⅰ,whereas the MO_2rest of the control group increased by 25.9% and its MO_2active did not change during the course of experiment.This unparalleled change resulted in a 12.6% decrease in AMS in the control group in trial Ⅱ.The coefficient of variance(CV)of the MO_2rest in the starvation group decreased while CV of the MO_2active and AMS increased in the same group.However,the corresponding index of the control group changed in a negative direction.The repeatability percentages of the MO_2rest,MO_2active and AMS in the starvation group were all lower than those in the control group.The slope of linear regression equation for correlation between locomotor oxygen consumption rate(MO₂)and swimming velocity in the starvation group did not change between two trials while the intercept of linear equation reduced profoundly.However,both the slope and intercept did not change in the control group between two trials.Starvation triggered a significant reduction in the repeatability in the locomotor MO₂ in the S.meridionalis.The COT_min and Uopt reduced significantly by 25% and 11.3% in the starvation group,respectively.However,the control group showed a smaller decrease in the COT_min and Uopt which reduced by 8% and 4.8%,respectively,when compared to the starvation group.Our study suggested that the juvenile S.meridionalis not only exhibited the significant repeatability in MO_2active,AMS and locomotor MO₂ with the exception of MO_2rest,but also decreased the optimal swimming speed and hence improved the swimming efficiency when this fish species was facing the low food availability conditions.Integrative regulation in swimming metabolic strategy in the southern catfish may be an adaptive consequence in a fluctuating food resources environment,and may result in an increase of survival for this fish species.