The correlations between standard metabolic rate and metabolic characteristics after exhaustive exercise, and behaviour in the juvenile crucian carp (Carassius auratus)

Consistent individual differences( CIDs) in phenotypes,such as physiology and behavior,are widespread phenomena in most animal taxa. CIDs are individual differences in phenotype that are maintained over time( e. g. as measured by repeatability) and across contexts. Many previous studies showed that there is a potential link between standard metabolic rate( SMR) and other physiological traits,and animal personality exists in a diverse array of animal taxa. The aim of this study was to investigate the relationship between the SMR and metabolic characteristics after exhaustive exercise,and behavior,as well as the individual differences in these phenotypes in the juvenile crucian carp(Carassius auratus),a widely distributed and medium-sized Cyprinid species. To fulfill our aim,the SMR of 80 fish individuals was first measured at(25. 0 + or - 0. 5) [degrees]C,after which 40 individuals out of the total were selected to serve as theexperimental fish. These 40 fish included 20 higher-SMR individuals and 20 lower-SMR individuals. Secondly,after chasing individual fish until they reached the point of exercise exhaustion within 5 min,the maximum aerobic metabolic rate(MMR),aerobic scope(AS = MMR- SMR),factorial aerobic scope(FAS = MMR/SMR),and magnitude of EPOC of each individual were examined during a 30 min period of metabolism recovery. Thirdly,the response time( RT),maximum linear speed( Umax),maximum linear acceleration speed(Amax),and distance travelled in 120 ms(S120) during a fast-start escape response were measured. Lastly,indicators of animal personality,including boldness and activity were also studied in each of the 40 individuals. This study demonstrated that the SMR of the experimental fish correlated negatively and the MMR correlated positively with AS,FAS,and the magnitude of EPOC. Individuals with high SMRs exhibited the same recovery rate as those individuals with smaller SMRs. The SMR of the experimental fish correlated negatively with Amaxbut correlated positively with RT. Neither Umaxnor S120 showed any relationship with SMR. Correlations within components of the fast-start response found that Umaxwas positively correlated with the Amaxand S120,while RT was negatively correlated with Umax,Amax,and S120,among the individual fish. Neither boldness(as indicated by latency,exposed time,and appearance frequency) nor activity( as indicated by percent time spent moving and frequency of hit wall) showed any correlation with SMR in the juvenile crucian c