Intraspeciflc Differences In Standard Metabolic Rate(SMR) And Its Relationship With Locomotion And Feeding In Juvenile Common Carp (Cyprinus Carpio)

The objective of this study was to investigate the intraspecies differences instandard metabolic rate (SMR), and its potential relationship with locomotion andfeeding. Juvenile carps (Cyprinids cardio) were acclimated at25±1oC,and measuredstandard metabolic rate. Then,the specific dynamic action (SDA), spontaneousswimming behaviour,critical swimming speeding (Ucrit) and active metabolicrate(MO2active) were measured corresponding to the standard metabolic rate one by one.We hope that our study could reveal the adaptive strategies applied among individualswithin species.The results are:1. The SMR were219.36土8.93mgO2kg-1h-1,ranging from76.71to317.63mgO2kg-1h-1, the individual difference was up to4.14times.2. The average caudal fin beat frequency in10min observation period (FBF10min)increased with SMR elevation, and revealed in positive correlation (P=0.042). Ucrit(P=0.497)and active metabolic rate (P=0.317) were not related to SMR. There was asignificant positive correlation between the average caudal fin beat frequency andpercent time spent moving (PTM)(P<0.0001). The average caudal fin beat frequency in10min observation period was negatively correlated with such frequency in movementperiod (FBFmovement)(P=0.004).3. The peak metabolic rate was positively correlated with SMR (P=0.022), SDA duration(P=0.004), SDA total energy (P <0.0001), MO2active(P=0.018) and metabolic scope(P=0.04).In conclusion:1. The intraspecies difference in SMR is relatively large among juvenile carps.2. Individuals with higher SMR are therefore more active, presented with more frequentspontaneous swimming behaviour. Such characteristic may be of great help to foodacquisition,escape from predators and access to higher status.3. Individuals with higher SMR also have higher peak metabolic rate, indicating morepowerful digestive capabilities. 4. Other,the existing positive correlation between SDA peek and MO2active, suggestsfeeding and locomotion are two closely related physiological courses in fish.