Juvenile Atlantic Salmon (Salmo salar) with relatively high standard metabolic rates have small metabolic scopes

Summary There is an established relationship between metabolism and behavioural dominance in several fish species, such that individuals with higher standard metabolic rates tend to be more dominant. It has also been suggested that metabolic scope increases with standard metabolic rate. Energetically expensive behaviours attributable to dominance, such as aggression, can be carried out to a greater extent within larger metabolic scopes. This study therefore tests the hypothesis that juvenile salmon with higher standard metabolic rates (which tend to be dominant) have larger metabolic scopes. It was found that salmon with high standard metabolic rates (corrected for body mass) in fact had smaller metabolic scopes than conspecifics with relatively low standard metabolic rates. Possible reasons for their potential dominance while having small metabolic scopes and high relative standard metabolic rates are discussed.