Oxygen consumption and swimming performance in Arctic charr with different pigmentation patterns

Pigmentation in animals often reflects behavioural and physiological traits, such as health status, stress responsiveness, and dominance. Individual variation in stress response and behaviour has earlier been proposed to be connected to differences in metabolism. The aim of this study was to investigate the connection between pigmentation, behaviour, and oxygen consumption in Arctic charr (Salvelinus alpinus). In this species, we have earlier found an association between number of carotenoid spots on the skin and physiological response to stress (stress coping style). Swimming endurance and respiration rates were estimated from video recorded behaviour and oxygen consumption in a swim tunnel. Flow velocity was kept as 1.6 BL (body lengths) s−2 for 60 min, and oxygen consumption (mg min−1 g−1) during that time was used as a proxy for metabolism. Oxygen consumption was negatively correlated with number of spots. Also behaviour scores from a principal component analysis varied with pigmentation, with a negative correlation between number of spots and behaviour scores connected with endurance. Fish with fewer spots rested more against the rear of the chamber, and fish with more spots were sooner, and more often, pressed to the rear grid by the water current. The variation in oxygen consumption in the swim tunnel indicates a relation between respiration rate, swimming endurance, and pigmentation in the Arctic charr. With earlier findings on covariations between spot numbers and stress coping in this species, there seems to be connections between stress coping style, behaviour, and metabolism. Thus, it would be possible to identify individual expression of these features, based on the pigmentation patterns of the fish.