Data from: Proactive avoidance behaviour and pace-of-life syndrome in Atlantic salmon

• Main Authors: Damsgård, Børge, Evensen, Tor H., Øverli, Øyvind, Gorissen, Marnix, Ebbesson, Lars, Ray, Sonia, Höglund, Erik
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2019
• Subjects: Coping style; Personality; Life history; Hypoxia; Stress; Cortisol; Lower Post; Atlantic salmon; Salmo salar
• Online Access: http://hdl.handle.net/10255/dryad.197421; https://doi.org/10.5061/dryad.4187519

Individuals in a fish population differ in key life history traits such as growth rate and body size. This raises the question of whether such traits cluster along a fast-slow growth continuum according to a pace-of-life syndrome (POLS). Fish species like salmonids may develop a bimodal size distribution, providing an opportunity to study the relationships between individual growth and behavioural responsiveness. Here we test whether proactive characteristics (bold behaviour coupled with low post-stress cortisol production) are related to fast growth and developmental rate in Atlantic salmon, Salmo salar. Boldness was tested in a highly controlled two-tank hypoxia test were oxygen levels were gradually decreased in one of the tanks. All fish became inactive close to the bottom at 70% oxygen saturation. At oxygen saturation level of 40% a fraction of the fish actively sought out to avoid hypoxia. A proactive stress coping style was verified by lower cortisol response to a standardized stressor. Two distinct clusters of bimodal growth trajectories were identified, with fast growth and early smoltification in 80% of the total population. There was a higher frequency of proactive then reactive individuals in this fast-developing fraction of fish. The smolts were associated with higher post-stress plasma cortisol than parr, and the proactive smolts leaving hypoxia had significant lower post-stress cortisol than the stayers. The study demonstrated a link between a proactive coping and fast growth and developmental ratio, and suggests that selection for domestic production traits promotes this trait cluster.