Stress coping styles in teleost fish – neuroendocrine mechanisms and implications for aquaculture and conservation biology
Divergent stress coping styles referred to as proactive and reactive have been described in various teleost species. When challenged by a stressor proactive individuals display an active response, for example, arousal, active avoidance, display, and aggression whereas reactive individuals when challenged by the same stressor show a passive response characterized by behavioural inhibition. These divergent stress coping styles are also reflected in autonomic, neuroendocrine, and physiological stress responses. In fights for social dominance proactive fish appear to have an advantage. Moreover, proactive animals form behavioural routines whereas those displaying a reactive coping style are more plastic in their behaviour. Thus, proactive fish may do better in a stable predictable environment whereas reactive fish could be more successful in a variable non-predictable environment. This could result in a non-intentional selection for proactive fish in hatcheries. To a large extent coping style appear to be controlled by heritable factors but environmental effects are also obvious. For instance, fish subjected to social subordination show a more reactive coping style. The brain monoaminergic systems are known to be important in the control of stress responses and aggression. Moreover differences in brain monoaminergic functions appear to be related to differences in stress coping style. Also, brain monoaminergic activity is greatly affected by social stress and especially the brain serotonergic system is important in mediating behavioural effects of social subordination. Using zebrafish as a model we are trying to identify genetic and epigenetic mechanisms controlling stress coping styles in fish. These studies are complemented by studies on Baltic salmon.
Host: Robert Arlinghaus