Parental stress-coping styles affect the behaviour of Rainbow trout Oncorhycus mykiss at early developmental stages

This work examines behaviour responses in yolk sac fry originating from strains selected for high (HR) or low (LR) plasma cortisol response to a standardised stressor. The results shows that yolk sac larvae originating from the HR strain is more sensitive to environmental stressors, in that they showed a shorter reaction time to low oxygen levels. Previous studies on adult and juvenile individuals from these strains have demonstrated a number of correlated physiological and behavioural differences. In yolk sac larvae growth and development depend mainly on internal factors, which suggest that at least some aspects of stress coping styles are inherent to the individual, before factors such as exposure to social experience or variable access to food resources could modify behavioural strategy.