Rainbow trout husbandry: management of the stress response

The most important physiological and endocrinological changes occurring in rainbow trout subjected to common forms of aquacultural stress are described. It is demonstrated that plasma cortisol elevation, as a direct result of stress-induced activation of the hypothalamic-pituitary-interrenal axis, is a major factor responsible for the damaging effects of stress on survival, growth and reproduction. In the light of this knowledge, a series of practical guidelines is developed to enable fish farmers to minimize such damage. Future lines of research, to accelerate the rate of domestication of rainbow trout by means of selectively breeding fish with a reduced stress response, are discussed.