Abstract
Artificial rearing of fish destined for deliberate release into the natural environment as juveniles (sea-ranching) is frequently practiced in an attempt to restore anadromous salmonid populations. The hatchery environment clearly imposes a different selection regime on the fish than the wild habitat, and there are indications of that sea-ranching might alter the stress coping style of the fish. Thus, there are really need for comprehensive investigations on hatchery effects on brown trout stress coping style. If the purpose of the sea-ranching programme is to preserve strains, such alternations of coping style counteracts the essence of the preservation work. The aims of the present proposal is to: (1) verify the presence of differing stress coping styles in brown trout, (2) to investigate if the frequency distribution of different coping styles differs between different brown trout populations, and (3) to clarify the effect of sea-ranching on the frequency distribution of different coping styles in brown trout.
Sweden