Caractérisation de l’adaptation comportementale des téléostéens en élevage : plasticité et effets de la domestication

The farming of aquatic animals has started recently in comparison with that of terrestrial species which domestication started 10 500 years ago. Aquaculture is however the fastest growing animal food-production sector. This sector has now to face several challenges threatening its sustainability. Indeed, aquaculture future largely depends upon the reduction of the reliance on feeds based ingredients derived from wild fishery resources, upon a better knowledge of fish domestication process and of the adaptation mechanisms and related welfare potential. The present work aims at a better understanding of the adaptation to farming conditions through a behavioural approach based on the comparison between wild vs. domesticated populations of three species: a marine species, sea bass (Dicentrarchus labrax), two freshwater species, arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta). The thesis is divided into two parts which objectives were : 1) to test the impact of biotic and abiotic factors selected based on their importance in aquaculture (shelter, plant-based diet, egg size and social environment, size grading, and fasting effects) on sea bass and artic charr behavioural plasticity (behavioural modifications in response to environmental changes). Behavioural indicators (feeding behaviour, mobility, swimming activity, exploration, personality traits) were investigated and completed by the analysis of physiological variables (blood parameters) and growth performances. 2) to characterize the domestication effect and the interplay of aging and ontogeny on behaviour (swimming activity, escape response rate, exploration and cognition) through the comparison between wild vs. domesticated sea bass and brown trout at different ages and under different experimental conditions (challenges, maze).