| Summary: | Arctic charr (Salvelinus alpinus) is the northernmost distributed freshwater fish and considered to be the most cold-adapted salmonid. In overall, Iceland is graded as the largest worldwide producer and its system considered as sustainable farmed system. Despite that, no study has yet targeted the welfare state of Arctic charr, although there is a growing interest regarding animal welfare in food production systems. Animal personality has been reported in a wide range of species across the animal kingdom, including fish, and its adaptive importance has become a central subject in diverse disciplines ranging from behavioural ecology to fish welfare. In aquaculture, animals are often raised in plain housing conditions and such environments could severely restrict the natural behavioural repertoire of animals, and hence may compromise their welfare. Therefore, enriched rearing conditions in aquaculture have been used since the last decade to improve the welfare and the performances of the farmed species. The aims of this study are to investigate how an environmental enrichment affects the personality traits expression and their correlation (i.e., behavioural syndrome) as well as potential association with brain characteristics and growth for Arctic charr welfare implication. I found that physical environmental enrichment induces boldness consistency across long term period (Chapter 1), behavioural syndrome (Chapter 2), shyer individuals (Chapter 1), a lower brain volume, higher growth performance as well as a positive correlation between boldness and olfactory bulbs and growth rate (Chapter 1 & 2). Futhermore, I found that individual and group risk taking are repeatable but not cross – context consistent (Chapter 3). These results are implemented in the nature and function-based welfare framework and brings new insights into behavioural traits development. Bleikja (Salvelinus alpinus) hefur norðlægustu útbreiðslu ferskvatnsfiska og er álitinn vera sá laxfiskur sem er aðlagaður að kaldasta umhverfinu. Ísland ...
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