Overall Welfare Assessment (OWA) of Atlantic salmon

In Norway farmed fish are protected by the same welfare legislations as land animals. However, since there are no established methods to assess or document fish welfare, it is impossible to know how to comply with these regulations or control or enforce t hem. To address this need, we will construct an integrating model and tool for overall welfare assessment of farmed Atlantic salmon. To make it a science based and formalized method, we will use semantic modelling methodology, where welfare is defined as the quality of life as perceived by the animals themselves. Within this paradigm, both positive and negative aspect of welfare are considered, with the basis in basic needs and welfare indicators linked to scientific statements. The Salmon Welfare Index M odel (SWIM) will be developed for three levels of assessment (farmer, veterinary, scientist), and tested and validated in controlled laboratory experiments, as well as on a number of farm sites. The project will also develop and evaluate two visual indi cators of chronic welfare impairment, the eumelanin spot index, and the skin and fin integrity index. In controlled studies we will create conditions of both acute stress and chronic exposure to sub-optimal rearing environments (aggression and fluctuation of pCO2). The studies will be performed with salmon held under commercially relevant rearing densities, and on cannulated individual fish. In addition to registering welfare indicators in the SWIM model, we will sample fish for analysis of brain serotoni n biochemistry and expression of genes involved in neural plasticity and hypothalamus-pituitary-axis feedback. By using cannulated fish in the experimental situation it will be possible both to relate the CNS based indicators to already established physio logical stress indicators as well as to relate them to stress patterns over time. The correlation between various indicators will also be tested in field samples from a number of commercial farms.