The future of salmon aquaculture depends on the adoption of alternative feed resources in order to reduce the need for fish meal and fish oil. This may include resources such as species from lower trophic levels, by-products and by-catch from fisheries and aquaculture, animal by-products, plants, genetically modified (GM) plants, nutritionally enhanced GM plants and products from microorganisms and GM microorganisms. Here, we report on a deliberative assessment of these alternative feed resources, involving 18 participants from different interest groups within (...) Norwegian salmon aquaculture. The participants defined a broad range of appraisal criteria concerning health and welfare issues, economical issues, environmental issues, and knowledge and social issues. A number of uncertainties, in the form of incomplete knowledge, diverging opinions, and context specific factors were identified when the participants evaluated the alternatives. Our findings support the need for more research on the suitability of alternative feed resources for farmed salmon. Additionally, the study underlines the importance of facilitating deliberative assessments in order to map the plurality of perspectives and explore qualitative aspects of uncertainty. Such initiatives improve the information base upon which decisions on future feed resources for farmed salmon are made. (shrink)