Tracing escaped farmed salmon by means of naturally occurring DNA markers, fatty acid profiles, trace elements and stable isotopes

In 2003, the Ministry of Fisheries took the initiative to set up a national committee to investigate some questions regarding the tagging of farmed fish. In the same year, the Director of Fisheries set up the Tagging Committee with representatives of the aquaculture industry, the research community and the authorities, with the mandate to present a concrete range of tagging/tracing systems for farmed salmon. The committee found that two different methods of identifying escaped salmon should be investigate d further: coded wire tags and a case-based method (contingency method), based on naturally occurring characteristics of the fish. The project will test out methods of tracing escaped salmon by means of naturally occurring characteristics of the fish, such as DNA markers, fatty acid profiles, trace elements and stable isotopes. The salmon production chain consists of four stages: breeding populations, broodfish facilities, smolt producers and ongrowing facilities in the sea. The fish material is sort ed by size at each stage of production, and combined into new groups in order to optimise environmental factors and fish welfare. Therefore, reference samples must be collected at each sea pen location, when the aim is to identify the sea pen of origin o f escapes. In the project, salmon from the fish farms in the Hardangerfjord region and escaped salmon, will be collected. DNA profiles, lipid acid profiles, trace element composition and stable isotope composition will be established, and the usefulness of the various methods in tracing the sea pen of origin of escaped salmon will be investigated. The proposed project is a joint effort between research institutions and the industry: Institute of Marine Research, Norwegian Institute of Nature Research, N orwegian Veterinary College, VESO, NGU, SINTEF, Hardanger Fish Health Network, Rådgivende Biologer, University of Bergen, Danish Fisheries Research Institute, and University of British Columbia.