Norwegian aquaculture has grown from its pioneering days in the 1970s to be a major industry. It is primarily based on culturing Atlantic salmon and rainbow trout and has the potential to influence the surrounding environment and wild populations. To evaluate these potential hazards, the Institute of Marine Research initiated a risk assessment of Norwegian salmon farming in 2011. This assessment has been repeated annually since. Here, we describe the background, methods and limitations of the risk assessment for the following hazards: genetic introgression of farmed salmon in wild populations, regulatory effects of salmon lice and viral diseases on wild salmonid populations, local and regional impact of nutrients and organic load. The main findings are as follows: (i) 21 of the 34 wild salmon populations investigated indicated moderate-to-high risk for genetic introgression from farmed escaped salmon. (ii) of 109 stations investigated along the Norwegian coast for salmon lice infection, 27 indicated moderate-to-high likelihood of mortality for salmon smolts while 67 stations indicated moderate-to-high mortality of wild sea trout. (iii) Viral disease outbreaks (pancreas disease, infectious pancreatic necrosis, heart and skeletal muscle inflammation, and cardiomyopathy syndrome) in Norwegian salmon farming suggest extensive release of viruses in many areas. However, screening of wild salmonids revealed low to very low prevalence of the causal viruses. (iv) From ∼500 yearly investigations of local organic loading under fish farms, only 2% of them displayed unacceptable conditions in 2013. The risk of eutrophication and organic load beyond the production area of the farm is considered low. Despite several limitations, especially limited monitoring data, this work represents one of the world’s first risk assessment of aquaculture. This has provided the Norwegian government with the basis upon which to take decisions for further development of the Norwegian aquaculture industry.

International audienceSargassum muticum, an invasive brown macroalga presently distributed along European Atlantic coasts from southern Portugal to the south coast of Norway, was studied on a large geographical scale for its production of phenolic compounds with potential industrial applications and their chemical and biological activities. S. muticum can produce high biomass in Europe, which could be exploited to supply such compounds. S. muticum was collected in Portugal, Spain, France, Ireland and Norway (three sites/country) to examine the effect of the latitudinal cline and related environmental factors. Assays focused particularly on polyphenols and their activities. Crude acetone-water extracts were purified using solid phase extraction (SPE) and antioxidant and antimicrobial activities of crude extracts and semi-purified fractions measured. Total phenolic content was assessed by colorimetric Folin-Ciocalteu assay and reactive oxygen species activities by 2,2-diphenyl-1-picrylhydrazyl, reducing power, β-carotene bleaching method and xanthine oxidase assay. Antibacterial activities were tested on terrestrial and marine strains to evaluate potential use in biomedical and aquaculture fields. Purified active phlorotannins, isolated by SPE, were identified using NMR. Phenolic contents differ clearly among countries and among sites within countries. Quality did not change between countries, however, although there were some slight differences in phlorethol type. Additionally, some fractions, especially from the extreme north and south, were very active. We discuss this in relation to environmental conditions and the interest of these compounds. S. muticum represents a potential natural source of bioactive compounds and its collection could offer an interesting opportunity for the future management of this species in Europe

Global expansion of salmon aquaculture is contingent upon finding new, large-capacity farming locations that are, increasingly, situated in dispersive environments with atypical ecological characteristics. The capacity of such sites to assimilate organic waste and the type and spatial extent of effects remain poorly understood. This study couples intensive spatial and temporal measurements of waste outputs with measurements of benthic ecological diversity and sediment biogeochemistry at a shallow dispersive site on the central west coast of Norway. Despite minimal visual changes to the seabed, pronounced biological effects were evident out to 600−1000 m away from the farm. Greatly enhanced faunal and microbial activity was tightly coupled with strong sediment respiratory responses in the form of oxygen uptake and ammonia efflux. The benthic response was highly dynamic, with rapid and prolific colonization by opportunistic fauna, followed by substantive recovery during the subsequent 7 mo fallowing period. The fate and pathways of farm waste through the environment was compartmentalized by converting measured parameters into equivalent carbon fluxes. During early production, approximately 30−40% of the waste was accounted for by the measured benthic processes, attributed to faunal respiratory activity and the physical properties including sediment type. Later in the production cycle, a sediment burial event was observed down-current from the farm. The remaining 60−70% of organic waste was assumed to be either assimilated in the water column, consumed by large, unquantified benthic fauna, or exported and dispersed. Shallow, dispersive sites therefore appear relatively resilient to acute near-field enrichment, but are also more likely to result in accumulative, far-field effects.

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