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.

This chapter reviews the major known monospecific and multispecific sponge aggregations in the world's oceans. They are shown to occur from the intertidal to abyssal depths, in tropical, temperate, and high latitudes and sometimes to create

Geodia barretti is a massive nearly spherical sponge that forms dense assemblages on the continental shelf of the North Atlantic and the Norwegian Sea. We studied the metabolism of individual sponges collected using a remotely operated vehicle and maintained in large tanks with high volumes of unfiltered water brought from 160 m depth. We used direct methods (In‐Ex) to measure excurrent flow rates, oxygen removed, and carbon and nutrient flux through the sponges. G. barretti had very low specific filtration (0.26 mL min−1 mL−1 sponge tissue) and low respiration (5.34 ± 0.98 nmol O2 min−1 mL−1 sponge tissue; 8.44 ± 1.51 μmol O2 h−1 g C−1) rates in comparison to other sponges. A net release of nitrogen was detected as NO3−. Bacteria were removed from the water filtered with up to 99% efficiency, yet comprised only 5% of the sponges′ total carbon budget; the remainder consisted of dissolved organic carbon and detritus. High bacterial removal was aided by the presence of a tight gasket of cells that surrounds the collar of each choanocyte filter. A test for potential bypass canals showed removal of fluorescent microspheres until they were excreted 5–12 h after feeding. Electron micrographs showed active uptake of Escherichia coli “fed” to the sponge as well as phagocytosis of symbiont microbes by sponge cells in the mesohyl. These data provide the first comprehensive study of metabolism in a deep‐water high microbial abundance sponge.

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