| dc.description.abstract | The fish farming industry has continued to increase over the last years, and salmon fish farms in Norway continue to grow in numbers. With this growing aquaculture, there is also a larger need to quantify the environmental effects that follow a net-pen fish farm, and to investigate which areas are best suited for fish farming. Also, the role of hydrodynamics could potentially alter the effects that the effluents have on the benthic ecosystem. This study conducted a comparison of the benthic (1) abundance, (2) biomass, (3) biodiversity and (4) carbon uptake, at two different fish farms located in high and low water-flow environments, as well as control samples further away from each of the fish farms, to get information on how the ecosystem functions under the different hydrodynamic regimes. The carbon uptake by macrofauna was measured using stable isotope pulse chase experiments with 13C. Abundance, biomass and carbon uptake did not differ significantly between the two fish farms, while biodiversity was significantly higher under the high flow fish farm than under the low flow fish farm. Both fish farm sites are regarded as organically enriched, although the low flow fish farm site were more heavily enriched, with a more typical r-selected community structure and the large presence of the opportunistic polychaetes Capitella capitata, Vigtorniella ardabilia, and Palpiphitime lobifera, the latter two being bacterivores. With the benthic community under both fish farms being equally effective in carbon uptake, although by different agents, either hydrodynamic regime can situate a well- functioning ecosystem.  | en_US |
