Regional impact from fin-fish farming in an intensive production area (Hardangerfjord, Norway)

Abstract

The Hardangerfjord is one of the largest salmon-farming areas in Norway, with an annual production of approximately 70,000 metric tonnes. The regional impact of fin-fish farming in a fjord environment was studied during 2008–2010. Ecological conditions in intertidal macroalgal and benthic deep basin communities were studied in addition to measurements of nutrients and chlorophyll-a values. Macroalgal communities in the intertidal zone and the deep water fauna communities showed a high ecological status in the intermediate part of the fjord and a good status in the inner part of the fjord. Faunal communities in the outermost basin indicate that the assimilative capacity for farm waste of this deep basin could be limited. Nutrients and chlorophyll-a values were within national thresholds defined as high water quality. The good ecological conditions of the parameters studied in the fjord show little evidence of a regional impact from the fish farming industry despite the intensive production level.

Key words:

• Regional impact
• benthic fauna
• macroalgae
• nutrients
• fin-fish farming

Acknowledgements

This study is a part of the EPIGRAPH (Ecological Processes and Impacts Governing the Resilience and Alternations in the Porsangerfjord and the Hardangerfjord) and was funded by the Ministry of Fisheries and Coastal Affairs and the Research Council of Norway. We thank the project leader of EPIGRAPH-Hardanger Øystein Skaala (IMR) for good and enthusiastic management of the project and Vidar Wennevik (IMR) for creating maps. We thank Lars Asplin (IMR), Svein Nygård and the crew of ‘RV Hans Brattström’ for valuable assistance during field work. We also thank Are Pedersen (NIVA) for help with the calculation of EQR-values for macroalgal communities. We appreciate valuable comments on the manuscript by Geir Helge Johnsen, Stein Fredriksen and two anonymous reviewers.

Editorial responsibility: Ketil Hylland