1. Faculty of Biosciences and Aquaculture Nord University 8049 Bodø Norway
2. Department of Arctic and Marine Biology, Faculty of Fisheries, Biosciences and Economics UiT–The Arctic University of Norway 9037 Tromsø Norway
3. Department of Biological Sciences University of Bergen 5020 Bergen Norway
4. Norwegian Institute for Nature Research 5006 Bergen Norway
5. Department of Hydrology and Water Resources Management Institute of Natural Resource Conservation, Kiel University 24118 Kiel Germany