1. Department of Biology ‐ Aquatic Ecology Lund University Ecology BuildingSE‐223 62 Lund Sweden
2. National Institute for Aquatic resources ‐ Section for Marine Living Resources Technical University of Denmark Jægersborgs alle 1 DK‐2920 Charlottenlund Denmark
3. National Food Institute Technical University of Denmark Søltofts plads Building 221 DK‐2800 Kgs. Lyngby Denmark
4. Department of Biology ‐ Theoretical Ecology Group and Hjort Centre for Marine Ecosystem Dynamics University of Bergen N‐5020 Bergen Norway
5. Department of Environmental and Life Sciences ‐ Biology Karlstad University SE‐651 88 Karlstad Sweden