1. Department of Aquatic Resources, Swedish University of Agricultural Sciences, Institute of Marine Research , Turistgatan 5, 453 30 Lysekil , Sweden
2. Pacific Biological Station, Fisheries and Oceans Canada , Nanaimo, V9T 6N7 BC , Canada
3. Department of Mathematics, Simon Fraser University , Burnaby, V5A 1S6 BC , Canada
4. Leibniz Institute for Baltic Sea Research , Seestraße 15, 18119 Rostock , Germany
5. Department of Biological, Geological and Environmental Sciences, University of Bologna , Via Selmi 3, 40126 Bologna , Italy