1. Institute of Marine Research (IMR) and Hjort Centre for Marine Ecosystem Dynamics, P.O. Box 1870 Nordnes, N-5817 Bergen, Norway;
2. Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo, Norway
3. University of Aberdeen, Institute of Biological and Environmental Sciences, Zoology Bldg., Tillydrone Ave., Aberdeen AB24 2TZ, Scotland
4. School for Marine Science and Technology, Department of Fisheries Oceanography, University of Massachusetts Dartmouth, 706 South Rodney French Blvd., New Bedford, MA 02744-1221, USA
5. Bedford Institute of Oceanography, Dartmouth, NS B2Y 4A2, Canada