1. Graduate School of Oceanography; University of Rhode Island; Narragansett RI 02882 USA
2. School of Ocean Sciences; Bangor University; Menai Bridge Anglesey LL59 5AB UK
3. Wageningen Institute for Marine Resources and Ecosystem Studies; 1970 AB IJmuiden the Netherlands
4. Centre for the Environment; Fisheries and Aquaculture Science; Lowestoft Laboratory; Pakefield Road Lowestoft Suffolk NR33 0HT UK
5. School of Environmental Sciences; University of East Anglia; Norwich Research Park Norwich NR4 7TJ UK
6. School of Aquatic and Fisheries Science; University of Washington; Seattle WA 98195 USA