1. Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
2. Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
3. Joint Nature Conservation Committee, Quay House, 2 Station Road, Fletton Quays, Peterborough PE2 8YY, UK
4. South Atlantic Environmental Research Institute, Stanley Cottage, Ross Road, Stanley FIQQ 1ZZ, Falkland Islands
5. School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, Aberdeen, Scotland AB24 2TZ, UK
6. British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
7. National Oceanography Centre, Waterfront Campus European Way, Southampton SO14 3ZH, UK
8. Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
9. Department of Statistics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada