1. Sea Mammal Research Unit, Gatty Marine Laboratory, University of St Andrews, Fife KY16 8LB, Scotland, U.K.
2. College of the Atlantic, 105 Eden Street, Bar Harbor, ME 04609, U.S.A.
3. Department of Population Biology, University of Copenhagen, DK‐2100 Copenhagen Ø, Denmark
4. Northeast Fisheries Science Center, 166 Water Street, Woods Hole, MA 02543‐1026, U.S.A.
5. Greenland Institute for Natural Resources, P.O. Box 570, 3900 Nuuk, Greenland
6. Biopsychology Programme and Ocean Sciences Centre, Memorial University of Newfoundland, St Johns, Newfoundland A1C 5S7, Canada
7. Center for Coastal Studies, PO Box 1036, Provincetown, MA 02657, U.S.A.
8. Marine Research Institute, Skulagata 4, P.O. Box 1390, 121 Reykjavik, Iceland
9. Institute for Marine Research, P.O. Box 1870, Nordnes, 5024 Bergen, Norway