1. University of California Santa Cruz Ecology and Evolutionary Biology Department, , 130 McAlister Way, Santa Cruz, CA 95064, USA
2. University of Washington Cooperative Institute for Climate, Ocean, and Ecosystem Studies, , 3737 Brooklyn Ave NE, Seattle, WA 98105, USA
3. Aarhus University Department of Ecoscience – Marine Mammal Research, , Frederiksborgvej 399, 4000 Roskilde, Denmark
4. Sydney Institute of Marine Science , 9 Chowder Bay Road, Mosman, NSW 2088, Australia
5. University of California Santa Cruz Institute of Marine Science, , Santa Cruz CA, USA
6. University of St. Andrews Centre for Research into Ecology and Environmental Modelling, , St. Andrews, KY16 9LZ, UK
7. University of British Columbia Marine Mammal Research Unit, Institute for the Oceans and Fisheries, , 2022 Main Mall, Vancouver, BC V6T 1Z4, Canada
8. Oregon State University Fisheries, Wildlife, and Conservation Science Department, , Hatfield Marine Science Center, 2030 SE Marine Science Driver, Newport, Oregon 97365, USA