1. Centre for Research into Ecological and Environmental Modelling, University of St Andrews, The Observatory, Buchanan Gardens, St Andrews, Fife, KY16 9LZ, United Kingdom
2. Alaska Fisheries Science Center, NOAA Fisheries, Marine Mammal Laboratory, Seattle, Washington 98115, USA
3. Chelonia Limited, The Barkhouse, Mousehole, TR196PH, United Kingdom