1. Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, St. Andrews, Fife KY16 8LB, UK
2. APEM Ltd, The Technopole Centre, Edinburgh Technopole, Milton Bridge, Nr Penicuik, Midlothian EH26 0PJ, UK
3. Centre for Research into Ecological and Environmental Modelling (CREEM), University of St Andrews, The Observatory, Buchanan Gardens, St. Andrews, KY16 9LZ, UK