1. Institute of Marine Ecosystem and Fishery Science, Center for Earth System Research and Sustainability, University of Hamburg, Große Elbstraße 133, Hamburg 22767, Germany
2. Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, Bremerhaven 27570, Germany
3. Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife KY16 8LB, UK
4. Open Ocean Consulting, 3b Oaklands Road, Petersfield, Hampshire GU32 2EY, UK
5. Tethys Research Institute, Viale G.B. Gadio 2, Milan 20121, Italy