1. Cooperative Institute for Marine Resources Studies, Oregan State University and NOAA Pacific Marine Environmental Laboratory, 2030 SE, Marine Science Drive, Newport, OR 97365, USA
2. NOAA National Marine Mammal Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115-6349, USA
3. Institute of Earth Sciences, University of Iceland, Öskju, Sturlugötu 7, IS-101 Reykjavík, Iceland