1. Marine Vertebrate Ecology Research Group; School of Biological Sciences; The University of Queensland; St Lucia, Queensland 4072 Australia
2. School of Veterinary Science; The University of Queensland; Gatton Queensland 4343 Australia
3. Cetacean Ecology, Behaviour and Evolution Lab; School of Biological Sciences; Flinders University; Adelaide South Australia 5001 Australia
4. South Australian Research and Development Institute (SARDI); Aquatic Sciences; 2 Hamra Avenue West Beach South Australia 5024 Australia