First assessment of interchange of humpback whales between Oceania and the East coast of Australia

Abstract

The interchange of individual humpback whales between the wintering grounds of Oceania (South Pacific) and the east coast of Australia weredocumented by individual identification photographs collected from 1999 to 2004. Interchange was assessed using regional catalogues of flukephotographs, totalling 672 individuals from Oceania (represented by New Zealand, New Caledonia, Vanuatu, Fiji, Samoa, Tonga, Niue, Cook Island,French Polynesia and American Samoa) and 1,242 individuals from Hervey Bay and Byron Bay representing the southbound and the northboundmigration along the east coast of Australia (EA). Overall, there were seven documented movements between EA and Oceania. Four instances ofmovement of four individuals were documented between EA and the closest breeding grounds of New Caledonia. A further three movements wererecorded between EA and a small catalogue (n = 13) from the New Zealand migratory corridor. In contrast, during this same period, 20 cases ofinterchange were documented among nine breeding grounds: French Polynesia, Cook Islands, Niue, American Samoa, Samoa, Tonga, Fiji, Vanuatuand New Caledonia. The low level of interchange between Oceania and the east coast of Australia has important implications for understanding thestock structure and abundance of humpback whales in the South Pacific.