Feeding grounds of the eastern South Pacific humpback whale population include the South Orkney Islands

This paper reports on two photo-identified humpback whales ( Megaptera novaeangliae ) that were sighted in different years in the proximity of the South Orkney Islands, at the boundary between the Scotia and Weddell seas (60 o 54.5’S – 46 o 40.4’W and 60 o 42.6’S – 45 o 33’W). One of the whales had been previously sighted off Ecuador, a breeding ground for the eastern South Pacific population. The other whale was subsequently resighted in Bransfield Strait, off the western Antarctic Peninsula, a well-documented feeding ground for the same population. These matches give support to a hypothesis that the area south of the South Orkney Islands is occupied by whales from the eastern South Pacific breeding stock. Consequently, we propose 40 o W as a new longitudinal boundary between the feeding grounds associated with the eastern South Pacific and western South Atlantic breeding stocks. Keywords: Humpback whale; photo-identification; breeding stocks; migration; South Orkney Islands; Southern Ocean (Published: 20 March 2012) Citation: Polar Research 2012, 31 , 17324, DOI: 10.3402/polar.v31i0.17324