Satellite tracking and sighting data analyses of Southeast Pacific humpback whales (Megaptera novaeangliae): Is the migratory route coastal or oceanic?

This paper presents an analysis of the migra-tion movements of Southeast Pacific humpback whales (Megaptera novaeangliae) based on satellite and sighting data. We used informa-tion obtained from six humpback whales tagged off the coast of Ecuador between August and September 2013, and sighting information from oceanographic cruises and seismic prospection studies. Tagged humpback whales were followed along the west coast of South America, and in one case off the Antarctic Peninsula, for between 11 and 72 d. Distance covered by tracked whales was between 920 and 8,670 km. While available sight-ing data indicated that humpback whales follow a coastal route, satellite tracking data show that single adults use a more direct offshore route and mother/calf pairs tend to follow the longer coastal route. A 4-d period of irregular movements by a mother with a calf off central Peru suggested foraging behavior in this area characterized by intense upwelling processes. On the other hand, the humpback whale that reached Antarctic waters by mid-October quickly moved 200 km off the Antarctic Peninsula, probably because the zone was still covered by ice. We also found differ-ences in travel speed between age/sex classes of humpback whales with mother/calf pairs traveling about 30% slower than single adults. The aver-age humpback whale swim speed ranged between 65.5 and 169 km.d^-1. Our information provides a first examination of potential routes used by this whale population and highlights the need for a regional approach in appropriately addressing the migratory behavior and threats to the species during its annual migration.