![]() ![]() Several theories exist as to what drives this behavior, and include the hypotheses that it is a response to the need to feed in cold waters and reproduce in warm waters for calf thermoregulation or killer whale predation evasion purposes, a response to the need to undergo epidermal molt, or even a response to shifts in oceanographic conditions between glacial maxima. Humpback whale ( Megaptera novaeangliae) migrations, with recorded one-way distances of up to 8461 km, are part of an annual cycle consisting of journeys between tropical calving grounds in winter and high-latitude feeding grounds in summer. This multi-year study sets a baseline against which the effects of climate change on humpback whales can be studied across years and conditions and provides an excellent starting point for the investigation into humpback whale migration. Results suggestive of stratification by sex and reproductive status were found for departure date and route choice. The linear regression assessing whether departure date affected migration speed showed suggestive but inconclusive support for a positive trend between the two variables. The state–space model showed almost no instances of ARS along the migratory route. Humpbacks were widely dispersed geographically during the initial and middle stages of their migration, but convened in two convergence regions near the southernmost point of Chile as well as Peru’s Illescas Peninsula. The length of individually derived tracks ranged from 645 to 6381 km. ![]() The 16 whales were tracked for a mean of 38.5 days of migration (range 10–151 days). Resultsģ5,642 Argos locations from 16 tagged whales from 2012 to 2017 were collected. A Bayesian hierarchical state–space animal movement model (HSSM) was utilized to investigate the presence of Area Restricted Search (ARS) en route. Satellite locations were used to demonstrate migratory corridors, while the impact of departure date on migration speed was assessed using a linear regression. We present new information on satellite-derived offshore migratory movements of 16 Breeding Stock G humpback whales from Antarctic feeding grounds to South American calving grounds. Until now, no study has provided a continuous description of humpback whale migratory behavior from a feeding ground to a calving ground. Despite exhibiting one of the longest migrations in the world, half of the humpback whale migratory cycle has remained unexamined. ![]()
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