An investigation shows that the epic migrations of the humpback whales to tropical waters are not as essential as it was believed to give birth: the young can be born as south as Tasmania or New Zealand, 1,500 kilometers further south than it was believed. Scientists affirm that these results refute the rooted beliefs about the migration of humpback whales and that, to protect these unexpected offspring, we need to improve awareness about the expansion of childbirth areas.
“Hundreds of humpback whales were born quite far from the established reproduction areas,” said Dr. Tracey Rogers, from the University of Nueva Gales del Sur, the main author of the article published in Frontiers in Marine Science. “Giving birth to the ‘Humpback Highway Highway’ means that these vulnerable young, which are not yet good swimmers, are forced to swim long distances much before if they had been born in the reproduction areas,” he says.
“Parallel to my studies, I work as a marine guide,” said Jane McPhee-Frew, a doctoral candidate and first author of the University of Nueva Gales del Sur. “In July 2023, during a whale sighting excursion, I found a mother whale and her breeding at the entrance of the port of Newcastle, the most busy sea port in eastern Australia. The breeding was tiny, obviously newborn. What did they do there? But none of my tourism colleagues seemed surprised.”
THE WALLS WAY
Inspired by the sighting of McPhee-Frew, the researchers investigated the breeding area of the humpback whales in Australia and New Zealand. They combined data on citizen science observations, government surveys and reported variations. The whale project of the Cook Strait of the New Zealand Conservation Department provided data on migration surveys, and the Australian state Wildlife Departments provided information on variations since 1991.
The scientists identified 209 records of newborn offspring, including 11 births, 41 variations and 168 observations of living young, which represents at least 169 individuals. They had data on the travel address of 118, which indicated that the whales continued their migration north after childbirth.
“The humpback whales populations undertake extensive long -distance migrations from the Antarctic Ocean to their reproduction zones in the tropics,” said co -author Adelaide Dedden, of the National Parks and Wildlife Service of Australia. “They depend largely on body reserves from a huge amount of Kril Antarctic to cover the physiological costs of trip and reproduction.”
The humpback whale, which was found in the highest latitude, was found in Port Arthur, Tasmania, 1,500 km further south than it was believed that the humpback whales could give birth. The birth registered in the highest latitude was observed just a little further north, in Kaikoura, New Zealand.
The majority of living young observations were recorded from 2016, and two thirds of the observations were made in 2023 or 2024. Meanwhile, comparisons with historical texts and whale hunting records indicate that young born during migration were observed before the population collapsed due to hunting.
“I think it is very likely that this pattern has always existed, but the low number of whales hid it,” said McPhee-Frew. “The humpback whales population of eastern Australia escaped by little from extinction, but now there are 30, 40 or 50,000 only in this population. It does not happen overnight, but the recovery of humpback whales and the return to their complete range of behavior and distribution shows that with good policies based on solid science we can obtain excellent results.”
Migration reasons
Migrar consumes energy and leaves vulnerable offices to predators. Why are humpback whales risk to migrate if they can give birth more to the south? This study does not answer this question, but it is possible that other factors promote migration, or that the benefits of usually giving birth to tropical waters overcome the risks for a possible breeding born on the road. Although the data provided by the Department of Biodiversity, Conservation and Attractions of Western Australia identified a possible parenting zone in the Flinders Bay, it is likely that most of the young nadan much further north, in the tropics.
The findings have implications for conservation. Some of the observed young were injured, and scientists claim that protected areas are needed to expand awareness campaigns on protection measures and carry out more research on the habitats used by humpback whales during their migration to protect the young.
“This study was based on opportunistic observations,” said McPhee-Frew. “These data are excellent to answer questions such as: ‘Are there newborn whales here?’
“We can only document what we see,” added Co -author of Vanessa Pirotta, from Macquarie University. “Maybe things that we have not discovered happen in our ocean.”
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