Humpback whales were born during migration, far from tropical

The fragile newborn hunched whale fish enters the world much further than scientists have previously imagined, and during their most vulnerable stages of life, busy transport roads and urban coastlines. This surprising discovery challenges long-standing belief in whale migration patterns and raises urgent questions about the earliest protection of these ocean giants.

The UNSW-led study, published yesterday in the field of marine science, documented witnesses of more than 200 newborn first-born calves from Tasmania to the South Island of New Zealand, a staggering 1,500 km south of the area traditionally recognized as a calving site.

Birth on the highway

For decades, scientists believed that humpback whales have migrated their epic to tropical waters, specifically for delivery in warm, protected areas. The new study shows that they are much more adaptable, with mothers connecting what researchers call the “hunchou satellite highway” (the migration route connecting Antarctic feedlots to tropical breeding areas.

“Hundreds of humphead calves were born at established breeding sites,” said Dr. Tracey Rogers of the University of New South Wales, senior author of the study. “Treatment along the ‘hunchhead satellite highway’ refers to these fragile calves of not-strong swimmers growing much earlier than those born at breeding sites.”

What is particularly striking is that most alma alumni continue to migrate north after birth rather than staying. This challenges the basic assumptions about driving whale migration patterns.

An amazing discovery

Research begins with accidental encounters. “In July 2023, during a whale watching trip, I met a mom and a calf at Newcastle Port (Newcastle Port (the busiest port in eastern Australia),” said Jane McPhee-Frew, PhD candidate at the University of New South Wales, and the lead author of the study. “The calf is small and obviously brand new. What are they doing there? But none of my travel colleagues seem to be surprised.”

The observation triggered a collaborative survey that combines data on citizen scientists, government investigations and reporting barriers. The researchers recorded 209 newborn calves, including direct observation of 11 births.

The southernmost calf was found near Port Arthur, Tasmania – about 43 degrees south latitude – making it the highest latitude humpback whale ever recorded in the world.

Why this matters

This discovery is of great significance to the protection of whales. Newborns face many threats in busy, developed coastal waters, including:

• Ship strikes in busy transport lanes
• Entanglement in fishing gear and shark nets
• Noise pollution in ships and coastal developments
• Chemical pollutants are concentrated near cities
• Destruction of recreational boats

Instead of spending the first day of fragile on protected tropical waters, these calves must immediately embark on a arduous journey through Australia’s busiest waterways.

“Maybe something has happened in our oceans that we haven’t discovered yet,” said Dr. Vanessa Pirotta of Macquarie University.

Not a new behavior

Although these findings appear to be recent developments, there is evidence that temperate births may always occur, but when whales populations are severely depleted by commercial whaling, it just doesn’t notice it.

“I think this pattern is likely to be there all the time, but the whales from the view cover the whales very little,” McPhee-Frew said. “The humpback crowd in eastern Australia narrowly escaped, but now there are 30, 40, or 50,000 people in this crowd alone. It didn’t happen overnight, but the recovery of humpback whales, and the regression of their entire behavior and distribution, just shows that good policies are constructed in good science and we can have excellent results.”

Historical records, including the 19th-century whaling log, contain references to young calves of similar latitudes, supporting the theory that such behavior is not new.

Rethinking whale migration

This discovery raises a fascinating question: Why did humpback whales migrate to tropical waters if they could give birth south? Why did the mother continue swimming thousands of kilometers northward after giving birth during immigration, dragging a fragile newborn?

The study cannot answer these questions explicitly, but suggests that whales migration may be more complicated than previously understood. Instead of the different “feeding grounds” and “breeding grounds” connected by migration routes, the head backs appear to use continuity of habitat and behavior throughout the scope.

Community efforts

The study represents an extraordinary collaboration between scientists, whale watch operators, government wildlife institutions and citizen scientists. Most observations come from commercial whale watching tours and coastal photographers, emphasizing the value of community involvement in marine research.

“This study is based on opportunistic observations,” McPhee proposed. “This data is perfect for answering questions like ‘Is there a newborn whale here?’ However, it seems that our explanation is too far away and we may see more calves, or we’re seeing more time.

These findings highlight the need for the presence of vulnerable nascent whales in areas they had not expected before. Although there are already legal protections in Australian waters against alma maters in Australian waters, including maintaining a distance of at least 300 meters, many recreational rowers may not be aware of these regulations or the existence of newborns.

As populations of humptop satellites continue to recover from near extinction, this study shows that there is still much to learn about one of the most iconic species in the ocean. The next challenge is to ensure that these newborns survive increasingly busy coastal waters.

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