Humpback whales are giving birth far outside their expected tropical breeding zones, including during active migration, according to a new study that calls for a reassessment of current marine conservation strategies.
The research, led by the University of New South Wales and published in Frontiers in Marine Science, found that humpbacks (Megaptera novaeangliae) have been calving as far south as Tasmania and New Zealand—up to 1,500 kilometers beyond traditionally recognized breeding grounds.
The findings challenge long-held assumptions about whale reproduction. While it was previously believed that calves were born only in warm, protected waters in the tropics, researchers documented 209 calving events involving at least 169 individual calves along migratory routes. Of those, 118 were seen continuing their northbound journey shortly after birth.
The study combined more than three decades of data, including field observations dating back to 1991, government records, and documented stranding events along the coasts of Australia and New Zealand.
“These calves are being born hundreds of kilometers from where we thought the breeding areas were,” said study co-author Tracey Rogers. “We still have a lot to learn about the behavior of these whales during migration.”
According to the researchers, calves face immediate survival challenges once born: they must swim alongside their mothers through open waters, facing threats from predators, vessel strikes, and harsh environmental conditions—all while learning how to swim and navigate.
The study’s authors warn that current marine protected areas may not adequately cover these unexpected calving zones. They recommend expanding existing protections and launching public awareness initiatives to better safeguard humpback populations, which continue to face pressure from pollution, increased shipping traffic, and the accelerating impacts of climate change.
