A humpback whale has made a 15,000km journey from Brazil to Australia, marking what researchers believe is the longest distance ever documented between sightings of an individual humpback.
Discovery of the Record Journey
The whale was first photographed in 2003 at the Abrolhos Bank, Brazil's main humpback whale nursery, off the coast of the north-eastern state of Bahia. In September 2025, it was spotted again in Hervey Bay off the Queensland coast, representing a travel distance of about 15,100km.
Stephanie Stack, a PhD candidate at Griffith University and co-author of new research published in Royal Society Open Science, said it was “extraordinary to photograph a whale that’s gone this distance – it has never happened before”.
“This particular whale had not been sighted for 22 years, which is really remarkable in and of itself,” Stack said.
Identification Through Fluke Photos
The whale was detected in a repository of photos on the platform Happywhale, to which researchers and citizen scientists can contribute whale sightings. The photographs allow individual animals to be identified by their flukes – the underside of their tails.
A whale fluke is “unique to each humpback whale, very similar to the way fingerprints are unique to humans,” Stack said. Flukes are identifiable through their shape, patterns of black and white pigmentation, and distinctive features such as scars.
The Happywhale platform, co-founded by study co-author and Southern Cross University whale biologist Ted Cheeseman, uses an AI algorithm to identify matches, akin to facial recognition in humans.
Another Long-Distance Traveler
Another whale was photographed in Hervey Bay in 2007 and seen again in the same area in 2013. Six years later, it was spotted off the coast of São Paulo. The distance between these two breeding grounds is about 14,200km.
The two whales are “the first recorded exchange in both directions” between the Brazilian and eastern Australian humpback whale populations, the researchers wrote. “Resighting intervals of six and 22 years suggest that these are rare, possibly single-lifetime events, rather than regular migratory shifts.”
The study drew on 19,283 fluke photos collected between 1984 and 2025 from eastern Australia and Latin America – and the two whales accounted for “only 0.01% of identified whales”.
Uncertainties and Implications
“One of the drawbacks to doing photo identification research is we only have … two points,” Stack said. “We know where it started, and we know where it ended up, but we don’t know anything about what happened in between.”
She pointed out that the animals could have travelled farther than the straight-line distances between the Brazilian and Australian coastlines – and that it was unclear what routes they had taken to reach their destinations.
The typical migration route for an Australian humpback whale is between feeding grounds in Antarctic waters and breeding grounds near the Great Barrier Reef.
“Each year, they do a full loop from feeding grounds to breeding grounds and then back again to feeding grounds,” Stack said – a round trip of about 10,000km.
Conservation and Climate Change
The discovery of the two whales’ long journeys across the open ocean was “a good reminder that conservation of our marine resources needs to be collaborative between nations, because these are migratory animals that move across borders and between countries”, Stack said.
It was “very likely” that climate change would affect migration patterns in future, she said, pointing to dramatic changes in the Southern Ocean feeding grounds, with Antarctic krill populations under threat.
