A slow comeback is taking shape off southern Africa, with new research finding blue and fin whale sightings have risen sharply in the southeastern Atlantic more than 40 years after commercial whaling ended.
Researchers compiled more than 60 years of confirmed sightings from Namibia and South Africa’s west coast, including stranded animals, and found 95 percent of observations were recorded since 2012.
The study, to be published in the African Journal of Marine Science, focused on Antarctic blue whales and fin whales, both heavily targeted during the industrial whaling era.
Between 1913 and 1978, an estimated 350,000 blue whales and 725,000 fin whales were killed, causing dramatic global population declines.
“Our results provide important evidence that these giants of the ocean are slowly recovering from the devastating impact of 20th century commercial whaling, which pushed them to the brink of extinction,” said study lead author Dr. Bridget James.
“Sightings remain rare, but they are becoming more frequent than in previous decades and with sustained protection, there is reason to believe this recovery can continue.”
Today, Antarctic blue whales are still listed as critically endangered on the International Union for the Conservation of Nature’s Red List.
Scientists estimate their population is at about 3 percent of pre-whaling numbers, but increasing slowly at around 5 to 8 percent per year.
Fin whales are classified as vulnerable, with populations thought to have recovered to more than 30 percent of historical levels and growing at around 4 to 5 percent annually.
Researchers said both species remain difficult to study because they travel vast distances and spend much of their lives in remote Antarctic waters. Data on migration routes and possible breeding grounds, including the southeastern Atlantic, has been limited.
“Historic whaling data suggests that the southeast Atlantic may once have been an important nursery area for both blue and fin whales,” said Dr. James, from the University of Cape Town, South Africa.
Until now, researchers had very little information on the whales’ recent presence in the region.
To fill that gap, the team compiled verified sightings and strandings recorded between 1964 and March 2025, focusing on the Benguela upwelling ecosystem off Namibia and the west coast of South Africa.
Blue whales were recorded infrequently, with 12 sightings, one stranding and five additional published records.
Fin whales were seen more often, with 76 sightings documented and six strandings.
Blue whales were most often seen between late spring and autumn, while fin whales appeared to occur year-round.
“As populations slowly rebuild, we would expect to see these whales begin reoccupying parts of their historical range,” said study co-author Dr. Simon Elwen, from the University of Stellenbosch, South Africa.
“The increase in sightings and strandings is consistent with this gradual recovery, although increased offshore observation efforts may also contribute.”
Researchers said threats remain, including ship strikes, entanglement in fishing gear, and pollution or climate-driven changes in ocean ecosystems.
“Even with more than 50 years of recovery since the end of commercial whaling, we could only compile 12 records of blue whales off our coast,” Dr. Elwen said.
The researchers recommend expanding passive acoustic monitoring, increasing trained observer coverage in commercial sectors, and incorporating whale distribution data into marine spatial planning to safeguard their slow but important recovery.
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