A study published in the African Journal of Marine Science has documented a marked increase in sightings of Antarctic blue whales and fin whales in the southeastern Atlantic since 2012. Researchers from the University of Cape Town, Sea Search, and Stellenbosch University compiled verified sightings and strandings recorded between 1964 and March 2025 along the Benguela upwelling ecosystem off Namibia and South Africa's west coast.
Commercial whaling between 1913 and 1978 killed an estimated 350,000 blue whales and 725,000 fin whales globally. Antarctic blue whales remain classified as Critically Endangered by the IUCN, at roughly 3% of pre-whaling numbers, while fin whales are listed as Vulnerable at over 30% of historic levels.
The dataset includes 12 blue whale sightings, one stranding, and five published records, alongside 76 fin whale sightings and six strandings. Ninety-five percent of all observations occurred after 2012. Blue whales were seen mainly between late spring and autumn, whereas fin whales appeared year-round.
Lead author Dr. Bridget James said the trend is consistent with gradual population recovery and reoccupation of historical range, noting the southeast Atlantic may once have been an important nursery area. Co-author Dr. Simon Elwen cautioned that increased observer effort, particularly from seismic survey vessels, may also contribute to the rise in records.
Both species still face threats from ship strikes, fishing gear entanglement, underwater noise, pollution, and climate-driven ecosystem changes. The authors emphasize that current numbers remain low and systematic scientific monitoring is lacking.
The study recommends expanding passive acoustic monitoring, increasing trained observer coverage in commercial sectors, and integrating whale distribution data into marine spatial planning to protect the ongoing recovery.
Research limitations include the opportunistic nature of many records and the difficulty of studying wide-ranging species that spend much of their lives in remote Antarctic waters.
The findings represent a measurable sign of resilience for two of the largest whale species, though full recovery remains a distant prospect.
After commercial whaling nearly erased them, blue and fin whales are slowly reclaiming the southeast Atlantic
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