Recovery of large baleen whales in the South-East Atlantic

Data in support of the following publication: <b>Recovery of large baleen whales in the South-East Atlantic: Recent increased presence of blue (</b><b><i>Balaenoptera musculus</i></b><b>) and fin whales (</b><b><i>Balaenoptera physalus</i></b><b>).</b>Southern Hemisphere blue (<i>Balaenoptera musculus intermedia</i>) and fin (<i>Balaenoptera physalus quoyi</i>) whale populations were heavily impacted by commercial whaling. Historic whaling data suggests that the Southeast Atlantic was an important nursery and feeding area for both species. In this note we collated published and opportunistic sightings and strandings from Namibia and South Africa, for both species, between 1964 and March 2025. Blue whale sightings were sparse, with 12 sightings, one stranding and five published records, while fin whales were seen more frequently (76 sightings and six strandings). Blue whale sightings peaked between late spring and autumn in the Benguela while fin whales appear to be present in the Benguela throughout the year. While the number of sightings of both species are relatively low, they are steadily increasing as these whale populations recover, with 95% of observations recorded since 2012. Given the vulnerability of these species and the anthropogenic risks they face across their global ranges, their distribution and species-specific risks should be investigated and as far as possible included in marine spatial development plans.