Blue and Fin Whale Sightings Increase in Southeast Atlantic

Sightings of blue whales and fin whales in the Southeast Atlantic have increased over the last four decades. This suggests a slow recovery for the world's two largest whale species. Researchers compiled over 60 years of confirmed sightings and strandings from Namibia and South Africa's west coast. Ninety-five percent of these observations occurred since 2012.

Antarctic blue whales (Balaenoptera musculus intermedia) and fin whales (B. physalus quoyi) were heavily hunted during the industrial whaling era. An estimated 350,000 blue whales and 725,000 fin whales were killed between 1913 and 1978. This led to dramatic global population declines. The International Union for the Conservation of Nature (IUCN) Red List still classifies Antarctic blue whales as Critically Endangered. Their population is estimated at about three percent of pre-whaling numbers.

Fin whales are classified as Vulnerable. Their populations are thought to have recovered to more than 30 percent of historical levels. The study focused on the Benguela upwelling ecosystem. This is a nutrient-rich region off Namibia and the west coast of South Africa. Researchers compiled verified sightings and strandings from 1964 to March 2025. This helped understand trends in whale presence and seasonality.

Blue whales were recorded infrequently, with 12 sightings, one stranding, and five additional published records. Fin whales were encountered more often, with 76 sightings and six strandings documented. Blue whales were most often seen between late spring and autumn. Fin whales appeared to occur year-round. These increases are consistent with gradual recovery, though increased observation efforts may also contribute.

Despite these signs of recovery, large whales still face threats. These include ship strikes, entanglement in fishing gear, underwater noise, pollution, and climate change. Researchers recommend expanding passive acoustic monitoring. They also suggest increasing trained observer coverage in commercial sectors. Incorporating whale distribution data into marine spatial planning is also advised. These measures can help safeguard the slow but important recovery of these species.