Commercial whaling killed 350,000 blue whales; the giants are slowly returning

Commercial whaling decimated blue whale populations in the 20th century, killing an estimated 350,000 individuals, according to a new study. Despite the cessation of commercial hunting over four decades ago, blue and fin whales are beginning to return to parts of their historic range in the southeast Atlantic. Researchers have observed a marked rise in sightings, suggesting a slow but measurable recovery of these massive marine mammals. The findings come from a comprehensive analysis published in the African Journal of Marine Science, which reviewed more than six decades of confirmed whale records from the waters off Namibia and South Africa’s west coast. The study, led by Dr. Bridget James from the Centre for Statistics in Ecology, Environment and Conservation at the University of Cape Town, highlights a significant uptick in whale sightings, with 95 percent of all recorded observations occurring since 2012. Dr. Simon Elwen, a co-author and director of Sea Search, emphasized that the data provides crucial evidence of the species' gradual rebound following the near-extinction caused by commercial whaling. The research focused on the Benguela upwelling system, a nutrient-rich coastal region stretching along the western coast of southern Africa. Between 1964 and early 2025, scientists documented 12 confirmed blue whale sightings, one stranding, and five additional historical records. Fin whales fared slightly better, with 76 sightings and six strandings recorded. Seasonal patterns also emerged, with blue whales primarily sighted from late spring through autumn, whereas fin whales were observed throughout the year. Despite the positive trends, both species remain far below their historical population levels. Antarctic blue whales, currently listed as “Critically Endangered” by the International Union for Conservation of Nature (IUCN), have only reached approximately 3 percent of their pre-whaling numbers. However, their populations are growing annually by an estimated 5 to 8 percent. Fin whales, categorized as “Vulnerable” by the IUCN, have recovered to more than 30 percent of their original population size, with annual growth rates of around 4 to 5 percent. Scientists suggest that as these populations expand, the whales will likely begin to reoccupy regions they once inhabited. Dr. Elwen noted that the increased sightings and strandings align with this expectation. He added that improved monitoring efforts, including the presence of more observational vessels such as commercial seismic survey ships searching for oil and gas, might contribute to the apparent rise in sightings. However, challenges persist in accurately assessing the true state of whale populations. Limited long-term monitoring systems along the southwestern African coast make it difficult to determine exact population figures or the pace of recovery. Without consistent and systematic tracking, it remains unclear how swiftly these species will fully restore their former ranges. The study underscores the importance of continued conservation efforts and enhanced monitoring programs to support the ongoing recovery of blue and fin whales. Researchers stress that while the current data indicates progress, sustained protection measures are essential to ensure the survival and resurgence of these iconic marine giants.