Humpback Whale Supergroups Return to South Africa’s Waters
Every year from June to November, humpback whales migrate along the South African coastline, feeding on the nutrient‑rich Benguela upwelling system. While sightings of small pods have long been routine, recent years have brought an extraordinary shift: massive gatherings—sometimes numbering in the hundreds—are becoming a regular spectacle.
A Photographer’s First‑Hand Account
Cape Town‑based wildlife photographer Chris Fallow first noticed the change in late 2023 while out on his research vessel.
“Initially we saw groups of 20, maybe even 50. But around mid‑December those groups grew to 100 and we knew something very special was coming,” he recalls.
By the end of December, about 100 km north of Cape Town, Fallow and his wife Monique observed what he described as “a Manhattan skyline of whale breath.” The pair spent hours documenting the event, photographing each whale’s fluke (tail) and uploading the images to the citizen‑science platform Happywhale. Their effort contributed to a record‑setting entry: 299 individual humpbacks identified in a single 24‑hour window—the largest aggregation ever logged on the platform.
Monique added a sensory note that often goes unmentioned: “They feed on krill, which is very fish‑like, and they’re constantly burping and farting. The smell was really overwhelming.”
Why Supergroups Are Forming Now
According to Dr. Els Vermeulen, senior scientist at the Whale Division of the University of Pretoria, the phenomenon is a direct outcome of population recovery.
- The International Whaling Commission (IWC) estimates that Southern Hemisphere humpback numbers have risen from roughly 10,000 in the mid‑1980s to about 100,000 today, following the 1986 global moratorium on commercial whaling.
- Vermeulen notes that the first documented supergroups appeared around 2012, coinciding with the point when the population had rebounded enough to sustain dense feeding aggregations.
- Humpbacks use low‑frequency vocalizations to signal the location of dense krill patches. As more individuals succeed in finding food, these calls attract additional whales, creating a positive feedback loop that fuels supergroup formation.
The Benguela upwelling—driven by cold, nutrient‑rich waters rising along the southwest coast—provides the high‑productivity environment that makes such gatherings possible.
Conservation Challenges Amid Recovery
While the resurgence of humpbacks is a conservation success story, it brings new risks, particularly from vessel traffic.
- A preliminary assessment co‑authored by Vermeulen indicates that the number of fast‑moving ships transiting South Africa’s southwest coast has quadrupled since December 2023, partly due to rerouting caused by the Middle East conflict.
- Ship strikes remain a leading cause of mortality for large whales. Because most struck whales sink, official statistics are scarce; however, carcasses that wash ashore often show clear propeller injuries, as noted by Gregg Oelofse, coastal and environmental manager for the City of Cape Town.
- Humpbacks are less vigilant while feeding, making them especially vulnerable in the coastal zones where supergroups congregate.
Vermeulen is working with the shipping industry to develop mitigation strategies, such as voluntary speed reductions near key ports like Saldanha Bay and Cape Town. Currently, South Africa has no mandatory speed‑limit regulations aimed at protecting whales, a gap that experts urge policymakers to address.
Looking Ahead
The return of humpback whale supergroups offers a vivid reminder of marine ecosystems’ capacity to heal when given protection. Continued monitoring—through platforms like Happywhale, scientific surveys, and community observer programs—will be essential to track population trends and assess the effectiveness of mitigation measures. Balancing the awe‑inspiring sight of these giants with the realities of increased maritime activity will determine whether future generations can still witness the “Manhattan skyline” of whale breath along South Africa’s shores.
