It’s Humpback Soup: The Southern Ocean’s Most Extraordinary Comeback

Standing on the deck of the expedition vessel MV Plancius, while manoeuvring through the Gerlache Strait and watching whale after whale surface within the same stretch of water, Billy Heaney described the scene in real time as “humpback soup,” an authentic moment of observation rather than invention.

Since then, the phrase has resurfaced numerous times in other broadcasters' social feeds from the Antarctic setting, each instance pointing to the same underlying reality: that humpback whale encounters are no longer occasional highlights but now defining features of the journey south.

“The Gerlache Strait felt alive that day.” Said Billy when we talked to him about this story.

“The sun was shining, icebergs were drifting past the ship, snow-covered mountains towered in the distance, and everywhere I looked, there were the blows, backs, and flukes of humpback whales.

It really was ‘whale soup’, and I quickly lost count of the number of humpbacks that were congregating in that narrow stretch of water that separates the Antarctic Peninsula from the Palmer Archipelago. Or as I now like to call it, humpback alley.

Watching humpback whales feeding in these nutrient‑rich Antarctic waters is hands down, one of the best whale watching experiences of my life.”

This is why these encounters are cutting through and resonating on everyday social media feeds, meaning you don’t have to share a network with adventure travellers or scientists to see moving footage of dense whale aggregations dropped into your feed by your algorithm.

Yes, these 'wildlife encounter' clips are now also plagued by AI slop, but the genuine ones still routinely reach hundreds of thousands of viewers on platforms like Instagram and TikTok, and they prove that AI is simply not required when presenting such encounters. They are powerful and moving enough without it.  

This is not because of spectacle, but rather because whales occupy a rare emotional space in the human imagination, as brilliantly explored by ocean writer Melissa Hobson in her ExplorEarth feature, A Whale of a Time. The connection is both instinctive and enduring, rooted in scale, intelligence, and a sense of shared presence that very few other species evoke.

What the “humpback soup” encounter represents, however, extends beyond virality. The phrase has emerged from repeated field observations across the Antarctic Peninsula, where whale density during peak feeding periods can reach levels that feel spatially overwhelming. Multiple individuals surface, feed, and dive within the same confined area, creating an ocean surface that appears in near-constant motion.

The Southern Ocean was once the global centre of industrial whaling. Data compiled by the International Whaling Commission indicates that approximately two million whales were killed in Antarctic waters during the twentieth century, with populations of species such as the Humpback whale reduced by more than 90 per cent prior to the introduction of the commercial whaling moratorium in 1986.

Since that point, long-term monitoring and peer-reviewed research have documented sustained recovery. Assessments referenced by the International Whaling Commission and published in journals including Marine Ecology Progress Series show annual population growth rates of roughly 8 to 10 per cent for several Southern Hemisphere humpback populations. A 2020 synthesis of population data concluded that some breeding stocks in the South Atlantic sector have recovered to more than 90 per cent of their estimated pre-exploitation levels.

These figures are increasingly reflected in the density of whales observed in Antarctic feeding grounds, particularly along the western Antarctic Peninsula, where expedition vessels now encounter multiple individuals or groups within relatively confined areas.

The ecological basis for this recovery lies in Antarctic krill, a keystone species whose biomass has been estimated at several hundred million tonnes by the Scientific Committee on Antarctic Research and the Commission for the Conservation of Antarctic Marine Living Resources. These dense swarms underpin one of the most productive marine ecosystems on Earth.

As whale populations have increased, researchers have documented changes in feeding behaviour and aggregation patterns. Studies published in Frontiers in Marine Science and Nature describe more frequent cooperative feeding strategies, including bubble-net feeding, as well as multi-species feeding events in which humpback whales, minke whales, and seabirds exploit the same krill concentrations.

Whales also contribute to ecosystem productivity through nutrient cycling. Scientific work on the “whale pump” has shown that iron-rich whale waste enhances phytoplankton growth, reinforcing the base of the food web and contributing to a positive feedback loop that supports further biological productivity.

Under favourable environmental conditions, including stable water columns and concentrated prey, these processes can result in extremely high predator densities, producing the conditions so perfectly described as “whale soup.”

If whale recovery is the visible story, krill is the invisible one, representing both recovery and threat. 

Antarctic krill underpin the entire Southern Ocean ecosystem, forming the primary food source for whales, seals, and seabirds. Their biomass, estimated at hundreds of millions of tonnes by the Commission for the Conservation of Antarctic Marine Living Resources and the Scientific Committee on Antarctic Research, enables large-scale whale feeding events.

Krill fishing in Antarctica is legal, regulated, and tightly managed under CCAMLR, with annual catch limits currently set well below estimated total biomass. In recent years, reported catches have typically ranged between 300,000 and 500,000 tonnes annually, primarily concentrated around the Antarctic Peninsula, which is also one of the most important feeding grounds for recovering whale populations.

However, the issue is not only total volume, but concentration. Scientific concern has increasingly focused on the spatial overlap between krill fisheries and predator feeding zones. When fishing activity clusters in the same areas where whales, penguins, and seals rely on dense krill swarms, localised depletion can occur even if overall catch limits are not exceeded.

Alongside legal fishing, there are ongoing concerns around Illegal, Unreported and Unregulated (IUU) activity in the Southern Ocean, although this is considered far more prevalent in finfish fisheries than in krill. Even so, monitoring such a vast and remote region remains a persistent challenge, and enforcement relies on international cooperation, satellite tracking, and vessel reporting systems. This topic was brilliantly explored by broadcaster and producer Saunders Carmichael-Brown in his ExplorEarth story: ‘Krill: The Planet's Smallest Influencers?’

Climate change compounds this pressure. Krill depend on sea ice for parts of their life cycle, particularly during early developmental stages. Research highlighted by the Intergovernmental Panel on Climate Change shows that shifting sea ice patterns are already affecting krill distribution, which in turn influences where whales can feed.

The result is a system under multiple, overlapping stresses. Whale populations may be recovering, but the stability of that recovery is directly tied to the availability of krill, and that availability is no longer guaranteed.

In that context, “humpback soup” becomes more than a moment of abundance; it becomes a signal of a system that is working, but not without limits.

For expedition travellers, this recovery is experienced not as data, but as life-affirming encounters. Observational records maintained by operators working within the framework of the International Association of Antarctica Tour Operators (IAATO) indicate an increase in whale sightings per voyage in parts of the Antarctic Peninsula over the past decade. However, such observations remain dependent on environmental variability.

Zodiac excursions allow for low-impact observation in areas of active feeding, and whales often approach vessels without prompting, resulting in close-range encounters. Research published in Biological Conservation suggests that, when conducted under established guidelines, such encounters can occur without significant behavioural disturbance, although continued monitoring is necessary.

These encounters create a paradox in which they feel increasingly immediate yet remain governed by strict operational protocols designed to protect wildlife.

The recovery of whale populations in the Southern Ocean represents one of the clearest examples of effective international conservation policy. However, it exists within a system that is subject to ongoing environmental and economic pressures.

Krill fisheries, managed under the authority of the Commission for the Conservation of Antarctic Marine Living Resources, have expanded in recent years, with annual catches reaching several hundred thousand tonnes. Scientific guidance emphasises the need for precautionary management, particularly in regions where krill availability directly affects recovering whale populations and other predators.

At the same time, climate-driven changes in sea ice extent are altering krill habitat. Research published in Nature Climate Change and assessments by the Intergovernmental Panel on Climate Change indicate that shifts in sea ice patterns could have cascading effects across the Antarctic food web, with potential implications for the long-term stability of whale recovery.

The result is a conservation success story that remains contingent on broader environmental stability. Antarctica is often framed as a static wilderness, but the return of whales at scale underscores its dynamic nature. Long-term datasets, satellite tracking, and field observations through citizen science projects like HappyWhale all indicate that whales are once again significant ecological agents in the Southern Ocean, influencing nutrient cycles, prey dynamics, and ecosystem structure.

For expedition travellers, this translates into encounters that reflect not only the presence of wildlife but the re-emergence of ecological processes that had been suppressed for much of the twentieth century.