Each year, humpback whales (Megaptera novaeangliae) migrate thousands of kilometres from their Antarctic feeding grounds to the warmer waters of East Africa, where they breed, give birth and care for their calves. As the 2026 whale season begins in the Bazaruto Archipelago, the BCSS research team is once again documenting these remarkable visitors and contributing valuable data to the study of the East African humpback whale population.
Identifying Whales Through Their Flukes
During dedicated boat-based surveys, BCSS researchers photograph the underside of the fluke when a whale raises its tail before a deeper dive. Alongside each photograph, the team records information including the date, time, GPS position, group composition, behaviour and environmental conditions. Good-quality images can then be compared with previous BCSS records and uploaded to Happywhale, a global collaborative platform that matches individual whales across locations and years.
These matches can reveal whether a whale has returned to the Bazaruto Archipelago, where else it has been encountered and, occasionally, the extraordinary distances it has travelled. Over time, photo-identification helps researchers investigate humpback whale movements, site fidelity, population connectivity, migration routes and individual life histories without any physical contact with the animals.
Photo: Ekaterina Kalashnikova
Four Days, 63 Whales and 24 Flukes
A group of whale enthusiasts from Team Trip, led by marine enthusiast Pavel Fokin and well-known environmentalist Eugenia Timonova, recently joined BCSS researcher Ekaterina Kalashnikova for four dedicated humpback whale surveys.
Across the four days, the team recorded 63 whale sightings and successfully photographed 24 identifiable flukes. Every encounter was entered into the BCSS database together with its associated field data. Preliminary comparisons with the existing catalogue indicated that 23 flukes belonged to previously undocumented individuals, while one whale had been recorded before.
No two survey days were alike. Weather, visibility, wind speed and wind direction continually shaped both whale activity and the team’s ability to locate and document the animals. These changing conditions are an important part of field research: even when surveys follow the same protocol, every day at sea provides a different window into the lives of the whales.
Photo: Ekaterina Kalashnikova
Observing Humpback Whale Behaviour
The team witnessed repeated breaches, including calves appearing to practise or imitate the spectacular surface behaviour of their mothers. Although the precise functions of breaching are still being studied, it may play roles in communication, social interaction, physical development and play. For a young whale, observing and copying its mother may also be an important part of learning the behaviours needed later in life.
The surveys also encountered competitive groups of up to seven whales. These fast-moving, highly energetic groups typically form when several males compete for proximity to a female. Their interactions can involve rapid changes of direction, close physical contact, powerful surface displays, bubble trails and a variety of vocal and respiratory sounds.
Photo: Ekaterina Kalashnikova
The Unmistakable Sound of a Trumpeting Whale
Among the most memorable observations were several ‘trumpeting’ blows – extended, deep, resonant exhalations sometimes described as sounding like a trumpet or distant foghorn.
Unlike the ordinary explosive breath heard when a whale surfaces, a trumpet is a prolonged sound produced through the blowhole and audible above the water. Trumpeting has been documented as part of the humpback whale behavioural repertoire, including during socially active encounters. However, its exact meaning is not yet fully understood. Depending on the context, it may communicate excitement, agitation, exertion or social intent to nearby whales. Rather than assigning it one fixed interpretation, researchers document the sound together with the whale’s group composition and behaviour, allowing patterns to emerge across repeated observations.
Science Continuing After Sunset
The learning did not end when the research boat returned to shore. Each evening, Ekaterina and Eugenia delivered presentations and informal lectures covering a broad range of marine topics. These included the ecology of the Bazaruto seascape, cetaceans of the Western Indian Ocean, the biodiversity of Bazaruto’s coral reefs, humpback whale ecology, research conducted through the BCSS Ocean Observatory, shark conservation, deep-sea inhabitants and many other fascinating aspects of marine science.
This combination of direct field participation and evening learning sessions allowed the group to connect each observation at sea with the wider ecological and conservation context.
Naming the Whales
On the final day, participants reviewed the photographed flukes and gave the identified whales names inspired by their pigmentation, shapes, notches, scars and the personal associations evoked by their markings.
Several names reflected the group’s diverse cultural and artistic references. Malevich, Kandinsky and Pollock were named after celebrated artists whose distinctive visual styles seemed to echo the contrasting patterns and abstract markings on the whales’ flukes. Pushkin honoured one of Russia’s most renowned writers, while Samurai and Achilles, the legendary hero of Greek mythology, were inspired by history, literature and heroic traditions.
Other names described shapes or images that participants recognised in the markings. Kipepeo, meaning “butterfly” in Swahili, was chosen for a pattern resembling outstretched wings, while Moyo, the Swahili word for “heart”, reflected a heart-like marking. Pássaro, meaning “bird” in Portuguese, evoked the image of a bird in flight. Ulkan Ola, from the Uzbek language, can be translated as “large spotted”- a fitting description of that individual’s distinctive fluke.
Some names, including Venus, Marilyn, DrPepper, Inky, Freckled, Black Stitch, Zefir, Eagle and Marble, arose from colours, textures, familiar figures or spontaneous associations. Others – Lily, Belyash and Zefir – added a playful, affectionate character to the catalogue. Together, the names captured not only the whales’ physical individuality, but also the creativity, cultural backgrounds and shared experiences of the people who encountered them.
Although researchers ultimately catalogue every whale using a unique identification code, names make individuals easier to remember and help participants form a more personal connection with their stories. A fluke is no longer simply another photograph in a database: it belongs to an individual whale whose movements, encounters and possible return to Bazaruto can now be followed over time.
New Arrivals From Antarctic Waters
Several whales still carried patches of yellow-brown diatom film on their skin. Diatoms are microscopic algae that can accumulate on whales while they occupy cold waters around Antarctica. Warmer tropical waters promote skin renewal and the gradual shedding of both old skin cells and the attached diatoms. For this reason, visible diatom patches are consistent with whales having arrived relatively recently from high-latitude feeding grounds, although their presence alone cannot determine an exact arrival date.
These diatom-covered newcomers suggest that we are still near the beginning of the humpback whale season. During the coming two months, BCSS researchers will continue collecting photo-identification and behavioural data together with Scientific Training Program students, divers and other participants supporting the Ocean Observatory.
Photo: Inna Kopylova
What Happens to the New Fluke Photographs?
The next step is to prepare and upload the new fluke photographs to Happywhale, where they can be compared against records from across the Southern Hemisphere. Will any of Bazaruto’s newly named whales have already been photographed elsewhere along their migration route?
Watch this space for the official uploads – and, hopefully, some exciting matches.
Acknowledgements
BCSS gratefully acknowledges Ekaterina Kalashnikova, Rostislav Dormidontov and Uliana Kapitonova for capturing the photo-identification images during the surveys. Their photographs provide the essential visual records that allow individual whales to be identified, catalogued and compared across locations and years.
🔗 Humpback Whale Photo ID Expeditions
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For questions about this article, please contact:
Ekaterina Kalashnikova, Bazaruto Archipelago – Ocean Observatory Bazaruto Center for Scientific Studies ekaterina.kalashnikova@bcssmz.org
To get in touch and collaborate with our research Center , please visit https://bcssmz.org/logistical-support-consultancy/
To learn more about our Scientific Training Program, please see https://bcssmz.org/scientific-training-program/