Winter Brings the Giants
Winter in the Southern Hemisphere signals more than just cooler days and windier conditions — it marks the return of some of the ocean’s greatest travelers. Each year, humpback whales and other cetaceans move along Africa’s coastline, transforming Mozambique’s waters into a living stage of migration. This whale migration Mozambique is one of the most spectacular natural events in the Indian Ocean. Mothers guide newborn calves through sheltered bays, males perform acrobatic breaches and tail slaps, and entire groups pass through the Mozambique Channel on their way to breeding grounds.
From the shoreline of Benguerra Island, the Bazaruto Center for Scientific Studies (BCSS) stands as a frontline observer of this seasonal phenomenon. Through its Ocean Observatory, BCSS documents movements, behaviors, and population patterns, helping to build a clearer picture of whale migration across the Western Indian Ocean.
Humpback whales spotted from a BCSS research boat during migration — image by Daniel Escayola.
What Species Are Migrating?
The main highlight of Mozambique’s whale season is the annual movement of Indian Ocean humpback whales (Megaptera novaeangliae). Known for their dramatic acrobatics and haunting songs, humpbacks are among the most studied of all migrating whales globally — yet mysteries remain about their precise routes and behaviors in the Western Indian Ocean.
Beyond humpbacks, Mozambique occasionally welcomes other migratory giants. Bryde’s whales (Balaenoptera edeniare) are sometimes observed further offshore, and rare sightings of blue whales (Balaenoptera musculus) — the largest animals ever to exist — have been recorded in nearby regions of the Indian Ocean. Pods of spinner dolphins, bottlenose dolphins and other cetaceans are often seen alongside these leviathans, adding to the richness of Mozambique’s marine life.
Where Do They Come From and Where Do They Go?
The migration story begins thousands of kilometers south, in the nutrient-rich feeding grounds of Antarctica and the sub-Antarctic islands. Here, whales gorge on krill and schooling fish during the austral summer, storing the energy they’ll need for long journeys.
As winter approaches, humpbacks and other species turn north. They navigate through the Indian Ocean basin, heading toward warmer waters to breed and calve. Coastal regions of Kenya, Mozambique, Madagascar, Tanzania, Mascarene and other oceanic Islands of the region provide sheltered, relatively predator-free zones where mothers can give birth and raise young calves before making the long return trip south.
This cycle is part of the broader WIO whale migration — a remarkable seasonal movement that links the icy Southern Ocean to the tropics of East Africa and broader WIO region. Understanding these routes is vital for conservation, as whales face challenges from shipping traffic, entanglement, and shifting ocean conditions linked to climate change, amongst other threats
Mozambique Channel as a Highway
The Bazaruto Archipelago sits at the heart of this migratory route. Shaped by underwater canyons, shifting currents, and productive upwellings, the Mozambique Channel functions as a marine highway for traveling whales.
From the BCSS station on Benguerra Island, researchers regularly record Bazaruto whale sightings during the autumn and winter months. It’s common to observe competitive male groups, tail-slapping displays, and breaching behaviors. Mothers with calves are also seen close to shore, taking advantage of calmer waters.
This natural corridor emphasizes why Mozambique is considered one of the best whale-watching regions in the Western Indian Ocean. By studying this passage, scientists can learn more about how physical geography and ocean temperature shifts influence whale behavior.
A humpback whale gliding through the water during migration.
How BCSS Tracks and Observes Whale Migration
Documenting whale movements requires a mix of science, technology, and collaboration. BCSS uses several complementary methods to build seasonal records:
- Visual surveys from boats and land stations
- Acoustic monitoring with hydrophones to detect whale song and other vocalizations
- Photographic identification, especially fluke (tail) patterns
- Citizen science reports, where local divers, fishermen, and tourists share sightings
This integrated approach ensures that the migration is observed in real time while also building long-term datasets for analysis. Through the Ocean Observatory, data are archived and shared openly, strengthening the collective knowledge of the region.
This process forms the backbone of BCSS whale monitoring, ensuring that Mozambique’s migration patterns contribute to global understanding of this species’ ecology.
Western Indian Ocean Migration Patterns
Compared to regions like the North Atlantic or Pacific, the Western Indian Ocean remains one of the least studied whale migration corridors. Limited historical data, fragmented monitoring efforts, combined with vast stretches of open ocean mean that much about these populations remains unknown.
Recent collaborations — including partnerships with platforms like Happywhale — are helping fill knowledge gaps. Photo-ID databases and satellite tagging projects are connecting humpback populations across the region. This transboundary research reveals that whales do not adhere to national borders — they rely on the health of the entire basin.
The WIO whale migration is therefore not only an ecological marvel but also a call for regional cooperation. Without shared data and long-term monitoring, understanding and protecting these populations would be nearly impossible.
A humpback whale mother guides her calf through the waters off Mozambique — a vital stage in the annual whale migration.
Winter Sightings and Seasonality
Every winter, as waters cool and winds shift, the migration season begins. In Mozambique, whales are typically sighted between June and November, with peak activity during August and September. This window forms the heart of the whale season, when visitors and researchers alike have the best chance of observing them.
Typical behaviors during this time include breaching, tail and pectoral slapping, head lunges, spy hopping, and fluking, — often associated with communication and mating displays. Calves, born in tropical waters earlier in the season, can be seen building strength before their first long journey back to Antarctica.
These observations not only inspire awe but also provide essential data. Tracking how long whales stay, what behaviors they display, and when they leave helps scientists understand broader shifts in ocean conditions and climate.
How Readers Can Help
The story of whale migration isn’t just written by scientists — it’s a collective effort. Anyone who encounters a whale in Mozambique or across the Indian Ocean can contribute to research in meaningful ways:
- Submit photos of whale flukes to global platforms like Happywhale, where they are matched to individuals in ID databases.
- Share sightings with BCSS, adding to seasonal monitoring records.
- Join citizen science opportunities, such as marine expeditions, scientific dive trips, or the Scientific Training Program.
Even spreading awareness about these migrations helps build momentum for protecting them. Every action adds to a growing network of conservation-minded observers.
A Season of Giants
The return of humpbacks and other cetaceans each year is more than a natural spectacle — it is a reminder of the resilience and rhythm of the ocean. As they arrive and pass through Mozambique’s waters, these whales connect ecosystems across continents, linking the icy south to the tropical north.
At BCSS, documenting and sharing this migration is part of a broader mission: to protect fragile ecosystems through science, collaboration, and education. By following the migration, sharing sightings, or supporting research, readers become part of this story too.
Annual migration is here. From breaching giants to new whale calves, this season is full of magic and meaning.
→ Explore the Ocean Observatory and follow the migration in real time
DOI Link: https://doi.org/10.82174
/bcssmz.article.understanding.whale.migration.mozambique
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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/