Humpback whale (Ekaterina Kalashnikova/BCSS)
The study, led by BCSS’ Ekaterina Kalashnikova, Mnazi Bay Ruvuma Estuary Marine Park’s Davis Godfrey Orio, and DMAD-Marine Mammals Research Association’s Dr. Aylin Akkaya, documented the first record of supplementary feeding during humpbacks’ migration within the WIO region. Typically, humpback whales are found breeding in Tanzanian waters, with their main feeding grounds being distinctly located in high-latitude polar regions.
While it’s known that humpback whales may boost their energy reserves in mid to low latitudes globally during their migration outside their main polar feeding grounds, these findings nonetheless suggest a hitherto undocumented behavioural flexibility of these whales in the WIO region. In other words, these were the first supplementary feeding activity by humpback whales in East African waters ever recorded by scientists.
Humbback whale (Ekaterina Kalashnikova/BCSS)
The team of researchers first documented possible feeding in Tanzanian waters in the Mnazi Bay Ruvuma Estuary Marine Park seascape on two separate dates in August 2023. At least three whales repeatedly performed short vertical dives together with lateral and vertical lunge feeding techniques alongside tuna, birds, and other cetaceans. This behaviour is typical of gulp feeders such as humpback whales. Gulp feeders are filter-feeding whales that take in large mouthfuls of water filled with prey in a single, powerful gulp. After engulfing the water and prey, they close their mouths and use their baleen plates to filter out the water, trapping the food inside.
This feeding strategy is energy-intensive but highly effective for capturing large quantities of prey at once. These observations, supported by photographic evidence, indicate the presence of sufficient prey to justify such energy-intensive feeding. On one hand, it suggests high oceanographic productivity. On the other hand, it highlights the importance of humpback whales’ presence in enhancing productivity through nutrient dispersal, thereby supporting biodiversity and fish biomass that benefit local communities in the waters off the Southeast African coast.
Ceteacans (Ekaterina Kalashnikova/BCSS)
Given these findings, the southern waters of Tanzania and possibly Mozambique may potentially serve as an opportunistic feeding zone for migrating humpback whales. To learn more, further scientific inquiry is critical.
Located in the Bazaruto Archipelago, directly along the humpback whales’ migration route from July until October, BCSS provides the perfect launching point for further research into humpback whales and other marine mammals. Our research station provides technical, logistical and scientific support for researchers and students involved in field projects, surveys, or location scouting. Our team can train new researchers and assist in planning and leading scientific expeditions.
Humpback whale (Ekaterina Kalashnikova/BCSS)
We also offer our Scientific Training Program which allows students to hone their skills in scientific diving, study marine ecosystems, conduct scientific fieldwork, and learn from professional scientists and technical staff.
Our staff welcomes the opportunity to collaborate to further understand the frequency and extent of humpback whale feeding in this region as well as other aspects of the ecology of cetaceans. The findings of this study further underscore the need to protect the broader habitat and to support the biodiversity and ecosystem services it provides, vital to coastal communities.
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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/
