First documented observation of feeding behaviour of humpback whales (Megaptera novaeangliae) in its breeding range off the southern coast of Tanzania

Feeding and breeding activities of humpback whales (Megaptera novaeangliae) are generally understood to be geographically and temporally separated, with feeding activities taking places in the higher latitudes and breeding in lower latitudes. However, humpback whales may supplement their energy budgets by feeding outside of their polar foraging grounds, with opportunistic feeding behaviour being observed in mid-to-low latitudes globally. The records of supplementary feeding during migration in the southern hemisphere have been documented for various breeding stocks, with no records for the East African stock. We present the first to our knowledge record of the humpback whales feeding events in the coastal waters of Tanzania, that have been recorded on the dedicated boat surveys conducted during the humpback whales breeding seasons in 2023 and 2024 off Mnazi Bay in Mtwara region. Demonstrated behavioural plasticity may play an important role in adaptation strategies to global environmental changes and prey availability fluctuations, all of which affect recovering populations. Mnazi Bay seascape and its vicinity is an important habitat for at least 11 species of cetaceans documented, all of which depend on its productive waters for foraging, socializing and as a nursery for migrating humpback whales. This record underpins the importance of the protection of this habitat. However, future studies are needed to confirm and understand the details of the observed supplementary feeding behaviour of the humpback whales and the potential reasons behind its occurrence in Tanzania.