The Effects of Climate Change on Humpback Whales (Megaptera novaeangliae): A Review of Current Knowledge

Anthropogenic climate change is transforming marine ecosystems at an unprece-dented rate, significantly affecting large migratory species, such as the humpback whale (Megaptera novaeangliae). Humpback whales, as other species of baleen whales, require high amount of food resources, and are dependent on productive feeding grounds and environmental cues, providing valuable insights into ecolog-ical responses to oceanic changes. This systematic literature review synthesised 39 peer-reviewed studies published from 2000 to 2025 to examine the effects of climate-related environmental changes on humpback whale ecology across glob-al ocean basins. The literature review revealed that rising sea surface tempera-tures (SST), sea ice variability, and significant climatic oscillations (ENSO, SAM, IOD, PDO, NPGO) constitute over two-thirds of all recorded climate ef-fects affecting the species. These effects were mostly associated with alterations in whale distribution, prey availability, and reproductive success. They have also been associated with changes in migration patterns and abundance. Correspond-ence analysis confirmed that long-term warming (rising SST) demonstrates a strong link with distributional shifts, whereas short-term heating extremes (ma-rine heatwaves) mostly influence abundance and reproductive success. The spa-tial research coverage was broad but effort distribution was highly unbalanced. Most studies were focused on the Southern Ocean and North Pacific, whereas the Indian, Atlantic, and Arctic Oceans received less study effort. Distinct regional patterns were evident, with alterations in sea ice impacting the Southern Hemi-sphere populations and marine heatwaves significantly influencing the popula-tion of humpback whales in the North Pacific. These findings highlight the vary-ing sensitivity to climate change of different humpback whale populations around the globe. They emphasise the need for spatially comprehensive evidence to assess vulnerability and inform future initiatives.