In a striking example of how climate change is reshaping marine life, scientists have found that whales are adapting to warming oceans by altering what they eat and how they share food resources. The findings, based on nearly three decades of data, suggest that rising sea temperatures and shrinking prey availability are forcing whales to adjust their feeding strategies in ways not seen for decades.
The study highlights how climate change is not only warming the oceans but also reshaping marine food webs and ecosystem dynamics, with long-term consequences for ocean health.
Long-Term Study Reveals Shifting Feeding Patterns
The research, published in Frontiers in Marine Science analysed more than 1,100 tissue samples from fin, humpback and minke whales collected over 28 years in the Gulf of St. Lawrence, a key seasonal feeding ground in the North Atlantic. Scientists used stable isotope analysis to trace how whale diets have evolved as ocean temperatures increased and ice conditions changed.
According to lead author Charlotte Tessier-Larivière of the Maurice Lamontagne Institute, whales are increasingly dividing food resources differently as competition grows. As Arctic krill becomes less available, fin and minke whales are relying more heavily on pelagic fish, turning species like capelin, herring, mackerel and sand lance into shared prey across whale populations.
Adapting to Scarcer Prey in Warmer Oceans
Historically, fin whales in the 1990s fed primarily on krill, which thrives in colder waters. However, the study shows that as krill populations declined, fin, humpback and minke whales shifted toward fish-based diets. The overlap between species diets has also changed, suggesting a gradual rebalancing of feeding niches as food sources become scarcer and more unevenly distributed.
Scientists say these changes reflect how whales, as top predators, are responding to environmental stress. Because whales sit at the top of the marine food chain, shifts in their feeding behaviour serve as warning signs of deeper changes in ocean ecosystems.
Researchers note that documenting nearly 30 years of feeding behaviour offers a rare window into how large marine species are coping with climate-driven disruptions. The study underscores that climate change is not a distant threat but an active force reshaping life in the oceans today.