The Fight of Whales for Food in a Warming World

Researchers at Griffith University have predicted that the diets of humpback whales in the southern hemisphere could be significantly impacted by future climate change, They analyzes the dietary habits of these marine giants and the challenges they might face.
In their study, the researchers collected humpback whale blubber and skin samples in August and September 2019 in or near their respective breeding grounds off Brazil, Western and Eastern Australia, New Caledonia, and Colombia. They also collected krill samples from feeding grounds onboard three different vessels between January and March 2019.
Researchers found that despite distinct differences in the biochemical profiles among the populations, the diet of all tested humpback whale populations was Antarctic krill. This diet is rich in fat, which is essential for the whales’ migratory lifestyle.
The migratory lifestyle of humpback whales requires predictable ecosystem productivity, and so, we can expect that populations feeding in areas that are subject to the strongest climate change impacts are more likely to show the first signs of a departure from their high-fidelity krill diet.
At present, there is no evidence of a divergence from a high-fidelity krill diet, but the characteristic isotopic signal we discovered of whales feeding in productive upwelling areas or in the marginal sea-ice zone, implies that future reductions in sea-ice extent and duration, and rising ocean temperatures could impact their feeding ecology.
Researchers emphasized the importance of this study, explaining that the confirmation that each whale population follows a high-fidelity Antarctic krill diet could be used as baseline knowledge to assess the extent of climate change impacts in the feeding grounds in future studies.