Unraveling the mysteries of the killer whale diet and its role in climate change
Killer whale populations are invading the Arctic, causing major disruption in an ecosystem already severely affected by climate change. A team of researchers from McGill University have found new clues to understanding how killer whales affect their environment – by reconstructing their diet using the lipids in their blubber.
“This analysis will help us better understand how their diets are changing and how they might disrupt Arctic food webs,” said Anaïs Remili, a PhD student in the McGill Department of Natural Resource Sciences and lead author of the study.
To reconstruct the whales’ diet, the researchers used a model called Quantitative Fatty Acid Signature Analysis (QFASA) using samples from captive killer whales. Then they measured the fat acid Composition of wild Greenland killer whales and potential prey species the whales might feed on. Finally, they applied the modeling approach to estimate that the whales feed primarily on harp seals and hooded seals, species that researchers have found in some of the whales’ stomachs.
This new tool has the potential to improve understanding of orca diets around the world and show how orca might impact Arctic food webs in the future.
Reference: “Validation of Quantitative Fatty Acid Signature Analysis to Estimate Diet Composition of Free-Ranging Killer Whales” by Anaïs Remili, Rune Dietz, Christian Sonne, Sara J. Iverson, Denis Roy, Aqqalu Rosing-Asvid, Haley Land-Miller, Adam F. Pedersen, and Melissa A .McKinney, 13 May 2022, Scientific Reports.