Fatty acid proportions in North Atlantic killer whales from the Canadian Arctic to Arctic Norway (2008-2021) ...

• Main Authors: McKinney, Melissa, Remili, Anaïs, Borgå, Katrine, Dietz, Rune, Ferguson, Steven, Granquist, Sandra, Jourdain, Eve, Kettemer, Lisa, Kiszka, Jeremy, Matthews, Cory, Rikardsen, Audun, Rosing-Asvid, Aqqalu, Ruus, Anders, Samarra, Filipa, Sonne, Christian, Watt, Cortney
• Format: Dataset
• Language: unknown
• Published: Canadian Cryospheric Information Network 2023
• Subjects: Faroe Islands; Greenland; Iceland; Killer Whale; North Atlantic; Orca; Orcinus orca; Killer whale
• Online Access: https://dx.doi.org/10.21963/13299; https://www.polardata.ca/pdcsearch?doi_id=13299

Scientists have been studying the feeding habits of killer whales for decades, but there is still much to learn. Recent studies suggest that killer whales from Norway and Iceland mainly feed on fish, while those from Greenland and Canada eat marine mammals. Most of the previous studies that looked at North Atlantic killer whale diets relied on observation at sea. And while observing a predation event is always useful and indicates that a specific species have been consumed at some point, we cannot really conclude on the long-term dietary habits of various populations. This is especially true for remote populations (think the Canadian Arctic and Greenland), because these observation events cannot happen year-long. To better understand what these predators eat, scientists can use time-integrated dietary tracers like stable isotopes or fatty acid signature analysis. These methods provide information about a predator's long-term diet, especially when killer whales are in isolated areas and impossible to observe ... : Quantifying the diet composition of apex marine predators such as killer whales (Orcinus orca) is critical to assessing their food web impacts. Yet, with few exceptions, the feeding ecology of these apex predators remains poorly understood. Here, we use our newly validated quantitative fatty acid signature analysis (QFASA) approach on nearly 200 killer whales and 900 potential prey to model their diets across the 5,000 km span of the North Atlantic. Diet estimates show that killer whales mainly consume other whales in the western North Atlantic (Canadian Arctic, Eastern Canada), seals in the mid-North Atlantic (Greenland), and fish in the eastern North Atlantic (Iceland, Faroe Islands, Norway). Nonetheless, diet estimates also varied widely among individuals within most regions. This level of inter-individual feeding variation should be considered for future ecological studies focusing on North Atlantic killer whales. These estimates reveal remarkable population- and individual-level variation in the trophic ...