Food chain without giants: Modelling the trophic impact of bowhead whaling on little auk populations in the Atlantic Arctic

• Main Authors: Thépault, Amaury, Rodrigues, Ana, Drago, Laetitia, Grémillet, David
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2024
• Subjects: Seabirds; Whales; deterministic modelling; ecological baseline; historical ecology; trophic niche; Alle alle; Atlantic Arctic; Atlantic-Arctic; Balaena mysticetus; Barents Sea; East Greenland; Greenland; Institut Polaire Français; little auk; Northeast Atlantic; Svalbard
• Online Access: https://doi.org/10.5281/zenodo.10593360

In the Atlantic Arctic, bowhead whales ( Balaena mysticetus ) were nearly exterminated by European whalers between the 17th and 19th centuries. The collapse of the East Greenland-Svalbard-Barents Sea population, from an estimated 50,000 to a few hundred individuals, drastically reduced predation on mesozooplankton. Here, we tested the hypothesis that this event strongly favoured the demography of the little auk ( Alle alle ), a zooplanktivorous feeder competitor of bowhead whales, and the most abundant seabird in the Arctic. To reconstruct pre-whaling little auk abundance, we modelled trophic niche overlap between the two species using deterministic simulations of mesozooplankton spatial distribution. We estimated a 70% increase in Northeast Atlantic Arctic little auk populations following bowhead whaling, from 2.8 million to 4.8 million breeding pairs. While corresponding to a major population increase, this is far less than predicted by previous studies. Our study illustrates a trophic shift resulting from the near extirpation of a marine megafauna species, and the methodological framework we developed opens up new opportunities for marine trophic modelling. Funding provided by: Institut Polaire Français Paul Émile Victor ROR ID: https://ror.org/011ed2d57 Award Number: