Multi-decadal trends in biomarkers in harp seal teeth from the North Atlantic reveal the influence of prey availability on seal trophic position.

Arctic food webs are being impacted by borealisation and environmental change. To quantify the impact of these multiple forcings, it is crucial to accurately determine the temporal change in key ecosystem metrics, such as trophic position of top predators. Here, we measured stable nitrogen isotopes...

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Bibliographic Details
Published in:Global Change Biology
Main Authors: de la Vega, Camille, Kershaw, Joanna, Stenson, Garry B, Frie, Anne Kirstine, Biuw, Martin, Haug, Tore, Norman, Louisa, Mahaffey, Claire, Smout, Sophie, Jeffreys, Rachel M
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2023
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Online Access:http://livrepository.liverpool.ac.uk/3171715/
https://doi.org/10.1111/gcb.16889
http://livrepository.liverpool.ac.uk/3171715/1/GCB_delavega_accepted_05072023.pdf
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Summary:Arctic food webs are being impacted by borealisation and environmental change. To quantify the impact of these multiple forcings, it is crucial to accurately determine the temporal change in key ecosystem metrics, such as trophic position of top predators. Here, we measured stable nitrogen isotopes (δ 15 N) in amino acids in harp seal teeth from across the North Atlantic spanning a period of 60 years to robustly assess multi-decadal trends in harp seal trophic position, accounting for changes in δ 15 N at the base of the food web. We reveal long-term variations in trophic position of harp seals which are likely to reflect fluctuations in prey availability, specifically fish- or invertebrate-dominated diets. We show that the temporal trends in harp seal trophic position differ between the Northwest Atlantic, Greenland Sea and Barents Sea, suggesting divergent changes in each local ecosystem. Our results provide invaluable data for population dynamic and ecotoxicology studies.