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Chambault P, Tervo OM, Garde E, Hansen RG, Blackwell SB, Williams TM, Dietz R, Albertsen CM, Laidre KL, Nielsen NH, Richard P, Sinding MHS, Schmidt HC, Heide-Jørgensen MP. The impact of rising sea temperatures on an Arctic top predator, the narwhal. Sci Rep 2020; 10:18678. [PMID: 33122802 PMCID: PMC7596713 DOI: 10.1038/s41598-020-75658-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 10/14/2020] [Indexed: 02/04/2023] Open
Abstract
Arctic top predators are expected to be impacted by increasing temperatures associated with climate change, but the relationship between increasing sea temperatures and population dynamics of Arctic cetaceans remains largely unexplored. Narwhals (Monodon monoceros) are considered to be among the most sensitive of Arctic endemic marine mammals to climate change due to their limited prey selection, strict migratory patterns and high site fidelity. In the context of climate change, we assume that the population dynamics of narwhals are partly influenced by changes in environmental conditions, with warm areas of increasing sea temperatures having lower abundance of narwhals. Using a unique large dataset of 144 satellite tracked narwhals, sea surface temperature (SST) data spanning 25 years (1993–2018) and narwhal abundance estimates from 17 localities, we (1) assessed the thermal exposure of this species, (2) investigated the SST trends at the summer foraging grounds, and (3) assessed the relationship between SST and abundance of narwhals. We showed a sharp SST increase in Northwest, Mideast and Southeast Greenland, whereas no change could be detected in the Canadian Arctic Archipelago (CAA) and in the Greenland Sea. The rising sea temperatures were correlated with the smallest narwhal abundance observed in the Mideast and Southeast Greenland (< 2000 individuals), where the mean summer sea temperatures were the highest (6.3 °C) compared to the cold waters of the CAA (0.7 °C) that were associated with the largest narwhal populations (> 40,000 individuals). These results support the hypothesis that warming ocean waters will restrict the habitat range of the narwhal, further suggesting that narwhals from Mideast and Southeast Greenland may be under pressure to abandon their traditional habitats due to ocean warming, and consequently either migrate further North or locally go extinct.
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Affiliation(s)
- P Chambault
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark.
| | - O M Tervo
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark
| | - E Garde
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark
| | - R G Hansen
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark
| | - S B Blackwell
- Greeneridge Sciences, Inc, 5266 Hollister Avenue, Suite 107, Santa Barbara, CA, 93111, USA
| | | | - R Dietz
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - C M Albertsen
- DTU Aqua, Technical University of Denmark, 2800, Kgs. Lyngby, DK, Denmark
| | - K L Laidre
- Applied Physics Laboratory, Polar Science Center, University of Washington, Seattle, WA, 98105-6698, USA
| | - N H Nielsen
- Greenland Institute of Natural Resources, Box 570, 3900, Nuuk, Greenland
| | - P Richard
- Fisheries and Oceans Canada, Winnipeg, MB, R3T 2N6, Canada
| | - M H S Sinding
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark.,Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - H C Schmidt
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark
| | - M P Heide-Jørgensen
- Greenland Institute of Natural Resources, Strandgade 91, 1401, Copenhagen, Denmark
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