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Rune Dietz

The impact of rising sea temperatures on an Arctic top predator, the narwhal

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review

DOI

  • P. Chambault, Greenland Institute of Natural Resources
  • ,
  • O. M. Tervo, Greenland Institute of Natural Resources
  • ,
  • E. Garde, Greenland Institute of Natural Resources
  • ,
  • R. G. Hansen, Greenland Institute of Natural Resources
  • ,
  • S. B. Blackwell, Greeneridge Sciences, Inc.
  • ,
  • T. M. Williams, University of California at Santa Cruz
  • ,
  • R. Dietz
  • C. M. Albertsen, DTU Aqua
  • ,
  • K. L. Laidre, University of Washington
  • ,
  • N. H. Nielsen, Greenland Institute of Natural Resources
  • ,
  • P. Richard, Fisheries and Oceans Canada
  • ,
  • M. H.S. Sinding, Greenland Institute of Natural Resources, Trinity College Dublin
  • ,
  • H. C. Schmidt, Greenland Institute of Natural Resources
  • ,
  • M. P. Heide-Jørgensen, Greenland Institute of Natural Resources

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.

OriginalsprogEngelsk
Artikelnummer18678
TidsskriftScientific Reports
Vol/bind10
ISSN2045-2322
DOI
StatusUdgivet - okt. 2020

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