Some like it cold: Temperature‐dependent habitat selection by narwhals

Ecology and Evolution

Terrie M. Williams¹  Susanne Ditlevsen²  Mikkel Skovrind³  Susanna B. Blackwell⁴  Rikke G. Hansen⁵  Eva Garde⁵  Mạnh Cường Ngô⁵  Mikkel Holger S. Sinding⁵  Mads Peter Heide‐Jørgensen⁵  Outi M. Tervo⁵  Nynne H. Nielsen⁶ 

[1] Center for Ocean Health – Long Marine Laboratory University of California‐Santa Cruz Santa Cruz CA USA;Data Science Laboratory Department of Mathematical Sciences University of Copenhagen Copenhagen Denmark;GLOBE Institute University of Copenhagen Copenhagen Denmark;Greeneridge Sciences Inc. Santa Barbara CA USA;Greenland Institute of Natural Resources Copenhagen Denmark;Greenland Institute of Natural Resources Nuuk Greenland;

关键词: buzzing;    deep diving;    East Greenland;    high Arctic;    oceanography;    satellite tracking;   

DOI  :  10.1002/ece3.6464

来源: DOAJ

【 摘 要 】

Abstract The narwhal (Monodon monoceros) is a high‐Arctic species inhabiting areas that are experiencing increases in sea temperatures, which together with reduction in sea ice are expected to modify the niches of several Arctic marine apex predators. The Scoresby Sound fjord complex in East Greenland is the summer residence for an isolated population of narwhals. The movements of 12 whales instrumented with Fastloc‐GPS transmitters were studied during summer in Scoresby Sound and at their offshore winter ground in 2017–2019. An additional four narwhals provided detailed hydrographic profiles on both summer and winter grounds. Data on diving of the whales were obtained from 20 satellite‐linked time‐depth recorders and 16 Acousonde™ recorders that also provided information on the temperature and depth of buzzes. In summer, the foraging whales targeted depths between 300 and 850 m where the preferred areas visited by the whales had temperatures ranging between 0.6 and 1.5°C (mean = 1.1°C, SD = 0.22). The highest probability of buzzing activity during summer was at a temperature of 0.7°C and at depths > 300 m. The whales targeted similar depths at their offshore winter ground where the temperature was slightly higher (range: 0.7–1.7°C, mean = 1.3°C, SD = 0.29). Both the probability of buzzing events and the spatial distribution of the whales in both seasons demonstrated a preferential selection of cold water. This was particularly pronounced in winter where cold coastal water was selected and warm Atlantic water farther offshore was avoided. It is unknown if the small temperature niche of whales while feeding is because prey is concentrated at these temperature gradients and is easier to capture at low temperatures, or because there are limitations in the thermoregulation of the whales. In any case, the small niche requirements together with their strong site fidelity emphasize the sensitivity of narwhals to changes in the thermal characteristics of their habitats.

【 授权许可】

Unknown