Some like it cold: Temperature-dependent habitat selection by narwhals.

Autor: Heide-Jørgensen MP; Greenland Institute of Natural Resources Copenhagen Denmark., Blackwell SB; Greeneridge Sciences Inc. Santa Barbara CA USA., Williams TM; Center for Ocean Health - Long Marine Laboratory University of California-Santa Cruz Santa Cruz CA USA., Sinding MHS; Greenland Institute of Natural Resources Copenhagen Denmark.; Smurfit Institute of Genetics Trinity College Dublin Dublin Ireland., Skovrind M; GLOBE Institute University of Copenhagen Copenhagen Denmark., Tervo OM; Greenland Institute of Natural Resources Copenhagen Denmark., Garde E; Greenland Institute of Natural Resources Copenhagen Denmark., Hansen RG; Greenland Institute of Natural Resources Copenhagen Denmark., Nielsen NH; Greenland Institute of Natural Resources Nuuk Greenland., Ngô MC; Greenland Institute of Natural Resources Copenhagen Denmark., Ditlevsen S; Data Science Laboratory Department of Mathematical Sciences University of Copenhagen Copenhagen Denmark.
Jazyk: angličtina
Zdroj: Ecology and evolution [Ecol Evol] 2020 Jul 22; Vol. 10 (15), pp. 8073-8090. Date of Electronic Publication: 2020 Jul 22 (Print Publication: 2020).
DOI: 10.1002/ece3.6464
Abstrakt: 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.
Competing Interests: There are no competing interests.
(© 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
Externí odkaz: