Diving behavior of the Atlantic walrus in high Arctic Greenland and Canada

Research output: Contribution to journalJournal articlepeer-review

  • Eva Garde
  • Signe Jung-Madsen
  • Ditlevsen, Susanne
  • Rikke G. Hansen
  • Karl B. Zinglersen
  • Mads Peter Heide-Jørgensen

Investigations of diving behavior of the Atlantic walrus (Odobenus rosmarus rosmarus) in the high Arctic Greenland and Canada are important for understanding behavioral adaptations and area utilization of this Arctic benthic feeder. Furthermore, such information along with estimations of annual consumption and carrying capacity of walruses are needed in management decisions of this utilized species. Satellite-linked transmitters deployed on 27 walruses from 2010 to 2013 provided data for investigations of diving behavior in three predefined main areas: NW Greenland, Smith Sound and NE Canada. Sub-areas within each main area were also compared. Depth of dives, dive rates, time at depth of dives, haul-out periods and vertical speeds were estimated. Majority of dives targeted depths from 10 to 100 m, which corresponds to the distribution of walrus preferred food items. Four dives to depths > 500 m occurred and are the deepest ever documented for a walrus. Dive rates and time at depth of dives were significantly different between sub-areas (p < 0.0001), whereas haul-out periods were not (p = 0.072). Mean vertical speeds to destination depths ranged from 1.0 m s− 1 (95% CI: 0.8–1.2) to 1.8 m s− 1 (95% CI: 1.0–2.6). Based on dive rates, time at depth, haul-out and percentage of feeding dives Alexandra Fjord and Princess Mary Bay in NE Canada and Carey Island in NW Greenland were identified as the most important areas for walrus feeding during summer. Walrus predation on the standing bivalve biomass in NW Greenland (within 5–100 m of depth) was estimated to 3.2% annually based on assessments of mean biomass of walrus preferred prey items. From a simple relationship between available shallow water habitat, current population size (n = 2544) and walrus pre-exploitation population sizes it is furthermore proposed that the carrying capacity in the Smith Sound region does not exceed 5000 walruses.

Original languageEnglish
JournalJournal of Experimental Marine Biology and Ecology
Volume500
Pages (from-to)89-99
Number of pages11
ISSN0022-0981
DOIs
Publication statusPublished - 1 Mar 2018

    Research areas

  • Diving behavior, benthic feeding, Marine mammals, Odobenus r. rosmarus, Satellite telemetry, Smith Sound

ID: 195194485