The Davis Strait - DCE - Nationalt Center for Miljø og Energi

70°N
60°N
50°N
75°W
120
120°W
105°W
90°W 75°W 60°W 45°W 30°W
60°W
15°W
0°
Deployment sites
Baffin Bay sub-pop.
45°W
70°N
60°N
Lancaster Sound sub-pop.
Kane Basin sub-pop.
Davis Strait sub-pop.
Assessment area
0 250 500 Km
50°N
70°N
60°N
50°N
75°W
120°W
90°W 75°W 60°W 45°W 30°W
A genetic study of polar bears (Paetkau et al. 1999) indicated significant differences
between bears from the Davis Strait and neighbouring Baffin Bay.
The Davis Strait subpopulation of polar bears range in the ‘seasonal-ice’
ecoregion (Amstrup et al. 2007, 2008), with the ice-free period extending
from approximately August through November. Annual ice cover in Davis
Strait is highly variable and ice breakup has become earlier since 1991
(Stirling & Parkinson 2006).
Satellite telemetry conducted in the period 1991-2001 showed that polar
bears from the DS subpopulation range the offshore pack ice in the Davis
Strait (Mosbech et al. 2007). The movement of the bears instrumented with
satellite-radios indicated an overall tendency to occur on the fast ice and in
the shear zone between fast ice and pack ice along eastern Baffin Island.
However, in December-June there is an overlap between the distribution of
some polar bears from the Davis Strait subpopulation and the assessment
area.
The extent of the pack ice in the Davis Strait varies from year to year (see
chapter 3). So does the position of the Davis Strait whelping patch of hooded
seals, Cystophora cristata (Bowen et al. 1987). During the period 1974-1984,
the location of this whelping patch where polar bears occur (F.O. Kapel, per-
105°W
60°W
15°W
0°
Movement, all year
Davis Strait sub-pop.
Baffin Bay sub-pop.
45°W
70°N
60°N
Lancaster Sound sub-pop.
Kane Basin sub-pop.
Assessment area
0 250 500 Km
Figure 4.8.1. Left: Locations where adult female polar bears were instrumented with satellite transmitters (1991-1995) given by
sub-population (Davis Strait, Baffin Bay, Lancaster Sound and Kane Basin). A total of 29 bears were instrumented in the Davis
Strait subpopulation (blue) and their movements tracked during 1991-2001. The identification and delineation of the various subpopulations
based on hierarchal cluster analyses is described in Taylor et al. (2001). Unpublished data: Nunavut Wildlife Management
Division, University of Saskatchewan, Canadian Wildlife Service, Greenland Institute of Natural Resources.
Right: Track lines showing the overall movement during 1991-2001 of polar bears instrumented with satellite transmitters in the
Davis Strait-Baffin region and adjacent areas. A certain degree of overlap between the different sub-populations is apparent.
Unpublished data: Nunavut Wildlife Management Division, University of Saskatchewan, Canadian Wildlife Service, Greenland
Institute of Natural Resources.
50°N