Davis Strait (DS)

Population size of 2,150 estimated using mark-recapture in 2007. Subpopulation likely increased over the last 30 years, but assessed as likely stable in the period 2007-2016.

Status table outtake

Subpopulation size Subpopulation trend Sea ice metrics 1979-2018 Human-caused removals 2013/2014–2017/2018
Estimate and uncertainity Method and type of evidence Year and citation Long term (approx 3 generations) Short term (approx 1 generation) Change in date of spring ice retreat / fall ice advance (days per decade) Change in summer sea ice area (percent change per decade) 5-year mean
Quota (bears per year) Actual (% of total population)
2158
1833-2542
Physical C-R2007Data deficientLikely stable (2007 to 2016)-5.6/6.7-19.2QC + 75.8 (NU & GL)84.4 (3.9%)
See also the complete table (all subpopulations)

Comments, vulnerabilities and concerns

Low recruitment rates may reflect negative effects of greater densities or worsening ice conditions; ongoing population assessment.

Status and delineation

Davis Strait subpopulation mapThe Davis Strait area. See also the complete map (all subpopulations).

Based on the recapture or harvest of previously tagged animals and tracking adult female polar bears with satellite collars, the Davis Strait subpopulation occurs in Canada within the Labrador Sea, eastern Hudson Strait, Davis Strait south of Cape Dyer, and along a portion of southwest Greenland (Stirling and Kiliaan 1980; Stirling et al. 1980; Taylor and Lee 1995; Taylor et al. 2001). A genetic study of polar bears (Paetkau et al. 1999) indicated significant differences between bears from southern DS and both Baffin Bay and Foxe Basin. Crompton et al. (2008, 2014) found that individuals from northern portions of DS and those from Foxe Basin share a high degree of ancestry. Peacock et al. (2015) used samples from both northern and southern DS in an updated circumpolar genetic analysis, and found that the two regions are so distinct as to belong to two different global genetic clusters (southern DS to Southern Canada and northern DS to the Canadian Archipelago).

The initial subpopulation estimate of 900 bears for DS (Stirling and Kiliaan 1980; Stirling et al. 1980) was based on a subjective correction from the original mark-recapture estimate of 726 bears, which was thought to be too low because of possible bias in the sampling. In 1993, the estimate was again subjectively increased to 1,400 bears and to 1,650 in 2005. These increases were to account for bias as a result of springtime sampling, the fact that the existing harvest appeared to be sustainable and not having negative effects on the age structure, and TEK that suggested that more bears were being seen over the last 20 years. In addition, harp seals (Pagophilus groenlandicus), an important prey species for that population, had increased dramatically over the same period, providing a much-enhanced potential prey base. Polar bears were seen and radio-tracked in the large pupping areas off the coast of southern Labrador in spring. The most recent inventory of DS was completed in 2007 and the subpopulation estimate was 2,158 (95% CI: 1,833–2,542) (Peacock et al. 2013) and the subpopulation has been assessed as stable. Polar bear survival in DS varied with time and geography, and was related to factors that included reductions in sea ice habitat and increases of harp seal numbers (Peacock et al. 2013). It was suggested that the observed lowered reproductive rates and declines in body condition of polar bears in DS were likely a result of habitat changes and/or polar bear density (Rode et al. 2012; Peacock et al. 2013).

During the fall of 2017 and 2018, the field component of a genetic biopsy capture-mark-recapture study was completed.

References

Reference list