Davis Strait (DS)

Population size of 2,150 estimated using mark-recapture in 2007. Subpopulation likely increased over the last 30 years, and was assessed as stable in 2013.

Status table outtake

Size Sea ice metrics Human-caused removals 2010–2014
Estimate /
95% CI
Year Method Change in spring ice retreat / Change in fall ice advance (days per decade) Change in summer sea ice area (percent change per decade) 5-yr mean Last year
Potential Actual Potential Actual
2158
1833-2542
2007Physical capture-recapture-7.7/9.7-19.910210910896
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.

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 et al. 1980, Stirling and Kiliaan 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) 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 Southern Canada and northern DS to the Canadian Archipelago).

The initial subpopulation estimate of 900 bears for DS (Stirling et al. 1980, Stirling and Kiliaan 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, 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 (Pagophilus groenlandicus) 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 (Peacock et al. 2013, Rode et al. 2012).

References

Crompton, A.E., Obbard, M.E., Petersen, S.D., and Wilson, P.J. 2008. Population genetic structure in polar bears (Ursus maritimus) from Hudson Bay, Canada: Implications of future climate change. Biological Conservation 141: 2528-2539.

Paetkau, D., Amstrup, S.C., Born, E.W., Calvert, W., Derocher, A.E., Garner, G.W., Messier, F., Stirling, I., Taylor, M.K., Wiig, Ø., and Strobeck, C. 1999. Genetic structure of the world's polar bear populations. Molecular Ecology 8: 1571-1584.

Peacock, E., Taylor, M.K., Laake, J., and Stirling, I. 2013. Population ecology of polar bears in Davis Strait, Canada and Greenland. Journal of Wildlife Management 77: 463-476.

Peacock, E., Sonsthagen, S.A., Obbard, M.E., Boltunov, A., Regehr, E.V., Ovsyanikov, N., Aars, J., Atkinson, S.N., Sage, G.K., Hope, A.G., Zeyl, E., Bachmann, L., Ehrich, D., Scribner, K.T., Amstrup, S.C., Belikov, S., Born, E., Derocher, A.E., Stirling, I., Taylor, M.K., Wiig, Ø., Paetkau, D., and Talbot, S.L. 2015. Implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming Arctic. Plos One 10: e112021.

Rode, K.D., Peacock, E., Taylor, M., Stirling, I., Born, E.W., Laidre, K.L. and Wiig, Ø. 2012. A tale of two polar bear populations: ice habitat, harvest, and body condition. Population Ecology 54: 3-18.

Stirling, I., Calvert, W., and Andriashek, D. 1980. Population ecology studies of the polar bear in the area of southeastern Baffin Island. Canadian Wildlife Service Occasional Paper No. 44, 33 pp.

Stirling, I. and Kiliaan, H.P.L. 1980. Population ecology studies of the polar bear in northern Labrador. Canadian Wildlife Service Occasional Paper No. 42, 21 pp.

Taylor, M. and Lee, J. 1995. Distribution and abundance of Canadian polar bear populations: A management perspective. Arctic 48: 147-154.

Taylor, M.K., Akeeagok, S., Andriashek, D., Barbour, W., Born, E.W., Calvert, W., Dean Cluff, H., Ferguson, S., Laake, J. Rosing-Asvid, A., Stirling, I., and Messier, F. 2001. Delineating Canadian and Greenland polar bear (Ursus maritimus) populations by cluster analysis of movements. Can. J. Zool. 79: 690-709.