Lancaster Sound (LS)

A population size of 2,500 bears was estimated in 1998 using mark-recapture methods. Population is data deficient, but thought to be declining, because of highly selective harvest of male polar bears.

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
2541
1759-3323
1995-1997Physical capture-recapture-5.6/5.1-7.792.886.68980
See also the complete table (all subpopulations)

Comments, vulnerabilities and concerns

Demographic data are >15 years old. Selective hunting for males in the harvest decreased due to the US import ban and listing under the US ESA. Increase in shipping activities.

Status and delineation

Lancaster Sound subpopulation mapThe Lancaster Sound area. See also the complete map (all subpopulations).

Information on the movements of adult female polar bears monitored by satellite radio-collars, and mark-recapture data from past years, has shown that the Lancaster Sound subpopulation is distinct from the adjoining Viscount Melville Sound (VS), M’Clintock Channel (MC), Gulf of Boothia (GB), Baffin Bay (BB) and Norwegian Bay (NW) subpopulations (Taylor et al. 2001). Survival rates of the pooled NW and LS populations were used in the PVA to minimize sampling errors; the subpopulation estimate of 2,541 ± 391 is based on an analysis of both historical and current mark-recapture data to 1997 (Taylor et al. 2008). This estimate is considerably larger than a previous estimate of 1,675 that included NW (Stirling et al. 1984). Taylor et al. (2008) estimated survival and recruitment parameters that suggest this subpopulation has a lower renewal rate than previously estimated. However, what effect this may or may not have on the present population is not known, especially under changing sea-ice conditions. Currently, the population data are dated, but the population is thought to be stable based on local traditional information.

References

Boukal, D. S. & Berec, L. 2002 Single-species models of the Allee effect: extinction boundaries, sex ratios and mate encounters. J. Theor. Biol. 218, 375–394. (doi:10.1006/jtbi.2002.3084).

Canadian Wildlife Service. 2009. Nunavut consultation report – Consultations on the proposed listing of the Polar Bear as Special Concern under the Species at Risk Act. Report submitted to the Nunavut Wildlife Management Board in accordance with Step 3.8 of the Memorandum of Understanding to Harmonize the Designation of Endangered Species under the Nunavut Land Claims Agreement and the Species at Risk Act, 249 pp. [available at: http://assembly.nu.ca/library/Edocs/2009/001149-e.pdf].

Derocher, A. E., Lunn, N. J. and Stirling, I. 2004. Polar bears in a warming climate. Integr Comp Biol 44:163-176.

Kingsley, M. C. S., Stirling, I. and Calvert, W. 1985. The distribution and abundance of seals in the Canadian High Arctic, 1980-82. Can. J. Fish. Aquat.Sci. 42:1189-1210.

Markus, T., Stroeve, J. C. and Miller J. 2009. Recent changes in Arctic sea ice melt onset, freezeup, and melt season length. J. Geophys. Res. 114:C12024, doi:10.1029/2009JC005436.

Maslanik, J., Stroeve, J., Fowler, C. and Emery W. 2011. Distribution and trends in Arctic sea ice through spring 2011. Geophys. Res. Letters 38:L13502, doi:10.1029/2011GL047735.

McLoughlin, P. D., Taylor, M. K. and Messier, F. 2005. Conservation risks of male-selective harvest for mammals with low reproductive potential. J. Wildl. Manage. 69:1592-1600.

Molnár, P.K., Derocher, A.E., Lewis, M.A. and Taylor, M.K. 2008. Modelling the mating system of polar bears: a mechanistic approach to the Allee effect. Proc. Roy. Soc. B 275:217-226.

Schweinsburg, R.E., Lee, L.J. and Latour, P.B. 1982. Distribution, movement and abundance of polar bears in Lancaster Sound, Northwest Territories. Arctic 35:159-169.

Sou, T. and Flato G. 2009. Sea ice in the Canadian Arctic Archipelago: modeling the past (1950-2004) and the future (2041-60). J. Climate 22:2181-2198.

Stirling, I. and Derocher, A. E. 2012. Effects of climate warming on polar bears: a review of the evidence. Global Change Biology, 18:2694–2706.

Stirling, I., Calvert, W. and Andriashek, D. 1984. Polar bear ecology and environmental considerations in the Canadian High Arctic. Pp. 201-222 In Olson, R., Geddes F. and Hastings, R. (eds.). Northern Ecology and Resource Management. University of Alberta Press, Edmonton, Canada.

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

Taylor, M.K., Laake, J., McLoughlin, P.D., Cluff, H.D. and Messier, F. 2008. Mark-recapture and stochastic population models for polar bears of the high Arctic. Arctic 61:143-152.

Welch, H.E., Bergmann, M.A., Siferd, T.D., Martin, K.A., Curtis, M.F., Crawford, R.E., Conover, R.J. and Hop, H. 1992. Energy-flow through the marine ecosystem of the Lancaster Sound region, Arctic Canada. Arctic 45:343-357.