Western Hudson Bay (WH)

Status table outtake

Table comment: 100% of PVA simulations resulted in subpopulation decline after 10 years. Subpopulation is declining without harvest. Local people are seeing more polar bears and TEK suggests that there may have been a northward shift in distribution.

The distribution, abundance, and population boundaries of the Western Hudson Bay (WH) subpopulation have been the subject of research programs since the late 1960s (Stirling et al. 1977, 1999, Derocher et al. 1993, 1997, Derocher and Stirling 1995, Taylor and Lee 1995, Lunn et al. 1997, Regehr et al. 2007). At times, over 80% of the adult population has been marked, and there are extensive records from mark-recapture studies and the return of tags from bears killed by Inuit hunters. This subpopulation appears to be geographically segregated from southern Hudson Bay to the southeast and Foxe Basin to the north during the open-water season, although it mixes with both subpopulations on the Hudson Bay sea ice during the winter and spring (Stirling et al. 1977, Derocher and Stirling 1990, Stirling and Derocher1993, Taylor and Lee 1995).

Between 1987 and 2004, WH declined from 1194 (95% CI = 1020, 1368) in 1987 to 935 (95% CI = 794, 1076) in 2004, a reduction of about 22% (Regehr et al. 2007). In particular, the survival of cubs, sub-adults, and old bears were negatively correlated with the date of breakup, i.e., the earlier the breakup, the poorer the survival and conversely. Before 1998 the subpopulation had apparently remained stable (Stirling et al. 1999), indicating that, prior to the onset of a decline brought about by the negative effects of climate warming, the annual harvest of approximately 50 bears had been sustainable.