Chukchi Sea (CS)

Status table outtake

Table comment: Abundance estimates are not available. The trend is believed to be declining and the status relative to historical levels is believed to be reduced based on legal/illegal harvest levels that were thought to be unsustainable. Sea ice loss is one of the highest levels in the Arctic. Combined impacts of high levels of legal/illegal harvest with rapid sea ice loss suggest that the risk for depletion is likely high.

Reliable estimates of subpopulation size or status based upon mark-recapture or other techniques (e.g., aerial survey) are not available for CS. This subpopulation is believed to be declining based on reported high levels of illegal killing in Russia combined with continued legal harvest in the United States, and observed and projected losses in sea ice habitat.

Cooperative studies between the US and Russia in the late 1980s and early 1990s revealed that polar bears in CS, also known as the Alaska-Chukotka subpopulation, are widely distributed on the pack ice of the northern Bering, Chukchi, and eastern portions of the East Siberian seas (Garner et al. 1990, 1994, 1995). Based upon these telemetry studies, the western boundary of the subpopulation was set near Chaunskaya Bay in northeastern Russia. The eastern boundary was set at Icy Cape, Alaska, which is also the western boundary of the southern Beaufort Sea subpopulation (Amstrup and DeMaster 1988, Garner et al. 1990, Amstrup et al. 1986, 2004a, 2005). Movement data have been used to determine probabilistic distributions and zones of overlap between CS and Southern Beaufort Sea subpopulations. This information can be used to more accurately describe sustainable harvest levels once defensible estimates of abundance are developed (Amstrup et al. 2004a, 2005). An on-going capture-based research program started in 2008 off the US coast of CS by the US Fish and Wildlife Service and the US Geological Survey will provide updated information on bear movement patterns and distribution.