Ice Entrapment

Beluga stocks are often associated with ice, so it is not surprising that occasionally fast-forming ice entraps some whales, forming a "savsset". The term "savsset" describes the overcrowding that occurs when too many animals are dependent on too small an area of open water. Whales entrapped in a savsset have little chance of surviving due to the difficulty of maintaining breathing holes through the encroaching ice cover, scarcity of food within range of the breathing holes and stress.

Beluga savssets have been reported throughout the Arctic, including northern Bering Sea, southern Chukchi Sea, Gulf of Anadyr, Jones Sound, Lancaster Sound, Navy Board Inlet, Grise Fjord, Milne Inlet, southern Hudson Bay, along the west coast of Greenland, and Husky Lakes in the Beaufort area.

The Husky Lakes system consists of five interconnected, unnamed basins linked by two sets of narrow channels or fingers. It is approximately 200 km from the innermost basin to the outermost basin, which drains into Liverpool Bay. Water depths vary within the basins, the middle basins being shallower than the innermost and outermost basins, with an average depth of 13m. The Husky Lakes are ice-covered for approximately eight months of the year, from mid-October until mid-June.

There is a rich diverse fish community in the lakes; more than 18 fish species have been found. Beluga, mainly bachelor pods, enter the lakes to feed in late July and August. Belugas are regularly observed at the mouth of Liverpool Bay and in the outer three basins of the Husky Lakes. Some whales travel deep into the lake systems. As many as 2,000 whales have been estimated in the lakes area in some years. Most whales that enter the area, leave the lakes before freeze up. A few whales may not leave in time and become trapped. This has happened about once per decade, on recent record.

Records of ice entrapment in the Husky Lakes are available for 1966, 1969, 1974, 1989, 1996, 2006 and 2007. In these instances, beluga apparently did not locate the narrow channels leading from the Lakes back out to Liverpool Bay. The largest number of beluga that have been trapped in one season was 125 in 1989. Usually the number trapped is less than 30. The whales attempt to overwinter in the Lakes by maintaining breathing holes. Reports indicate that mortality usually occurs in the ice entrapments, but anecdotal information from long-time residents suggests sometimes the overwintering is successful. Certainly the number of whales trapped does not constitute a threat to the stock, which is estimated to be approximately 40,000 animals.

During some of the most recent entrapments, members from the Inuvik and Tuktoyaktuk Hunters and Trappers Committees, with support from the Department of Fisheries and Oceans and the Fisheries Joint Management Committee, removed whales from the breathing holes. In late November 1989, 87 whales were removed from three breathing holes; in December 1996, 20 beluga were removed from one breathing hole; and in November 2006, 37 beluga were removed from one breathing hole. Most of the removed whales were starving and in poor condition because of the entrapment. Some of the whales were not emaciated and were used for food.

Samples were taken from whales in each of the entrapment situations. The sampled whales were mostly males (from 70 to 90%), average ages were 11 to 19 years, and the average lengths were smaller than the median length of males and of females from the harvest.