Killer whales trapped in Hudson Bay’s sea-ice
By Pete Ewins, WWF-Canada Arctic species specialist (and WWF lead on Arctic whales)
Read a view of the situation from our Senior Director of Conservation Science and Practice, Steven Price.
The nearest extensive open water is in Hudson Strait, over 600 km to the north, and not accessible by these whales since they need to breathe every 3-4 minutes . Hudson Bay sea-ice starts melting only in May – a full four months from now. Killer whales have not evolved in sea-ice, and have a large dorsal fin that prevents them from breaking ice from below.
The small area of open water was steadily freezing over, and the whales were in evident distress, as they surfaced to breathe. Cellphone and social media channels quickly brought this situation to international audiences. On January 9th or 10th the wind had changed, opening up other small areas of open water. The whales moved away and have as of this writing not been located. However, it is likely that the whales are still trapped in the Hudson Bay winter ice and unable to join other killer whales that in late fall would have moved out to winter in open waters of the North Atlantic. (The one killer whale fitted with a working satellite radio transmitter in the Canadian arctic had moved over 5,000 km to winter south of the Azores in the East Atlantic).
As global warming causes sea-ice cover to retreat northwards, the open-water season is increasing significantly, especially at the southern edges of the Arctic. This is allowing increased numbers and activity of killer whales (typically the top marine predator in ice-free situations), including in Hudson Bay. At the same time, polar bears (the top predator in ice-covered arctic oceans) are experiencing stress due to increased ice-free periods, especially towards the edges of their range. Experts have projected for a long time that these unprecedented rapid climatic changes will be accompanied by less predictability in sea-ice conditions. This is what is now playing out, and both wildlife species and Inuit hunters and other travelers on sea-ice appear to now have increasing difficulties in predicting and dealing with changing sea-ice dynamics.
Other whales have been trapped in sea-ice elsewhere in the Arctic, notably Belugas, narwhal, bowhead, and gray whales (all these species are prey of killer whales at times). Generally, nature takes its course, and if the open area freezes up entirely it results in the whales drowning. In some cases rescues have been attempted, but these are very costly and dangerous. In a few cases it has been necessary to kill the whales to end their suffering. At least for now, none of these options need to be decided upon, although the whales are almost certainly not yet out of danger. In Canada, the Government of Canada, through the Department of Fisheries and Oceans, is responsible for marine mammals, and the final course of action in such situations would be set in partnership with local and regional Inuit organizations.
WWF’s work in the Arctic is focused on ensuring that resilient habitats continue to exist for all marine mammals. This requires action now, both to plan for conservation needs in a rapidly changing environment, combined with concerted global actions to reduce our greenhouse gas emissions.
(c) Montreal Gazette
