Tag Archives: narwhal

Narwhal and beluga ice entrapment is natural – not caused by global warming

A part-time Arctic researcher eager for media attention suggested earlier today that the ice entrapment of narwhals in 2008 and again in 2015 at Pond Inlet (that made headlines around the world) was the result of “sudden changes in temperature” caused by climate change. This grossly misleading claim ignores the facts: ice entrapment of narwhals is an entirely natural feature of the Arctic that has been known about for hundreds of years.

Narwhals_at risk from climate change_CBC 13 Aug 2016 headline

Narwhals: the ‘giant unicorn of the sea’ at risk from climate change” (CBC, 13 August 2016), a print version of a CBC Radio interview with Clint Wright that aired 8 August 2016. Wright is the general manager at the Vancouver Aquarium and apparently has “joined a team of researchers to tag and study” narwhals for several years – but does not seem to know much about the history or circumstances of natural ice entrapment.

Ice entrapment of small whales is nothing new. The first formally documented incident – in English – occurred in 1915 (Porsild 1918) and the phenomenon has probably occurred as long as there has been ice in the Arctic (millions of years).

Animals routinely become trapped in a few specific areas due to local geography: when ice that forms in the north moves south quickly, it blocks the entrances to inlets or coastal bays that still have open water. The presence of the pack ice causes nearby  temperatures to drop quickly. Rapid development of ice on the bay proceeds from the mouth toward the head of the bay. Any whales present cannot escape to open water and will eventually die or be eaten.

Pond Inlet at the north end of Baffin Island is one such place but Disko Bay in western Greenland is another. In fact, Pond Inlet and Disko Bay are almost identical in geographic layout even though they lie on opposite sides of Baffin Bay, so it’s not surprising that both are locations of repeated entrapment events.

Three highly informative journal articles on the phenomenon of ice entrapment of narwhals and beluga are open access documents that reveal some fascinating details of such incidents, including polar bear predation on trapped whales. h/t T. Nelson Continue reading

Beluga whales frolic in the High Arctic

Belugas at arcticwatch_with addressIt’s Thanksgiving weekend here in Canada. As a special treat, I thought I’d point you in the direction of a delightful bit of video footage of beluga whales.

If you haven’t seen this Arctic Watch Beluga Foundation clip already, it’s worth a few minutes. It’s footage of belugas and their calves frolicking in the shallow water of Cunningham Inlet, on Somerset Island, Nunavut (within the Lancaster Sound polar bear subpopulation, which is north of the Gulf of Boothia subpopulation region that I discussed previously here and here).

While I previously surmised that Gulf of Boothia polar bears might hunt beluga from remnant ice during the summer in years when the ice doesn’t totally melt (like they do in Hudson Bay, see belugas as food for hungry polar bears), it appears they also successfully hunt beluga in shallow waters like those found in Cunningham Inlet. But there is no hunting footage in this post.

Link and further info below, including a map and references on beluga, and polar bear predation on beluga in this region.

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Sea ice, beluga whales, and polar bear densities in the Gulf of Boothia

As I discussed in my last post, the Gulf of Boothia subpopulation in the central Canadian Arctic has the highest density of polar bears anywhere in the world. The question is, why?

For example, is the sea ice in the Gulf of Boothia region so markedly different from its nearest subpopulation-neighbor, M’Clintock Channel (Fig. 1), that it accounts for the wide disparity in polar bear densities between the two? The differences, remember, are dramatic: Gulf of Boothia, 18.3 bears per 1000 km2 vs. M’Clintock Channel, 1.9. And while M’Clintock Channel may be low in part due to recent over-harvests (see footnote 1), even the density before over-harvests occurred in M’Clintock Channel were only 4.7, compared to 10.4 bears per 1000 km2 in Gulf of Boothia (see Table 1 in previous post).

Today, I’ll take a look at sea ice and ringed seal habitat in the Gulf of Boothia and M’Clintock Channel, as well as information from a study on polar bear diets, which together shine some light on why the Gulf of Boothia is such a great place for polar bears.

Figure 1. Map showing the side-by-side relationship of M’Clintock Channel and the Gulf of Boothia. From Barber and Iacozza (2004: Fig. 1).

Figure 1. Map showing the side-by-side relationship of M’Clintock Channel and the Gulf of Boothia. From Barber and Iacozza (2004: Fig. 1).

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