Category Archives: Life History

Arctic report card 2020 highlights the huge benefit of less summer sea ice: more food

As well as summarizing sea ice changes, NOAA’s 2020 Arctic Report Card features two reports that document the biggest advantage of much less summer sea ice than there was before 2003: increased primary productivity. Being at the top of the Arctic food chain, polar bears have been beneficiaries of this phenomenon because the Arctic marine mammals they depend on for food – seals, walrus and bowhead whales – have been thriving despite less ice in summer.

Continue reading

Polar bears again attracted to Russian town by dead walrus Attenborough blames on no sea ice

In the news again: Cape Schmidt (on the Chukchi Sea) made famous by Sir David Attenborough’s false claim that walrus fell to their deaths because of lack of sea ice due to climate change when a clever polar bear hunting strategy was actually to blame.

Ryrkaypiy overrun by polar bears WWF photo

Ryrkaypiy overrun by polar bears Dec 2019 WWF photo

Last year in December (above), some bears were feeding at Ryrkaypiy’s garbage dump and wandering around town after being displaced from feeding on walrus carcasses by bigger, stronger bears on the nearby point.

This year, the town has managed to keep the bears out of town, so while the residents are having no real problems, more than 30 bears have been spotted near town, almost certainly feeding on natural-death carcasses of walrus along the shore (see photo below from 2017 where Ryrkaypiy can be seen in the background).

Continue reading

The conundrum of Hudson Bay bears that left shore late in 1983 with video from CBC archives

In 1983, it was claimed that freeze-up of Hudson Bay was so late that polar bears didn’t leave the shore until the 4th of December – several weeks later than had been usual at that time. However, the fact that sea ice charts show significant ice offshore weeks before that time suggests something else was probably going on.

About three weeks ago, CBC News republished an article (with video) from their 1983 archives for 1 December, about the plight of the people of Churchill who had already suffered one death and one serious mauling by polar bears. That was thirty-seven years ago, long before lack of sea ice was blamed for everything bad that happened to Western Hudson Bay polar bears. In fact, rather than a really late freeze-up, it appears the problem had more to do with the fact the bears had had an especially tough spring that year and arrived onshore in only ‘OK’ condition – and as a consequence, the town dump became such a strong attractant for many bears that they were reluctant to leave when the sea ice formed offshore.

Continue reading

Speculation on ice-trapped whales: science-based fiction vs. dishonest science

Ice entrapment of whales is known to happen across the Arctic, including Davis Strait and the Gulf of St. Lawrence. How common such phenomena were in the past or might be in the future are subjects of conjecture. However, while speculation is the bread-and-butter of science-based fiction, it is the bane of peer-reviewed science.

I’ve written two novels informed by science set a bit in the future (2025-2026) in Eastern Canada: EATEN was set in Newfoundland and my latest book UPHEAVAL –see a review here – is set in Cape Breton Island, Nova Scotia. In UPHEAVAL, one of the issues I explore is ice entrapment of large whales, like North Atlantic right whales. I speculate in the story whether carcasses of ice-killed whales might provide a powerful enough attraction to lure Davis Strait polar bears down from Labrador and the Strait of Belle Isle into the Gulf of St. Lawrence – and if they did, what might be the repercussions of that shift in distribution.

Here I argue that a novel is the appropriate place for this kind of speculation and researchers who offer such conjecture to the public in a way that conflates a science-informed guess with evidence-based fact risks eroding public trust in science.

Continue reading

Polar bear habitat update for late November

Sea ice formation is ahead of usual in some regions and behind in others but overall, sea ice habitat is abundant enough for this time of year for virtually all polar bears across the Arctic to be back out on the sea ice hunting seals.

Overall, there was more sea ice at 24 November 2020 than there was on the same date in 2016, which was the last year that a number of polar bear subpopulations were surveyed, including Western and Southern Hudson Bay, Southern Beaufort, Chukchi Sea (Crockford 2019, 2020), see graph below from NSIDC Masie:

Northern Hemisphere sea ice at 24 November, 2016-2020.

UPDATE 27 November 2020: Problem bear report published today (for week 13, Nov. 16-22) has been added below.

Continue reading

Strange sea ice pattern over Hudson Bay as winds blow polar bears offshore

Winds blew a huge mass of new shorefast sea ice way out into Western Hudson Bay a few days ago (13 November) and very likely took some polar bears with it. This offshore wind phenomenon is common at this time of year – it happened in 2017 – and is often part of the yearly ‘freeze-up’ process for sea ice. But the extent of ice and the distance blown offshore in Hudson Bay this year is impressive.

In previous years, this has happened very early in the freeze-up sequence, well before the ice was thick enough to support polar bears. This year is different: freeze-up was early (starting in late October) and the ice was thick enough off Western Hudson Bay to support bears hunting successfully for seals by the last day of October. By 7 November, most bears had left for the ice, with only a few stragglers left behind – since they were all in good condition due to a late breakup of the ice this summer, there were remarkably few problem with bears in Churchill and some seemed in no hurry to leave once the shorefast ice started to form.

It’s doubtful that any bears out on that wind-blown ice are in any kind of peril. As long as the ice is thick enough to support their weight, they should be fine – and keeping themselves busy catching seals.

The chart above is from NSIDC Masie for 15 November 2020 (Day 320) – it showed the same large offshore patch of ice the day before. However, only today did the Canadian Ice Service (CIS) chart show even part of the offshore patch (below):

In this case, I’m trusting the Masie chart because it seems the CIS sensors aren’t yet set to pick up ice that’s far offshore, as the detailed stage of development chart for 16 November (below) shows (grey-white ice is 15-30 cm thick, grey ice is 10-15 cm, but see discussion below):

However, after I’d almost given up that we’d hear from Andrew Derocher about his polar bears with still-functioning collars, he posted a tracking map late today (below). Even his chart shows that big patch of offshore ice but he didn’t comment on it at all. It appears that of the 9 collars he deployed on females last year only one is on the ice, well offshore (north of Churchill).

Derocher is still claiming that this is not an early freeze-up year even though it’s clear many bears have already left for the ice and only a few stragglers remain, including most of his collared bears. However, some of his bears are probably pregnant (especially the two furthest inland) and won’t be going anywhere this fall. And we already know that many of Derocher’s collared bears were very late to come onshore in August and having only spent 3 months onshore rather than 4 or 5 months they are used to, may now be in no hurry to leave – especially since they know that seals are to be had out on that ‘very thin’ ice just offshore.

Unfortunately, the Polar Bear Alert Program in Churchill decided not to issue a report for the first week in November (2-8 Nov), so there is no information on the progress of freeze-up and polar bear movements from that authority. There might be one issued tomorrow for the second week (9-15 Nov), if so I’ll post it here.

It’s important to know that even big male bears only need ice that’s about 30 cm thick to hold their weight. And while the newly formed grey ice is technically only 10-15 cm (see the stage of development chart above), the ice offshore this year is very compressed and buckled (see below from 7 November), making it thicker than it might appear on the official ice charts.

 

Shorefast ice formation and the fall feeding season for polar bears

What may seem like a silly question is actually fundamental to polar bear survival: in the fall, why do Western Hudson Bay bears correctly expect to find seals in the new ice that forms offshore? Why are seals attracted to that new ice – called ‘shorefast ice’ or ‘fast ice’ – when they would clearly be safer out in the open water where there is no ice and no bears?

As the picture below attests, polar bears can and do kill ringed seals in the new ice that forms off the coast of Western Hudson Bay even when it is but a narrow strip of thin ice – and so close to shore their successes can be caught on camera.

Three adult male polar bears share a seal kill on the newly-formed ice off Wapusk National Park, Western Hudson Bay. 5 November 2020. Buggy cam, Explore.org

A different bear was also filmed killing another seal on 31 October. And these are only the kills we know about along a very short stretch of coast – the killing is almost certainly going on up and down the entire coast, into James Bay (see below), where there is just as much ice but no cameras.

As far as I am aware, this seal killing by polar bears goes on in newly-formed shorefast ice everywhere across the Arctic in early fall, not just in Hudson Bay. Although the timing varies, virtually everywhere in the peripheral seas of the Arctic Ocean (Barents, Kara, Laptev, Chukchi, Beaufort, as well as Baffin Bay and Davis Strait), shorefast ice forms before the mobile ice pack expands to meet the ice developing from shore.

This shorefast ice formation in fall provides a predictable but short-lived source of prey for polar bears as they strive to regain some of the weight lost over the summer.

Continue reading

Western & Southern Hudson Bay polar bears experience earliest freeze-up in decades

This is shaping up to be one of the shortest ice-free seasons in at least 20 years for both Western and Southern Hudson Bay polar bears.

Hudson Bay sea ice at 2 November 2020. NSIDC Masie chart.

Last week, sea ice started forming along the shore of Hudson Bay, from the north end all the way south into James Bay. So far, the shorefast ice that’s forming is only a narrow strip along the coast but is thickening and becoming broader each day, which means that unless something changes dramatically, the bears should all be on the ice at the end of the week, an exodus from shore that hasn’t happened this early in WH since 1993 (the earliest since 1979).

The last WH tagged polar bear didn’t leave the ice this year until 21 August, which means if it’s on the ice by the end of this week it will have spent only 11 weeks onshore – less than 3 months. Even the first bears that came ashore in mid-July will have only spent about 16 weeks on land – at least a month less than they did a decade ago (Stirling and Derocher 2012). Four months spent ashore was the historical average for Western Hudson Bay bears in the 1970s and 1980s (Stirling et al. 1977, 1999). This year, most polar bears will have spent only about 13-14 weeks on land because they did not come ashore until early August.

UPDATE 8 November 2020: Report from Churchill area polar bear guide Kelsey Eliasson, via Facebook Saturday 7 November: “Most bears have left on the ice – including peanut – but still some stragglers” [Peanut’ is a well-known female who has two cubs this year]. See below for sea ice chart for 8 November shows broadening band of grey ice clearly thick enough to support the weight of adult bears (and the same thing is happening in Southern Hudson Bay):

Hudson Bay North daily stage of development 2020 Nov 8_all grey ice

Continue reading

My new novel set in the Gulf of St. Lawrence has a surprising twist

My fictional story about sea ice, polar bears and upheaval in 2026 – a followup to EATEN – is coming soon. Prepare for the unexpected.

CTV news_Cathy Erlene sealer heavy ice off North Sydney_Saturday March 28 2009

A video to help set the mood…

Some surprises in polar bear sea ice habitat at mid-October 2020

Arctic sea ice has been growing steadily since the minimum extent was reached a month ago, with shorefast ice now developing along the Russian and Alaskan coastlines as ice cover expands in the Central Canadian Arctic. So while it’s true that the main pack of Arctic ice is far from the Russian shoreline, rapidly developing shorefast ice will allow bears to begin hunting seals long before ice in the central Arctic Basin reaches the Siberian shore, as they do in Western and Southern Hudson Bay every fall.

Cropped sea ice extent at 15 October 2020 (Day 289), NSIDC Masie.

And speaking of Western Hudson Bay, it’s a very slow season around Churchill for problem polar bears (photo below) – the quietest mid-October for the Polar Bear Alert Program in the last five years and perhaps the quietest in decades (which I could say for sure if I had the records but I do not).

Continue reading