Tag Archives: Hudson Bay

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.

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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.

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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.

 

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

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Polar bear research on hold in Western Hudson Bay due to COVID-19 restrictions

After spring polar bear research was cancelled in Western Hudson Bay (and pretty much everywhere else) this year because of Covid 19 concerns, it now transpires that fall research is out as well. Travel restrictions implemented by government departments and university administrations (not the health department) apparently mean fall programs to assess the health and status of polar bears in Western Hudson Bay have been put on hold.

Triplet litter of polar bear cubs spotted in Wakusp National Park, Western Hudson Bay. 23 October 2020. Courtesy Explore.org.

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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).

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Amid crying over low Arctic ice, W Hudson Bay polar bears leave ice as late as 2009

This year, the last collared Western Hudson Bay polar bear to leave the ice left as late, or later, than the last collared bear did in 2009 (which was an unusually late breakup year) and so far, all bears spotted have been in good physical condition despite inhabiting one of the most southern regions of the Arctic. All the while, sea ice experts have been hand-wringing about low Arctic sea ice –– in general and as polar bear habitat.

Polar bear Cape East 0 Wakusp NP _24 Aug 2020 earlier

A female with two yearling cubs on the shore of Wakusp National Park, Western Hudson Bay on 24 August 2020. Taken via livecam from almost a mile away.

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Few bears on the ice off Western Hudson Bay at 14 August but will be onshore soon

Polar bear biologist Andrew Derocher published a tracking map of his collared polar bear females that shows one bear (out of 11) still on the rapidly diminishing ice north of Churchill in Western Hudson Bay – and where there is a collared female, there is almost certainly other bears doing the exact same thing:

Derocher 2020 WHB tracking map 14 Aug_1 bear still on the ice

Without evidence to support such a claim, Derocher (below) assumes this collared female is probably hunting seals. In fact, last year he admitted that most bears on Hudson Bay from at least July onward are unlikely to be successfully hunting seals:

Derocher 2020 Aug 14_1 bear still on the ice at 14 Aug odd behaviour

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Many W Hudson Bay polar bears still offshore at 7 August despite apparent low ice levels

Contrary to all expert expectations, five female polar bears (45%) out of eleven that had tracking collars attached last year were still out on the sea ice that’s lingering along the western shore of Hudson Bay as of 7 August. And if five collared bears are out there, then there are almost certainly many more without collars doing the same thing. This pattern of bears staying out on the ice long after the so-called ‘critical threshold’ of 50% concentration has passed has been going on since at least 2015 and many bears on tracking maps in July and August appear to be on ice that doesn’t exist.

Chukchi Sea polar bear Arctic_early August 2018_A Khan NSIDC small

There are two explanations for this pattern and both are likely true: 1) much more ice actually exists on Hudson Bay than satellites can detect and 2) polar bear experts are wrong that Western Hudson Bay polar bears head to land soon after sea ice concentration drops below 50%. Models that predict a catastrophic future for Western Hudson Bay polar bears (Castro de la Guardia et al. 2013; Molnar et al. 2020) assume that ice coverage of less than 50% in summer greatly reduces polar bear survival. However, if polar bears do not always head to land when sea ice drops below 50% then the models cannot possibly describe their future accurately. In other words, depending on the discredited ‘worst case’ RCP8.5 climate scenario for the most recent polar bear survival model that extrapolates from Western Hudson Bay bear data to many other subpopulations, as I discussed previously, may not be its only fault.

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Six good years in a row for the polar bear subpopulation used to predict species demise

In something resembling a new pattern for Western Hudson Bay polar bears, most of the animals are still out on the ice in late July this year, just like they were in the 1980s. The same thing happened last year but was brushed off as a happy anomaly. However, after last fall’s 1980s-like early freeze-up, this makes the sixth year in a row of good to very good sea ice conditions for Western Hudson Bay polar bears. No wonder polar bear experts haven’t published these data: good sea ice conditions along with polar bears coming ashore fat and healthy are not just inconvenient – they threaten to destroy the extinction panic narrative that depends on Western Hudson Bay bears showing evidence of harm from reduced sea ice.

WH 18 Sat July 2020 noon PT Cape East fat mother and cub_Wakusp NP explore dot org livecam

Fat mother and cub onshore at Wakusp National Park, Western Hudson Bay 18 July 2020, one of the first of the season.

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