Tag Archives: Hudson Bay

Breakup of sea ice on track in Canada as critical feeding period for polar bears ends

Relative to recent years and potential impacts on polar bear health and survival in Canada, there is nothing alarming in the pattern or speed of sea ice breakup for 2017, either over Hudson Bay, the southern Beaufort, or the eastern high Arctic.

Sea ice Canada 2017 June 8

Last year at this time (see map below), there was more open water in Hudson Bay and in the Southern Beaufort yet the polar bears came ashore in fine shape that summer and there was no hue-and-cry of dying bears anywhere. Breakup this year is on track to be about 3 weeks earlier than it was in the 1980s, as it has been since at least 2001, a conclusion reached by polar bear specialists (Castro de la Guardia et al. 2017; Lunn et al. 2016), who examined sea ice breakup to 2015.

Sea ice extent Canada 2016 June 8 CIS

Here are critical words to remember (more details here) from biologist Martin Obbard and colleagues (2016:29) on the relationship between body condition and sea ice for Southern Hudson Bay (SH) polar bears, which apply equally well to bears in other regions:

Date of freeze-up had a stronger influence on subsequent body condition than date of break-up in our study. Though models with date of freeze-up were supported over models with other ice covariates, we acknowledge that lower variability in freeze-up dates than in ice duration or break-up dates could have influenced the model selection process. Nevertheless, we suggest that a stronger effect of date of freeze-up may be because even though break-up has advanced by up to 3-4 weeks in portions of Hudson Bay it still occurs no earlier than late June or early July so does not yet interfere with opportunities to feed on neonate ringed seal pups that are born in March-April in eastern Hudson Bay (Chambellant 2010). Therefore, losing days or weeks of hunting opportunities during June and July deprives polar bears of the opportunity to feed on adult seals, but does not deprive them of the critical spring period (Watts and Hansen 1987) when they are truly hyperphagic. No doubt, the loss of hunting opportunities to kill adult seals has a negative effect on body condition, but it appears that for bears in SH a forced extension of the fast in late fall has a greater negative effect on subsequent body condition.” [my bold]

In other words, by mid-June at least (maybe earlier), polar bears have largely finished their intensive feeding that’s so critical to their survival over the rest of the year.

That’s why the latest count of SH polar bears (Obbard et al. 2015) showed a stable population (and see this recent post on WHB polar population estimates). But freeze-up was late last year and that’s what will make the difference to polar bears over the coming year.

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Much more sea ice in NW Hudson Bay this year than 2016 or 2015 at 27 May

In recent years, sea ice loss over Hudson Bay has begun with open water in the NW corner (which is just as likely due to prevailing offshore winds as ice melt) rather than along the east coast but this year that patch of ice is smaller than its been for the last two years. In addition, despite two patches of open water at either end of the Beaufort Sea, most of the coast of Alaska is still covered in thick ice — much more than existed last year, yet masses of polar bears did not die as far as I know (actually, WHB bears came ashore in excellent condition last year).

Sea ice Canada 2017 May 27

Compare to previous years:

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Polar bear mating season winds down with lots of sea ice habitat available

Habitat for polar bears is abundant worldwide as the prime feeding season passes its peak and mating season for sexually mature bears winds down.

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Battle among polar bear males for the right to mate, from this 2011 DailyMail story here.

There is much more ice than usual around Svalbard in the Barents Sea and off Newfoundland and southern Labrador, home to ‘Davis Strait’ bears. There have been no media reports of polar bears onshore anywhere (since the third week of April in Newfoundland and late January in Svalbard).

Sea ice map below for 12 May 2017:

Svalbard ice extent 2017 May 12_NIS

Compare the extent and concentration of ice around Svalbard above (at 12 May 2017) to conditions that prevailed on the same date in 2015 (below), considered a “good ice” year for local polar bears (and the year of the last population size count which registered an increase over the 2004 count):

Svalbard ice extent 2015 May 12_NIS

There hasn’t been this much ice in the area at this point in the season for many years, especially to the north of Svalbard, and levels since late April have been above even the long-term average (disregard the huge downward blip, which is clearly a sensor malfunction of some kind):

Svalbard ice extent 2017 May 12 graph_NIS

In fact, ice is pretty solid throughout the Barents Sea and East Greenland at this time:

Barents Sea ice extent 2017 May 12_NIS

Across the Atlantic, the situation is similar, with unseasonably heavy sea ice off eastern North America and the Southern Beaufort Sea.

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Report of Hudson Bay polar bear onshore in winter is rare indeed – here’s why

Late February is still the dead of winter in the Arctic, a time when most polar bears are at their leanest and out on the sea ice trying to find seals – and that means yesterday’s report of a “very fat” polar bear onshore outside Inukjuak is unusual at face value – but my followup inquiry revealed details that make it even more startling.

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CBC North facebook entry 27 Feb 2017

At my request, CBC North reporter Priscilla Hwang reached out to the hunter involved, who is the mayor of the community. She was told the incident took place on Saturday 25 February 2017 and the very fat bear in the story was actually a young, subadult female.

Subadults are more likely to be in poorer condition than adults at any time of year, due to their lack of hunting experience and competition with adult males. So to see a young bear that’s very fat before the feeding begins is quite astonishing: it suggests that feeding opportunities out on Hudson Bay have been very good over the winter and/or this bear was a savvy hunter despite her youth.

According to the mayor’s report, this community hasn’t had a bear onshore in nearly 30 years. Polar bears in Hudson Bay travel with the retreating ice to the western and southern shores, so with some exceptions, bears usually only have access to the east coast during winter through spring.

Last winter saw an extraordinary number of reports of bears on shore in winter, most of them causing trouble (see summary here). This Inukjuak sighting is the second I’ve come across this year – the other was in Svalbard (a female with cubs). Whether this new pattern is due to more bears or lack of hunting leading to bears having less fear of people – or a bit of both – it’s not yet possible to say.

So under the circumstances, the mayor of Inukjuak’s decision to kill this bear for the protection of the community seems quite reasonable (given the extensive resources required in Svalbard to drive their problem bears away rather than kill them).

Excerpts from the CBC story, and some maps and charts, are below.
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Hudson Bay could be ice-free in winter within 5-10 years, says seal researcher

Ringed seal biologist Steven Ferguson, in a statement to a reporter from the Winnipeg Free Press, made one of the boldest predictions I’ve ever heard:

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“Hudson Bay could experience its first free winter within 5-10 years.”

You heard it here, folks. It appears Ferguson thinks Hudson Bay was never ice-free in winter even during the Eemian Interglacial, when the Bering Sea was ice-free in winter – something that has not come close happening in recent years (Polyak et al. 2010:1769).

Sounds like a bit of ill-advised grandstanding to me.

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An El Niño year late start to freeze-up on Hudson Bay: bears gearing up to hunt

There is no serious ice on the west shore of Hudson Bay yet (as the map below shows) but the winds have just shifted – instead of coming from the south, they are now blowing in from the north.

Freeze-up and a resumption of seal hunting for Western and Southern Hudson Bay polar bears looks imminent. The bears get out on the ice as soon as they are physically able, when the ice is about 3-4 inches thick (about 10 cm).

sea-ice-extent-canada-2016-dec-5_cis

I’m going to let Kelsey Eliasson from PolarBearAlley, on shore at Churchill, convey the gist of the freeze-up situation on the Bay.

Recall that freeze-up was late in both 1998 and 1999 – during the height of that strong El Niño warmth as well as the year following. Continue reading

No correlation between freeze-up dates for WHB sea ice & Churchill temperatures

This is a follow-up to my last post and this time, I’ll address the implied correlation between freeze-up dates for Hudson Bay and Churchill temperatures in November that is being made by folks who should know better .

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Monday, 14 November 2016 a.m, over at Polar Bears International [my bold]:

“As a new week starts in Churchill, the weather is the warmest we’ve ever seen at this time of year. The tundra is muddy, with remnant patches of snow, and the bay is ice-free.” PBI Blog (no author designated)

Well, that may be true for the last few years – the high on 14 November 2016 (-1.20C) was the highest since 2012.

Andrew Derocher made a similar statement on the 4th (my bold):

There’s no sea ice anywhere in Hudson Bay yet—not even in the northern part of the Bay where ice should be forming. It’s above freezing today and if the forecast holds, it will be a record high for this date. It was 10 degrees colder last year at this time.”

Derocher is being unscientifically vague here and also misleadingly cites highs and lows as if they were the same. In fact, according to weather records kept by Environment Canada, for 4 November 2016 at Churchill, the daily high was +1.50C (compared to –1.50C in 2015). The daily low in 2015 was -15.30C, a 10 degree difference. The next-highest temp. for that date since 2012 was +0.70C in 2014 – hardly an earth-shattering difference.

However, if you are trying to draw conclusions about climate, you should go back at least 60 years (two climate periods of 30 years each). Temperature records for Churchill go back to 1943, which can be used to assess the claim for the 14th of November made by PBI.

According to weather records kept by Environment Canada, for 14 November at Churchill, the year with the highest temperature was 1975 (+2.20C):

churchill-weather-averages-and-extremes-2016-ec-14-nov

That was Monday. But as of yesterday, the weather recorded – and the forecast for the following week (17-23 November) was quite different, as the screencap below shows:

churchill-weather-2016-abnormal-cold-17-23-nov

The final recorded max. for yesterday (Thurs. 17 Nov) was -9.70C vs. a min. of -17.70C. So, a bit warmer during the day than predicted but as cold as expected overnight.

And for today, the current temperature in Churchill, as I write this is, is -190C (-310C with the wind chill) and the year with the highest temperature recorded for 18 November was 1944 (0.00C) – which was also the highest temperature for the 19th, recorded in 1943.

Ice maps and historical background below. See last post for recent multi-year comparison.
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