Tag Archives: habitat

Low Bering Sea ice mostly due to south winds, no data on an impact for polar bears

Sea ice in the Bering Sea this winter was said to be the lowest since the 1850s, largely driven by persistent winds from the south rather than the usual north winds although warm Pacific water was a factor early in the season (AIRC 2018). But what, if any, impact is this surprisingly low winter and spring ice cover likely to have on Chukchi Sea polar bear health and survival?

Rode and Regehr 2010_Chukchi_report2010_Fig1_triplets_labelled

In fact, research on Chukchi Sea polar bears has included so few examples of individuals utilizing the Bering Sea in winter (Jan-March) and early spring (April-May) that any conclusions regarding an impact from this year’s sea ice conditions are likely to be invalid. In short, we don’t know what will happen since it has not happened before within living memory; the opinions of polar bear specialists must be taken with a grain of salt because so many of their previous assumptions have turned out to be wrong (Crockford 2017a,b, 2018), see here, here, and here. Seals, walrus and polar bears are much more flexible and resilent to changes in habitat conditions than most modern biologists give them credit for and consequently, it will be fascinating to see how the ice will change over the coming months and how the animals will respond.

Sea ice extent 2018 March average NSIDC

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Winter polar bear sea ice habitat by early March 2018 varied little from 2006 or 2017

Here’s a polar bear habitat update for early March: some folks are wringing their hands over the relatively extent of ice this season but ice maps show that as far as polar bear habitat is concerned, conditions are not materially different this year from what they were in 2006 or 2017. There is still plenty of late winter sea ice for polar bears needing a platform from which to hunt Arctic seals, which in some areas will have already begun giving birth to their fat furry pups (harp seals first, other species later).

The MASIE map for 5 March 2018 (Day 64) shows ice extent at 14.5 mkm2:

masie_all_zoom_4km 2018 March 5

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Experts talk of their bleak future, W Hudson Bay polar bears get earliest freezeup in decades

It seems that Churchill residents and visitors woke up this morning to find most local polar bears had left to go hunting — on the sea ice that supposedly doesn’t exist. Right in the middle of the Polar Bear Week campaign devised by Polar Bears International to drum up donation dollars and public sympathy for polar bear conservation!

Polar bear on the sea ice_Churchill_8 Nov 2017_Explore dot org cam my photo 2Frigid temperatures and north winds last night helped the process along, but this early freeze-up has been in the works for almost a week. From what I can ascertain, it appeared the only bears around onshore today were a mother with her young cub moving out towards the ice (females with cubs are usually the last to move offshore, probably to reduce the risk of encounters with adult males who might kill the cubs).

Tundra Buggy cams at Explore.org have been showing markedly fewer bears today and those that have been seen were on the ice (see above and below) or heading out to it.

The chart below is for yesterday (7 November), before the cold and north winds hit the region. It shows the concentration of ice that’s >15 cm thick.

Hudson Bay North 2017 concentration Nov 7

The chart for 8 November is below, after the storm.

Hudson Bay North daily ice concentration 2017_Nov 8

This is ice thick and extensive enough for polar bears to go hunting. Some bears almost certainly left shore yesterday, with the rest following quickly on their heals today. There are sure to be some stragglers left ashore that will leave over the next few days but the fact remains: there is sea ice to be had for those polar bear willing to start hunting.

Watch polar bear on the WHB sea ice below (screen caps below – and one above – were taken the afternoon of 8 November, from the Tundra Buggy Cam live feed near Churchill).

Polar bear on the sea ice_Churchill_8 Nov 2017_Explore dot org cam my photo 3

Keep in mind that in the 1980s, bears left for the ice on 8 November, on average. That means we’re back to a 1980s freeze-up scenario, at least for this year.

Funny how no one bothered to mention the potential for an early freeze-up to the media last week, when scientist were so eager to talk about the imminent demise of WHB bears. And funny that Polar Bears International hasn’t tweeted a word today about the famous Churchill bears having enough sea ice to go hunting, smack in the middle of Polar Bear Week.

Yes, the “Save Our Sea Ice” PBI rallying cry sounds a bit hollow with sea ice as far as the eye can see off Churchill today. But will anyone in the mainstream media point out the irony?

See charts below for years back to 2004, on this date (2005 missing for some reason), to compare to the above 8 November image (2004 is as far back as the archive goes).

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Svalbard polar bear habitat higher than average – here’s what that looks like

Polar bear habitat around Svalbard in the Barents Sea is currently slightly above average for 23 June 2017: this short post records what that amount of ice looks like according to the Norwegian Ice Service (NIS).

Svalbard ice extent 2017 June 23_NIS from archive

Compare to 2015 at the same date, the year that the last polar bear count was conducted for the Svalbard region, when many cubs were seen and the bears were reported in excellent condition:

Svalbard ice extent 2015 June 23_NIS from archive

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W Hudson Bay polar bears won’t have an early breakup year, according to sea ice charts

There is still a huge swath of highly concentrated thick first year ice (>1.2m) over most of Hudson Bay this week (19 June 2017) and even in the NW quadrant (the closest proxy we have for Western Hudson Bay), the weekly graph shows levels are greater than 2016, when WHB bears came off the ice in good condition about mid-July. All of which indicates 2017 won’t be an early sea ice breakup year for WHB polar bears.

Hudson Bay weekly ice stage of development 2017 June 19

There is thick first year ice (>1.2m, dark green) in patches along the west coast in the north and south. Thick first year ice also extends into Hudson Strait and Baffin Bay, with some medium first year ice (0.7-1.2m thick, bright green) along the central and southern coasts of WHB.  Note the red triangles incorporated into the thick ice of Hudson Strait in the chart above: those are icebergs from Greenland and/or Baffin Island glaciers. A similar phenomenon has been noted this year off northern Newfoundland, where very thick glacier ice became mixed with thick first year pack ice and were compacted against the shore by storm winds to create patches of sea ice 5-8 m thick.

Compare the above to what the ice looked like last year at this time (2016 20 June, below). There is more open water in the east this year (where few WHB bears would likely venture anyway) but less open water around Churchill and Wapusk National Park to the south than there was in 2016:

Hudson Bay ice age weekly at 20 June 2016

We won’t know for several more weeks if most WHB bears will come ashore at about the same time as last year (early to mid-July) or whether they will be in as good condition as they were last year (because winter conditions may not have been similar).

But so far, sea ice conditions are not looking as dire as the weekly “departure from normal” chart (below, 19 June 2017) might suggest (all that “less than normal” red and pink, oh no!!):

Hudson Bay weekly departure from normal 2017 June 19 Continue reading

Late winter polar bear habitat 2017 vs. 2006 and 2011 shows no trend

Here is a bit of historical perspective for rational readers trying to make sense of the doom-mongering of others that current sea ice conditions spell trouble for polar bears, given that the winter maximum extent for 2017 reached a new seasonal low (keeping in mind that NSIDC does not publish error bars for these measurements, which helps elevate such pronouncements to “news”).

Ice extent (courtesy NSIDC’s MASIE) at 25 March (Day 84) is below for 2017, 2011 and 2006, almost 3 weeks after the winter maximum was declared at 7 March for 2017, 9 March for  2011, and 12 March for 2006. Extent at the maximum for 2006 was estimated at 14.68 mkm2, 14.42 mkm2 for 2017, and 14.67 mkm2 in 2011 (what tiny differences make headlines these days).

Remember: there are no polar bears in the Sea of Okhotsk or in the Baltic Sea (marked with an * below) yet ice in those regions is included in the Arctic totals used to determine maximum seasonal extent. Much (and sometimes, all) of the “Arctic” variation in extent at this time of year is accounted for by variation in Sea of Okhotsk and Baltic Sea coverage.

Sea ice day 84 March 25 2017_2011_2006 labeled

Bottom line: total winter ice extent for the Arctic ≠ winter polar bear habitat and neither have changed much in a decade.

See close up of the above graphic below.

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Polar bear habitat update: Masie charts show more ice in 2017 than 2006

It’s just an observation but NSIDC Masie ice charts show 14.7 mkm2 of sea ice for 2017 at 19 February (Day 50) but only 14.3 mkm2 for 2006 (see them copied below).

In contrast, the NSIDC interactive graph shows almost the opposite: 14.3 mkm2 for 2017 and 14.4 mkm2 for 2006 (but with both below 2 standard deviations of average).

sea-ice-at-19-feb-2017_vs-2006_nsidc-interactive

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