Category Archives: Sea ice habitat

Pacific walrus sob stories begin again

Now we have poor hunting conditions in the Bering Strait touted as evidence that “walrus migration patterns have changed” with the implication that this is because “…the past eight years have had the eight lowest amounts of summer sea ice on record” due to man-made global warming.

Walrus 2012 July USGS

A subsistence lifestyle is hard, particularly so if it depends on a highly mobile, migratory herd animal. Think Barren-ground Inuit caribou hunters, who often starved because herd sizes declined for a few years or moved unpredictably.

Many factors – seasonal weather, last year’s winter conditions, size of the herd, food supply – all affect where and when a migratory herd will move and the likelihood it will be positioned for optimal harvesting by hunters. Add another highly variable factor into that – Bering Sea ice – and you have a highly unpredictable food supply, especially if you sit in one spot (like on St. Lawrence Island) and expect that migratory herd animal to come within reach.

Hunting walrus from St. Lawrence Island depends on just the right combination of ice and winds. Too much ice is not good, too much open water is not good, and too much wind is not good.

Alaska Dispatch, courtesy the Associated Press, reports St. Lawrence natives are again short of walrus meat because of “warm temperatures”: “Warming temps push walrus north, leaving Alaska villages without traditional food source” (Rachel D’Oro, The Associated Press, August 6, 2015). And the caption of the above USGS (A. Sonsthagen) photo predictably implies all current hunting troubles can be blamed on climate channge:

“The walruses in this July 2012 file photo are hauled out in the Eastern Chukchi Sea. Walrus migration patterns have changed as sea ice and other environmental factors have shifted — and that’s spelled trouble for Alaska Native communities who hunt them for subsistence.”

The people of St. Lawrence Island and the Bering Strait that depend on walrus for subsistence have my sympathy, they indeed have a hard life – but this is not a tale of woe about the status of Pacific walrus and changing summer sea ice.

Bering Strait natives hunt walrus in spring, from mid-April to early June (Huntington et al. 2013). All indications are that walrus are moving differently than they used to in summer because the population is now very large.  As far as I know, there is no new population information on walrus that wasn’t available last year, when I covered this topic extensively (Crockford 2014; video below).


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Long underwater stalk by polar bear shows how hard it is to catch seals in summer

The longest-ever-recorded underwater dive by a polar bear, stalking three bearded seals, shows in striking fashion how truly difficult it is for a polar bear to catch a seal from summer sea ice. After the long dive, the bear (see below screen capture) erupts from the water to try and take the seal resting on the ice but it escapes.

Underwater stalk_01

The paper reporting this dive, by Ian Stirling and photographer and Arctic expedition organizer Rinie van Meurs, has hit the news again in a big way, as it finally appeared in print. I wrote about it in June here, when it came out in press. The video was shot on 19 August 2014, at the height of the Arctic summer (July, August, September).

CBC Radio posted the video and interviewed  van Meurs yesterday (“As It Happens” 4 August), in which he reportedly made this astonishing statement:

“…after 27 years working, I have seen clearly changes in the sea ice. I don’t need to see the NASA records and graphs and all that.”

Indeed, who needs science and all that? You just have to look out the window of your ship! Anecdotal reports are what count as evidence to people who are not scientists. Van Meurs, who is not a scientist, is who the media gets to interview. Where’s co-author Stirling, the scientist?

More stills from the van Meurs video below – too bad, so sad, the bear gets no seal. Why polar bears eat little in the summer even if they are out on the ice hunting, as I discussed here.

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July 2015: all 13 collared polar bears in the Southern Beaufort are out on the sea ice

Most of these bears are close enough to shore to hit the beach if that’s where they wanted to be but they’re on the sea ice.

Polar bear S Beaufort_PolarBearNews2010

I’ve been posting these USGS tracking maps for two years.1  The map archive at USGS goes back to December 2009.  Seeing all animals on the ice in July is usual for Southern Beaufort polar bears.

During August, a few of these females usually come ashore (see here and here), probably because they plan to den there later. But most polar bear females stay out on the ice, no matter how far it contracts into the Arctic Basin. Only about 5% of SB bears spend time on land during the summer.

See the July track map below and some sea ice maps and graphs for the region.
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Hudson Bay, Davis Strait and Foxe Basin sea ice highest since 1992

We are seeing one of the extremes in Hudson Bay sea ice variability this year, not only in extent but in distribution of ice. Ice coverage on Hudson Bay this year at 28 July was twice what it was in 2009, the last “late” ice breakup year for which detailed ice maps are available (409 vs. 204 thousand km2), according to NSIDC MASIE ice maps. Canadian Ice Service data show 2015 coverage for the week of 30 July was the highest since 1992.

Churchill_Polar_Bear_2004-11-15 Wikipedia

The odd pattern of ice distribution presents a conundrum. Have a look at the maps and graphs below.

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Researcher says most S. Hudson Bay polar bears still on the ice, may have to swim home

More than half of Southern Hudson Bay polar bears under study are still out on the thick Hudson Bay sea ice that’s been giving Canadian Coast Guard icebreakers so much trouble.

Figure 6. James Bay polar bear female and her cub during the ice-free period. Notice how fat they both are. Courtesy Ministry of Natural Resources, News Ontario, June 2, 2009.

James Bay polar bear female and her cub on shore. Courtesy Ministry of Natural Resources, News Ontario, June 2, 2009.

As I pointed out a few days ago, most of the ice remaining on Hudson Bay is in the region used by Southern Hudson Bay polar bears. While you wouldn’t know it from the Polar Bears International “Bear Tracker” – which hasn’t been updated since 2 July – on Friday (24 July 2015) Ontario polar bear researcher Martyn Obbard used the PBI website to reveal where his study sample of polar bears are located.

Obbard posted a little essay on PBI’s “Save our sea ice!” website which had, buried near the end, the admission that on 20 July, five out of his nine Southern Hudson Bay females with satellite radio collars were still out on the ice, “far from the Ontario coast.
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Polar bear habitat update: Eastern Canada well above normal, lots of sea ice worldwide

Sea ice in at least three Eastern Canadian polar bear subpopulations is well above normal for this time of year, which means many bears are likely not ashore yet. The same is true in the Beaufort and Barents Seas – ice is melting but there is still a fair amount of sea ice close to popular shores. Cause for cheering, not raising alarms.

Stirling 01 no date_sm

Southern Hudson Bay, Foxe Basin, and Davis Strait, all have above average sea ice coverage, according to the Canadian Ice Service (see charts below).

Sea ice concentration in Canadian waters at 23 July 2015. Canadian Ice Service. Click to enlarge.

Sea ice concentration in Canadian waters at 23 July 2015. Canadian Ice Service. Click to enlarge.

Hudson Bay ice levels are particularly striking: the anomaly map below (“departure from normal”) is almost entirely blue (positive), showing how far it is above average. No wonder supply ships needed icebreaker help yesterday to get into Inukjuak on the eastern shore. Most of the ice is technically in the Southern Hudson Bay polar bear subpopulation region, which has a stable population.

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Heavy ice in Hudson Bay derails ArcticNet global warming research plans: irony bites

Heavy ice in Hudson Bay derails CCGS Amundsen’s research plans” – just in from the CBC (22 July 2015, via Twitchy). Worst ice in 20 years.

ccgs-pierre-radisson-in-sea-ice_to_Iqaluit_july 17_2015

[original caption for the above photo: “The CCGS Pierre Radisson escorts the oil tanker Havelstern to Iqaluit July 17. Tough ice conditions in area have delayed this summer’s annual resupply, and have now derailed the CCGS Amundsen from its carefully planned summer research program.”]

Worst ice conditions in 20 years force change of plans to icebreaker research program

That would be 1992 they’re talking about, the cold year that everyone blamed on the eruption of Mt. Pinatubo. Unfortunately, there are no good detailed ice maps from 1992 (see previous post here). What’s the excuse this year?

CCGS Amundsen is an icebreaker that is usually released from duty to serve as an Arctic research vessel in the summer. And who’s on board? GEOTRACES 2015 Arctic Expedition out of the University of British Columbia with a plan to study (in part) global warming caused “ocean acidification.” Their short blog post shows a map without ice and not a hint they see the irony of the situation.

Here’s the ice they’re talking about (from the Canadian Ice Service), with the communities mentioned in the study marked:

Sea ice at 22 July 2015, with Inukjuak (EHB) and Iqaliuk, Baffin Island marked. Click to enlarge.

Sea ice at 22 July 2015, with Inukjuak, Eastern Hudson Bay, and Iqaliuk, Baffin Island, marked. CIS map. Click to enlarge.

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Alarm over future summer polar bear habitat disguises how good conditions are right now

Despite the public outcry last week over future polar bear survival, the polar-bears-are-doomed crowd can’t hide the fact that this year, spring sea ice habitat for polar bears worldwide has been excellent.

A polar bear walks on the Arctic Ocean ice Aug. 21, 2009.

This year on 19 July, for example, Hudson Bay had greater than 150,000 square km more sea ice than there was in 2009 on that date (526.2 vs. 368.5 mkm2)(1992 was a particularly cold year and most bears left the ice as late in 2009 as they did in 1992).1 Conditions have also been excellent for pregnant females around Svalbard – Norwegian polar bear researchers recently reported a good crop of cubs this spring.

Hudson Bay breakup July 20 2015_CIS

Worldwide, there was exactly the same amount of Arctic sea ice present on 18 July 2015 as there was back in 2006 (Day 199) – 8.4 mkm2. By 19 July (day 200), 2015 had more ice than 2006 (8.4 mkm2 vs. 8.3).

All this means that recent summer ice melt has not impinged on the spring feeding period that is so critically important for polar bears. So much ice left in early summer means there was lots of sea ice in the spring (April-June), even in the Southern Beaufort Sea.

The only region with sea ice coverage well below the last five years is the Chukchi Sea (see plots below, click to enlarge). So why aren’t we hearing the-sky-is-falling stories about Chukchi bears? Because biologist have already demonstrated that polar bears in the Chukchi do very well even with no summer sea ice.
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New paper finds experts were wrong: polar bears are not “walking hibernators”

A polar bear paper just out in Science concludes the experts were wrong, polar bears are not “walking hibernators” – in summer, they slow down and live off their accumulated fat just like other mammals. Take home message: experts are not infallible and spring fat is critical for polar bear survival over the summer.

polarbears-arcticnatlwildliferefuge-suzannemiller-usfws_labeled_sm

This paper presents no compelling evidence that Southern Beaufort polar bears, or those in any other region, lack the ability to survive predicted summer sea ice declines in future decades – although they claim it does. See what you think.
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Polar bear habitat looking good for early summer – last days before the fast

Some polar bears may already be living mostly off the fat put on over the spring but others may catch a seal or two on the sea ice before the summer fast begins – since the ice hasn’t left the coast in most regions quite yet. Polar bears eat little in summer, whether they spend their time on land or on the sea ice.

PolarBearCV1LG_USGS

Sea ice is still high over Hudson Bay – for this time of year, it hasn’t had this much polar bear habitat since 2009. Davis Strait and Foxe Basin are also above average – Davis Strait hasn’t had this much ice since 1992 (the Mt. Pinatubo cold year). Polar bear subpopulation refresher map below.

PB map-all-populations PBSG original plus Okhotsk
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