Tag Archives: mating

Most Chukchi Sea ice in 20 years means no walrus feasts for polar bears at famous Russian cliffs

Posted on October 20, 2021 | Comments Off on Most Chukchi Sea ice in 20 years means no walrus feasts for polar bears at famous Russian cliffs

After years of hype, including documentary over-reach by David Attenborough and his collaborators at WWF and Netflix, there has been relatively abundant ice in the Chukchi Sea this summer, particulary along the Russian coast and around Wrangel Island, which in recent years have been important summer refuge areas for polar bears and Pacific walrus.

Walrus carcasses at the base of the cliff at Cape Schmidt, September 2017. Credit: Y. Basov.

This year, there has been nothing like the complete retreat of ice into the Arctic Basin as happened in 2007, 2012, and 2020. The chart below shows the ice extent at 11 October 2021:

Wrangel Island was surrounded by ice in 2000 and 2001, which made access to walrus haulouts on the island impossible (Kochnev 2004). Most of the walrus haulouts along the Chukotka coast were also ice-covered in September in those years, as were all of the western locations in 2021 – as the ice charts below show. The extra ice will have drastically affected the distribution of walrus this year, which in turn will have meant no walrus carcasses for polar bears to feast on as they have done for many years now.

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Earth Day 2021: celebrate abundant sea ice habitat for polar bear feeding and mating

Posted on April 22, 2021 | Comments Off on Earth Day 2021: celebrate abundant sea ice habitat for polar bear feeding and mating

Late April is the height of the most important polar bear feeding and mating season and there is abundant sea ice habitat across the Arctic for doing both.

Sea ice charts below. Compare to 2018 conditions here; 2015 here; and 2014 here. Sea ice maximum this year was apparently “uneventful” according to the folks at the NSDIC because it didn’t even come close to setting a new low record.

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Polar bear habitat update for early spring shows no influence of a CO2 control knob

Posted on May 13, 2019 | Comments Off on Polar bear habitat update for early spring shows no influence of a CO2 control knob

The primary feeding period for polar bears is rapidly drawing to a close in much of the Arctic, although it may continue for another few weeks in the farthest north. Mating is pretty much over as well, which means the polar bears’ need for abundant sea ice is declining even more rapidly than the ice does itself at this time of year.

Walking bear shutterstock_329214941_web size

Despite the fact that CO2 levels have now reached 415 ppm (see tweet below), sea ice is still pretty much as it was in 2006 when CO2 was about 385 ppm. In other words, the state of sea ice at this time of year – just over 12 million kilometres squared in 2006 and in 2019 – shows no correlation with rising CO2 levels. There is also not a hint of imminent catastrophe for polar bears anywhere within their range, despite the hand-wringing messages from conservation fear-mongers and their polar bear specialist supporters.

As I’ve argued previously (with references), sea ice is a seasonal requirement for polar bears, not a year-round necessity (Crockford 2019).

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Polar bear habitat update mid-May: little change since 1989 despite CO2 increase

Posted on May 15, 2018 | Comments Off on Polar bear habitat update mid-May: little change since 1989 despite CO2 increase

Sea ice habitat for polar bears has not become progressively worse each year during their season of critical feeding and mating, as some scaremongers often imply. It’s true that absolute extent of Arctic ice is lower this spring than it was in 1979. However, according to NSIDC Masie figures, polar bear habitat at mid-May registers about 12 million km2, just as it did in 2006 (although it is distributed a little differently); other data show spring extent has changed little since a major decline occurred in 1989, despite ever-rising CO2 levels.

Polar bear feeding_Shutterstock_sm

In other words, there has been virtually no change in sea ice cover over the last 12 years, despite the fact that atmospheric CO2 has now surpassed 410 parts per million, a considerable and steady increase over levels in 2006 which were about 380 ppm (see below, from the Scripps Oceanographic Laboratory, included in the Washington Post story 3 May 2018):

Scripps CO2 curve at 29 April 2018

Not only that, but if rising CO2 levels were responsible for the decline of sea ice and implied effects on polar bears since 1979 (when CO2 levels were around 340 ppm), why has spring ice extent been so variable since 1989 (when the first big decline occurred) but so little changed overall since then? See the NSIDC graph below for April:

Sea ice 2018 April average_NSIDC graph

This year on day 134 (14 May), global ice cover registered 12.3 mkm2:

masie_all_zoom_4km 2018 May 14

In 2016 on the same day, the overall extent was much the same but there was more ice in the Chukchi and Bering Seas and less in the eastern Beaufort:

masie_all_zoom_4km 2016 May 14

More close-up charts of different regions below for 2018 vs. 2016, showing more detail.

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

Posted on April 30, 2018 | Comments Off on 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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Polar bear habitat update early spring 2018

Posted on April 27, 2018 | Comments Off on Polar bear habitat update early spring 2018

Spring in the Arctic is April-June (Pilfold et al. 2015). As late April is the peak of this critical spring feeding period for most polar bear populations, this is when sea ice conditions are also critical. This year, as has been true since 1979, that sea ice coverage is abundant across the Arctic for seals that are giving birth and mating at this time as well as for polar bears busy feeding on young seals and mating.

Polar_Bear_male on sea ice_Alaska Katovik Regehr photo_April 29, 2005_sm labeled

Below is a chart of sea ice at 25 April 2018, showing sea ice in all PBSG polar bear subpopulation regions:

masie_all_zoom_4km 2018 April 25

Some Arctic subregions below, in detail. Continue reading

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

Posted on May 14, 2017 | Comments Off on 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.

JR1_1266.tif

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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Not much has changed in polar bear country since the sea ice maximum

Posted on May 7, 2013 | Comments Off on Not much has changed in polar bear country since the sea ice maximum

I’ve been busy with work-related activities lately and will be for several more weeks. Until then…

Sea ice changes since March 15 [Update added May 10, see below]

Lots of ice everywhere – even in Hudson Bay. A bit less ice in the Barents Sea (north of Norway) than there was two months ago at the sea ice maximum March 15 (see Fig. 1 below compared to the extent at May 5 in Fig. 2: both from NSIDC). But there is still quite a bit around Svalbard – that group of islands between NE Greenland and NW Norway (see Fig. 3 below a MASIE image, where this situation is more apparent).

Polar bears are eating and mating at this time of year (early May being the tail-end of the season in most areas) – and right now, they have a huge, circumpolar ice platform for those activities.

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