Tag Archives: ringed seals

Southern Beaufort sea ice melt in May: good news for polar bears or catastrophe?

Last week biologist Andrew Derocher recently implied via twitter that less sea ice in the eastern portion of the Southern Beaufort (SB) this year at mid-May is harmful to polar bears (calling it “a hole in the ice where polar bears used to live“), but both long-term and short-term data don’t support such a glass-half-empty interpretation.

Not only does spring breakup of sea ice in the SB normally begin with such open patches of water (see the video above from last year) — driven by the powerful currents of the Beaufort Gyre, not ice melt (explained in detail here) — it may actually be necessary for the survival of local seals, polar bears and whales in spring and early summer (Citta et al. 2015; Crawford et al. 2015; Harwood et al. 2015; Stirling et al. 1981).

As I’ve pointed out before, the biggest threat to SB bears is thick sea ice in spring and its associated late breakup, a 2-3 year-long phenomenon unique to this region known to have occurred about every 10 years since the early 1960s (well documented in the scientific literature) but which has not (as far as I know) happened since 2004-2006.

In other words, a considerable patch of open water and less concentrated ice in the eastern SB around Cape Bathurst is almost certainly a good thing for this particular subpopulation (see previous post here for an in-depth discussion) because historically, when a polynya of some extent has not formed by April or May it has been devastating for local marine mammals.

The fact that an extensive patch of open water existed at mid-May in this region last year and the year before (2015 and 2016) — with no public hue-and-cry about a great dying of SB bears from Derocher or anyone else — suggests that open water in the eastern SB this year is likely to be beneficial for SB polar bears, or at least benign. Continue reading

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.

Continue reading

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:

crystalball_468x317_predictions_sq

 

“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.

Continue reading

Will Trump reverse ESA decisions listing polar bears & Arctic seals as threatened?

The New York Times reported this morning: “Donald Trump Is Elected President in Stunning Repudiation of the Establishment.”

I’ve never been very interested in politics but this result has me wondering. Could the new president reverse the Endangered Species Act (ESA) decisions listing polar bears and other species as ‘threatened’ with extinction due to future threats from global warming?

future-of-arctic-species-status-under-trump-presidency-9-nov-2016
Continue reading

Recent studies show Sept ice of 3-5 mkm2 did not kill polar bears off as predicted

The annual Arctic sea ice minimum for 2016 is imminent and the hand-wringing about polar bear survival has already begun. While this year is shaping up to be another very low sea ice minimum in the Arctic – not as low as 2012 but lower than as low as 2007 (previously the 2nd lowest since 1979) – contrary to predictions, several recent studies show that such low sea ice coverage in summer has had no (or very limited) negative effects on polar bear health and survival. In fact, for polar bears in some areas low summer sea ice has been quite beneficial (although these are not the populations that polar bear specialists predicted would do better).

polar_thin_ice Jessica Robertson_USGS

Since low summer extents of recent magnitude (3.0 – 5.0 mkm2) are clearly not any sort of threat to polar bears, it seems improbable that even an ice-free (≤ 1.0 mkm2) summer (e.g. Wang and Overland 2015) would be devastating to the species [don’t forget Cronin and Cronin 2016: they’ve survived such conditions before] – as long as conditions in spring allow for the necessary concentrated feeding on young seals.

sea-ice-mins_2007_2012_2015_polarbearscienceAbove: Top, minimum at 2012 (16 Sept, 3.41 mkm2, lowest since 1979); Center, 2007 (18 Sept, 4.17 mkm2); Bottom, 2015 (9 Sept, 4.50 mkm2), from NSIDC. Below: sea ice at 10 Sept 2016, 4.137 mkm2 – minimum not yet called).

sea-ice-extent-2016-sept-10_nsidc

Recall that in 2006, the IUCN Polar Bear Specialist Group based their conservation status of ‘vulnerable’ (likely to become threatened within the next 45 years due to reduced habitat) on the predictions of sea ice specialists (see 2008 update here).

Sea ice experts in 2005 predicted such low summer sea ice extents as polar bears have endured since 2007 (3.0 – 5.0 mkm2) would not happen until 2040-2070, at which time PBSG biologists said that >30% of the world’s bears would be gone.

Evidence to the contrary comes from polar bear specialists working in the Chukchi, Beaufort, and Barents Seas – and in Southern Hudson Bay – since 2007. Overall, the latest IUCN Red Book assessment (2015) put the global population size at 22,000-31,000 (or about 26,500).

All of this means that those polar bear experts were wrong: polar bears are more resilient to low summer sea ice conditions than they assumed.

UPDATE 2 January 2017: I’ve added some quotes from the original USGS reports that explicitly state their dire predictions for 2050 that differ from the predictions made by the IUCN Polar Bear Specialist Group.
Continue reading

Critical spring feeding for polar bears is over – sea ice levels are now irrelevant

Polar bears in virtually all regions will now have finished their intensive spring feeding, which means sea ice levels are no longer an issue. A few additional seals won’t make much difference to a bear’s condition at this point.

Relative importance of seasons polar bear graphic_PolarBearScience_June2016

The only seals available on the ice for polar bears to hunt in early July are predator-savvy adults and subadults but since the condition of the sea ice makes escape so much easier for the seals, most bears that continue to hunt are unsuccessful – and that’s been true since the 1970s. So much for the public hand-wringing over the loss of summer sea ice on behalf of polar bear survival! Continue reading

Tracking polar bears in the Beaufort Sea in April 2016 and early polynya formation

putting_collar_on_polar_bear_slider_USGS

Here’s the update on the polar bears fitted with satellite collars or ear tags in the Beaufort by USGS biologists over the last two years. Five new bears were added last month, which means there are now thirteen bears being tracked. Ice conditions are somewhat different than they have been in the past but concluding that such a situation means trouble is premature, I think (see here). Continue reading