Have you heard the old adage, “Don’t buy trouble”? I’m thinking we could use a lot more of that attitude from polar bear and Arctic seal biologists these days.
In an interview with CBC News yesterday, Department of Fisheries and Oceans Canada (DFO) seal specialist Mike Hammill fed the fear the media wanted to hear while admitting this year’s low ice levels in the Gulf of St. Lawrence will not affect harp seal numbers significantly (7 March 2016, “Lack of ice means fewer seal pups off the Magdalen Islands this year: Researcher says impact on overall herd limited, but ice patterns over time could be concern”).
And University of Alberta’s Andrew Derocher has been busy tweeting his heart out that slightly lower than average sea ice levels this winter could mean a “challenging” spring for some polar bears – as if spring isn’t always challenging for some bears (especially young bears that are inexperienced hunters and low in the social hierarchy – meaning bigger, older bears often steal their kills – and old bears that are running out of steam).
Here’s what the CBC piece said, which confirms the summary on harp seals as polar bear prey I posted late last month (see satellite photo above for locations mentioned):
“Hammill said the harp seals born in the southern Gulf of St. Lawrence make up only 30 per cent of the overall herd, with most of the pups born northeast of Labrador and Newfoundland. He added that many harp seals that normally birth in the southern Gulf region are making their way northeast to the other areas. [SJC – in other words, when there isn’t enough ice in the Gulf, most of the seals that intend to give birth in the Gulf move into the Labrador Sea or Strait of Belle Isle]
While much of the herd may be migrating, the mortality rate will likely be higher this year for harp seals near the Magdalen Islands. Unlike grey seals that can give birth on shores and islands, harp seals need to have their pups on ice for a month.
“It’s initially for lactation, but also it’s for resting because otherwise they become tired very quickly and then they drown,” Hammill said.
Despite the challenges this year, the marine mammal researcher said it may not have an impact on the herd. But several years in a row of poor ice could have consequences.
“One bad ice year is not that important because you could say it’s mortgaged over several years,” he said. “It’s more when you start to run into a lot of these bad ice years that it might be something for concern.“
Hammill said 2010 and 2011 were bad ice years, 2012 was “OK” and 2014 and 2015 were good years.” [my bold]
So, he’s assuming mortality will be higher than usual even before it happens. And is he really saying that seals can move north when ice is low in the Gulf for one year but not for some unspecified number of years more than one (“a lot”)? It’s never happened yet but he not only assumes it will happen at some point but that when it does, it will be catastrophic? Decide for yourselves what you think of that kind of logic.
As for Derocher, sea ice extent might be a bit lower than usual for this time of year but there is still plenty of ice around and no convincing evidence that a bit less ice than usual in late winter is especially challenging for polar bears (although ice thicker than usual certainly has been catastrophic). The fact is that low ice at the winter maximum is not a predictor for ice extent in late spring or even late summer: 2012 was unusually low because of a particularly strong late summer cyclone that broke up the ice more than usual, which meant more could be transported out of the Arctic – it had nothing to do with ice levels earlier in the year.
Ice levels this year (as of 6 March) are tracking last year quite closely (see graph below, from NSIDC) – and if you’ll remember, 2015 was not a year of catastrophe for polar bears.
In fact, Svalbard area bears were surveyed in August 2015 and found to be in excellent condition, with numbers up 42% over the count done in 2004; a hugely fat pregnant female was spotted in the Arctic Basin.
Despite September ice levels being slightly below average in 2015, at the end of the essential spring feeding period for polar bears (April-June), there was still lots of ice left in the Arctic at 29 June 2015.
Actually, ice conditions in the Gulf and off Newfoundland have improved over the last few days, not deteriorated: see today’s CIS map below and the animated map here to see how much things have changed since the end of February. [Note that most Gulf harps giving birth at the Front (off southern Labrador/northern Newfoundland, as discussed above) means more food for hungry southern Davis Strait polar bears]
Isn’t it time that biologists cooled their spin and stopped buying trouble before it happens? Until they have some actual evidence that polar bears (or harps, or ringed seals) have actually been harmed by lower-than-average sea ice levels in any one season, wouldn’t they sound more scientific if they just kept their mouths shut when the media come begging for sound bites? It’s easy: Just say “no.”
That presumes, of course, that it is the media contacting the biologists and not the other way around.
Sea ice at 7 March 2016 (NSIDC, courtesy WUWT Sea Ice Page):
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