Harp seals use sea ice as their chilly love nests, and after the lovin’ leads to babies, parents nurse for just 12 days before the pups are on their own. But their ice dens have been melting beneath the baby seals, and when that happens, their chances of survival are slim.
And according to a study published recently in PLOS One, this melting has been happening more and more in recent decades. In 2007, 75 percent of newborn seals off the east coast of Canada died. In 2010, scientists believe almost none survived.
The culprit (as with the so far, but seemingly about to change, warm and dry winter in much of North America), is the North Atlantic Oscillation index, a climate pattern determined by differences in sea-level pressure. When the index is negative, our North American winters are cold and snowy, but conditions across the North Atlantic region from Canada to Russia will be comparatively mild. In 2010 when all the baby seals died, the winter NAO index dropped to −4.64, and ice conditions were the lightest on record in the Gulf of St. Lawrence, a region when harp seals like to hang out.
Weather experts believe that extreme fluctuations in the NAO are caused by climate change. And in the current study, researchers looked at the trend of baby seal deaths in relation to the NAO index over several decades. They performed a retrospective cross-correlation analysis of NAO conditions and sea ice cover from 1978 to 2011 and found that NAO-related changes in sea ice likely contributed to the depletion of seals on the east coast of Canada from 1950 to 1972, as well as to their recovery from 1973 to 2000. Overall, they found that sea ice cover in all harp seal breeding regions has been declining by up to 6 percent each decade since the first satellite data became available.
Though the news isn’t good, National Geographic reports that harp seals are not endangered, and they’re still hunted regularly. But David Johnston, an author on the study, is concerned for their future, since these icy regions are the only birthing grounds they’ve ever known. He tells NatGeo:
We should control what we can control. We can’t control the reproductive biology of seals, or where and how ice forms in their breeding habitats from year to year,” he said. What we can control is human behavior.
Still, if you’re a bleeding heart like me and it kills you to imagine that adorable guy above struggling to survive, learn from our friend baby seal man and don’t be a hero. The pups might be cute, but the adults will kill you.