New Duke University/IFAW study shows harp seals on thin ice
In recent years, the IFAW Seal Team has witnessed firsthand the devastating effects of climate change on harp seal pups in eastern Canada, including dead seals on beaches, abandoned starving pups found on shore, and whitecoat seals crushed to death in ice before they are strong enough to swim. New scientific evidence is proving our eye-witness accounts to be startlingly real and deeply concerning for seal conservation.
A new study shows that warming in the North Atlantic over the last 32 years has significantly reduced the winter sea ice needed by harp seals for giving birth and nursing, resulting in higher death rates among seal pups in recent years.
The study , authored by scientists from Duke University and the International Fund for Animal Welfare (IFAW) and published today in the peer-reviewed journal PLoS ONE, raises conservation concerns for the future of harp seals, which are also commercially hunted for their fur, and to a lesser extent their oil and meat.
Harp seals have evolved to rely on stable winter sea ice as a place to give birth and nurse their young until the pups can swim and hunt on their own. The new study is the first to demonstrate that all four harp seal breeding areas– not just those in the Northwest Atlantic – are being affected by deteriorating ice conditions.
Sea ice cover in all harp seal breeding regions was found to have declined by as much as 6% per decade over the study period. The IUCN Red list of threatened species also notes this concern, stating that “climate change impacts are almost certainly going to be negative for Harp Seals in the future.”
According to the Canadian Department of Fisheries and Oceans (DFO), 80% of the pups born in 2011 were thought to have died due to the lack of ice. 2010 was the year of lowest ice cover ever recorded with coverage at about 80% below the expected levels and 70% of the pups were thought to have died.
Again, in March 2007, extremely poor ice conditions in the Gulf of St Lawrence led DFO scientists to predict that pup mortality in the Southern Gulf could be extremely high, “possibly approaching 100%”.
High ice-related mortality, combined with commercial seal hunts in Canada and Greenland, and bycatch from other fisheries, means that entire year classes of harp seals are likely to be missing from future population surveys.
For example, using the Canadian government’s own estimates, only 600,000 pups were thought to have been born in 2011. If only 20% of these pups survived due to poor ice, 120,000 pups would remain, of which one-third were killed by Canadian hunters. This would leave some 80,000 pups alive to attempt the northward spring migration, where they are subject to bycatch in other fisheries (another estimated 8,500 seal pups killed) and then hunted in Greenland (an estimated 83,000 seals killed).
Clearly these are only estimates and we shouldn’t get too caught up on the numbers, since by using these figures the number of seals estimated killed in 2011 exceeds the number that are thought to have been born!
The point is that entire year classes of pups are being wiped out by a combination of bad ice and commercial exploitation, and not just in one year but perhaps in several years. This fact will not be apparent, however, until at least 5-6 years later, when these pups would have reached breeding age, and their absence will be noticed in the population surveys.
The increased mortality due to lack of ice and reduced reproductive rates has prompted one DFO scientist to recommend a quota reduction for 2012.
Unfortunately, a quota reduction may not be enough. The Environment Canada ice forecast does not provide much hope for harp seals either, predicting yet another below-average ice year, with an ice-free Gulf of St Lawrence and greatly reduced ice off of Newfoundland in the breeding area known as the “Front” in March – the period when seals finish nursing and the commercial hunt normally begins.
With media reports that there are some 400,000 unwanted Harp seal pelts in stockpiles , and the recent announcement that Russia (which makes up 90% of the export market) has now banned the import of harp seal skins , clearly there is no economic reason to continue commercial seal hunting.
Given the continuing cruelty observed during the Canadian seal hunt, the current conservation concerns for the harp seal population, the predictions for yet another poor ice year in 2012, and the likelihood that poor ice years will continue for some time, it seems clear that NOW is the time to end the commercial seal hunt for good. There is no justifiable reason for it to continue, and all the reason in the world why it should end.