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Understanding the Impact of Climate Change on Northwest Atlantic Harp Seals, Pagophilus groenlandicus


Ice breeding seals such as harp seals require stable ice to give birth and nurse their pups, and for the pups to develop the ability to dive and feed on their own. Photo: DFO

Harp seals, the most abundant marine mammal in the northwest Atlantic, require suitable ice cover for birthing (whelping) and nursing young harp seals. Declining ice conditions as a result of climate change have led to high mortality in young seals. To study the changes in ice suitable for whelping, researchers created models that relate the presence of harp seal whelping patches to the ice habitat conditions in a given area. This was done using data on the location of whelping patches from surveillance flights and survey data, along with ice data (percentage of ice coverage, ice floe size, proportion of open water, and proportion of ice frozen to the shore) from 1969 to 2013.

Results: Researchers determined that harp seals prefer first-year ice and large ice floes over small or medium floe sizes. Because there has been a declining trend in the occurrence of thicker ice and large floes, the findings of this study suggest that the preferred conditions for harp seal whelping sites are at risk.

In another component of this project, researchers studied the dates of ice breakup in the Gulf of St. Lawrence and the Scotian Shelf and found that from 1997 to 2012 the date of ice breakup has shifted from May to March. This change affects harp seals, whose young do not develop full ability to swim until late April. The results of this study will be included in a scientific publication.

Program Name

Aquatic Climate Change Adaptation Services Program (ACCASP)


Atlantic: Newfoundland, Labrador Shelves

Principal Investigator(s)

Garry Stenson
Fisheries and Oceans Canada

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