First Global Review of Arctic Marine Mammals Reveals Uncertain Future

Picture of a polar bear
A young polar bear comes to shore during the summer in northern Alaska. (Photograph by Eric Regehr, U.S. Fish and Wildlife Service)

Despite Arctic marine mammals being icons of climate change, little is known about their populations across the Arctic. In a first ever global review of Arctic marine mammals, published last week in Conservation Biology, an international team of scientists provides a circumpolar range assessment. They studied population status and trends for 11 species, including polar bears, ice seals, narwhals, and walruses.

The scientists also measured changes in sea ice habitat and recommended conservation priorities for the future. National Geographic spoke with lead author Kristin Laidre of the University of Washington’s Polar Science Center about the team’s findings.

Why is it so difficult to get data for Arctic marine mammals?

The Arctic is inherently a difficult place to work. You’re dealing with extreme weather conditions that make operations challenging. It’s also very expensive, and Arctic surveys require enormous resources. For many of these species, their populations have never been surveyed.

Arctic marine mammals are also wide-ranging. They move over hundreds of square kilometers and across international borders. This makes surveys difficult and requires time, resources, and often international collaboration.

What trends did you find in sea ice habitat loss?

The timing of sea ice formation is critical for most species because their life events, like feeding and reproduction, are timed with specific weeks of the year when there is sea ice present. We conducted an analysis to examine changes in the timing of the spring sea ice break-up and the fall sea ice freeze-up. This estimated the total number of weeks of the summer—low ice—season, during which the ice is relatively open. In almost all areas, the duration of the summer season has increased by five to ten weeks since satellites started recording —> Read More