Huge data gaps cloud fate of Arctic mammals
A first-ever effort to gauge the ecological status of all 11 species of marine mammals living in the Arctic reveals a mixed picture—and a lot of missing information. Researchers found that although some populations appear to be coping with climate change, others are in decline. Overall, however, scientists found that little information is available on most of the 78 known populations.
“Unless we fill critical data gaps, this is the information we have to base management decisions on for the foreseeable future—amid increasing development pressures,” says Kristin Laidre, the study’s lead author and a marine mammal biologist at the University of Washington’s Polar Science Center in Seattle.
Laidre’s team looked at what is known about marine mammal populations that play a key role in Arctic ecosystems and human communities, focusing on polar bears, beluga whales, narwhals, bowhead whales, walrus, and six different seal species. Many of these animals are fierce predators that sit atop the food web, but Laidre’s team found that they are also important subsistence resources: Arctic people hunt nearly 80% of the studied populations for food and other uses. “In modern times, there are few other places in the world where wild top predators support humans,” Laidre notes.
Some of these populations appear to be in danger, concludes the study, published online today in Conservation Biology. Overall, eight subpopulations show signs of decline, including some groups of polar bears and seals that depend on winter ice for feeding and reproduction. Satellite data show that, between 1979 and 2013, the summer ice-free season expanded by an average of 5 to 10 weeks in 12 Arctic regions, with sea ice forming later in the fall and melting earlier in the spring. Summer is 20 weeks longer in the Barents Sea, a warming hot spot along the northern coasts of Norway and Russia.