Marine mammals such as beluga, bowhead whales and narwhals will be at risk as shipping increases through their Arctic habitats – made possible by the shrinking sea ice, a new study has found.
The study, published early in July by the Proceedings of the National Academy of Sciences, was conducted by researchers from the universities of Alaska Fairbanks and Washington led by Donna DW Hauser. It examined 80 sub-populations of the seven main marine mammal groups and concluded that 42 of these populations would be at risk – with the narwhals likely to be most affected. The animals are most at risk during September when the sea ice is most in retreat – last year the first large cruise ship without an icebreaker escort passed along Russia’s Arctic coast and it is envisaged that shipping will be passing over the north pole “within decades”. While the northern sea route is now regularly clear of ice north of the 75th parallel, and for instance on September 4 2017 there were 94 ships in transit along the route, the north west passage remains less used – last year, 2017, 33 vessels made the crossing transit, while 20 had made it in 2012 – more than half of these being yachts.
“We know from more temperate regions that vessels and whales don’t always mix well,” Donna Hauser writes, “and yet vessels are poised to expand into this sensitive region. It raises questions of how to allow economic development while also protecting Arctic marine species.” Hauser also works with local Arctic populations who practise traditional subsistence hunting and who would also be affected by the increased shipping.
Narwhals are especially at risk accoridng to the study because they have very set migration patterns – they use less than a quarter of the Arctic and spend the summer right in the middle of the shipping lanes. Communicating by sound they are described, by fellow author and polar scientist Kristin Laidre, as being: “Notoriously skittish and sensitive to any kind of disturbance.” The researchers identified two “pinch points” – narrow passageways where ships and animals are likely to intersect. These being the Bering Strait that separates the USA and Russia, and Lancaster Sound in the northern Canadian territory of Nunavut. These regions had a risk of conflicts two to three times higher than on other parts of the shipping route.
“These obligatory pinch points are used by migratory species to get in and out of the Arctic, but they are also necessary passageways for vessels using these sea routes,” Hauser says. “Identifying the relative risks in Arctic regions and among marine mammals can be helpful when establishing strategies to deal with potential effects.”
It is hoped that the study will help create guidelines for shipping that can protect mammal populations – avoiding the key habitats and minimising sound disturbances. In May this year the International Maritime Organization published the first international guidelines for vessel traffic in the Arctic Ocean – which will take effect on December 1st 2018. It specifically looks at routing measures and says: “Large vessels will now have lanes charted to modern standards and Areas to Be Avoided that can keep them from navigating too close to ecologically sensitive underwater habitat. These measures will keep vessels on the safest course and reduce the risk of them running aground, colliding, or interfering directly with subsistence hunting.”
From Donna D. W. Hauser, Kristin L. Laidre, Harry L. Stern. Vulnerability of Arctic marine mammals to vessel traffic in the increasingly ice-free Northwest Passage and Northern Sea Route. Proceedings of the National Academy of Sciences, 2018; 201803543
Main photo: belugas in the West Greenland sea ice. Credit: Kristin Laidre/University of Washington