The Arctic’s underwater soundscape signals life. The calls and songs of walrus, bearded seals, narwhals and bowhead whales are bizarrely beautiful and almost otherworldly to our human ears. But for marine mammals, sending and receiving sound underwater is an essential part of life: they use it to find food and mates, avoid predators and navigate the deep, dark, ice-covered Arctic Ocean.
As Melanie Lancaster and Andrew Dumbrille write, anthropogenic (human-made) noise in our oceans affects marine mammals in complex ways, and we need to protect them—now.
Underwater noise can have a range of negative effects on marine mammals. Depending on the source, these can include temporary or permanent hearing loss, behavioural disturbances, displacement and masking (interference with communication). Underwater noise is produced by shipping, seismic surveys (for mineral deposits in the seabed), military sonar and construction, such as of ports and offshore wind farms. It can affect entire species.
Fortunately for the 35 species that frequent the Arctic, noise pollution from industrial activity has been limited in this part of the world until recently. This doesn’t mean the Arctic Ocean is always quiet. It can be quite the opposite—alive with the sounds of ice cracking and shearing, wave action and animals singing. But it is one of the last oceans on our planet that is still largely unpolluted by anthropogenic underwater noise.
However, due to dramatic reductions in sea-ice extent and thickness in the Arctic over the past four decades, Arctic marine biodiversity—relied upon by many coastal Indigenous communities—is now under pressure to adapt. At the same time, desire for unprecedented development of the region is growing. Arctic coastal states urgently need to cooperate on regulating this transboundary pollutant.
Arctic Shipping on the Rise
While management of underwater noise should not be limited to the shipping sector, it is an opportune place to start.
According to a recent report by the Arctic Council, the number of ships entering Arctic waters grew by 25 per cent between 2013 and 2019 while distance sailed jumped by 75 per cent. In addition to existing routes, which will see higher volumes of ship traffic, the Arctic Ocean—once transformed by the climate crisis—could host as many as four new trans-Arctic shipping routes: the Northeast Passage (including the Northern Sea Route), Northwest Passage, Transpolar Sea Route and Arctic Bridge. All offer the appeal of much shorter distances than the two routes that currently connect the Atlantic to the Pacific Ocean (the Panama Canal) and the Indian Ocean (the Suez Canal).
Global policy instruments are in place, that, if wielded effectively, will enable Arctic coastal states to require stronger measures to mitigate underwater noise from shipping. In spring 2021, the International Maritime Organization (IMO)—the global standard-setting authority for the safety, security and environmental performance of international shipping—will consider a revamp of its underwater noise voluntary guidelines. The current guidelines, designed to reduce underwater noise to address adverse impacts on marine life, have neither reduced noise nor compelled the maritime sector to invest in quieter ships. An additional instrument, the IMO International Code for Ships Operating in Polar Waters (the Polar Code), calls on mariners to consider areas known to have dense populations of marine mammals when planning routes.
Both instruments provide opportunities for Arctic coastal states to require stronger measures to mitigate underwater noise pollution from shipping. These measures can be further informed by the Arctic Council’s assessments of underwater noise and its impacts.
Important areas for noise sensitive wildlife
Where there is sea-ice cover, ships will choose routes through open waters for safer and faster passage. But open waters, including leads and polynyas, are hotspots for marine mammals. The Bering Strait is an example: it is part of three out of four possible future trans-Arctic shipping routes—but is also a marine mammal “superhighway” that a million animals use every spring and autumn as they follow the north-south movement of sea ice. The strait is also a marine grocery store for Indigenous coastal communities, who rely on it to feed their families and support their livelihoods.
With trans-Arctic shipping routes anticipated to be navigable by mid- to late century, new measures—such as adjustments to routes and speed limits—are urgently needed to safeguard these important habitats.
Now is the time to address key knowledge gaps about noise-sensitive species, to systematically monitor underwater soundscapes and to manage noise at safe levels. Although monitoring, mitigation and management—the three Ms—can be costly and challenging in the Arctic environment, Arctic coastal states need only look south for inspiration and incentive to act now. In regions where oceans and seas have been exposed to underwater noise for decades, countries are now being forced to adopt noisereduction targets and shoulder the hefty economic costs of mitigation and rehabilitation.
In the Arctic, safeguarding ecosystems, species and the people who depend on them from underwater noise pollution through a precautionary, cost-effective approach is still within reach.
MELANIE LANCASTER is a senior specialist, Arctic species with WWF’s Arctic Programme.
ANDREW DUMBRILLE is a lead specialist, marine shipping and conservation, with WWF-Canada.
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The Arctic Ocean is home to diverse marine species and unique ecosystems, and its cryosphere plays a significant role in moderating the Earth’s climate. The Arctic marine environment also provides cultural identity, food security and a source of income for many of the region’s inhabitants.