Safeguarding marine mammals who spend time in the Arctic

From the elusive narwhal to the charismatic walrus, the Arctic is home to marine mammals found nowhere else on Earth. It’s also a summer gathering place for tens of thousands of whales that make epic migrations from southern locations to feed in the Arctic’s highly productive waters. But as MELANIE LANCASTER and BEN SULLENDER explain, Arctic whales and seasonal visitors to the Arctic face growing threats on their journeys.

EVERY WINTER, PACIFIC gray whales—champion swimmers who hold the record for the longest known mammal migrations on the planet—give birth to calves in the sheltered lagoons of Mexico. In spring, they swim some 11,000 kilometres north to their summer feeding hotspots in the Chukchi Sea. In
autumn, they head south again to repeat the journey in reverse.

Just as Arctic marine mammals need protection in their icy habitats, those whose migrations bring them to the Arctic need to be safeguarded
throughout their long journeys. The International Union for Conservation of Nature recognizes the need to protect the habitats and corridors that whales
and other marine mammals rely on. But how exactly to do this is a new conservation challenge, particularly in the Arctic—and unfortunately, many of the
corridors the whales rely on are poised for significant growth in shipping traffic.

Following environmental cues

While there are still many gaps in what we know about the timing and pathways of migration for Arctic marine mammals, we do know that whales and
walrus migrate according to environmental cues that are at least partly related to sea ice. For example, narwhal in Eastern Canada swim 2,000 kilometres
on return trips between their summer and winter habitats. They closely follow the retreat and advance of the ice edge to stay in the shelter of the sea ice, likely to avoid predation by killer whales.

As Arctic sea ice melts, some species are shifting the timing of their migrations. For example, in 2018, for possibly the first time ever, bowhead whales in
Alaska halted their autumn migration early, remaining north of the Bering Strait all winter.

As animals try to adapt to their changing surroundings, we need innovative, dynamic measures that will give them the best chance of success. Measures to safeguard marine mammals as they migrate should be flexible in space and time. They could include rules such as seasonal fisheries closures, ship speed reductions, or vessel rerouting. The effectiveness of these measures can be greatly improved by local monitoring, better communication, knowledge sharing and cooperation between national governments.

Integrating Indigenous knowledge

There is also great potential for Indigenous and local knowledge to be applied alongside western science to inform many aspects of migration. For
example, the timing of spring migrations for many Arctic whale populations is a critical knowledge gap not easily filled by GPS tracking studies—but
many coastal communities have been carefully observing these migrations for generations.

For migratory species, “home” is many different places. Each year, the Chukchi—the Indigenous Peoples living in Siberia’s Chukchi peninsula—celebrate
the return of the gray whales to the Russian Arctic. When those same whales arrive in Mexico, they are celebrated with an International Whale
Festival. All along their journeys, the whales are enjoyed by whale watchers on the Pacific coast. The world has a shared responsibility to safeguard these
whales and other migratory species at every step of their journeys, from the equator to the Arctic.