Climate change forcing Bowhead whales to hold off annual migration

Researchers in Canada find that population of Bowhead whale did not make the 6,000km round-trip in 2018-2019. Read more about the whale species here…

Hyderabad: As the ice melts at pace in the Arctic, the mining and shipping industry has carved itself an opportunity out of the crisis. Meanwhile, the marine ecosystem is left to coping with the heat, noise, pollution and the cascade of other changes that come with the upheaval of the environment.

Now researchers have found a whale species that typically migrates away from solid sea ice each autumn and returns every summer to feast on tiny crustaceans did not make the 6,000km (3,700-mile) round-trip in 2018-2019.

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Native species to Arctic

Bowhead whales are one of the few species that reside almost exclusively in Arctic and subarctic waters, thriving within a narrow temperature preference window, generally between −0.5C (32.9F) and 2C.

There are now four different stocks of these whales swimming along in the Arctic — one of the biggest stocks migrate annually from the northern Bering Sea, through the Chukchi Sea in the spring, to the Beaufort Sea where they spend much of the summer before returning again to the Bering Sea in the autumn to weather out the winter.

Factors behind change in migration behaviour

Using data extracted from underwater tape recorders, researchers in Canada concluded that this whale population did not make their annual journey in 2018-2019, they wrote in the journal Royal Society Open Science. Lead author Dr Stephen Insley from Wildlife Conservation Society Canada said it was unclear whether this change was an aberration or the beginning of a new way of life.

The researchers have suggested a plethora of potential factors that could explain what occurred. As water temperatures rise, the proliferation of predators such as killer whales (orcas) could have influenced the bowheads to stay put over winter.

Melting ice ceases migration

If there is absolutely solid ice during the winter, the bowheads would be forced to migrate. They have a huge, thick skull that helps them push through ice up to a meter thick – so they can break even heavy ice, but it needs to be open enough for them to get through cracks to come up to breathe, explained Insley.

Bowhead whales

• The only baleen whale endemic to the Arctic
• Habitat- Median sea ice extent since 1981
• Forages zooplankton and small animals near seafloor
• Known to use their massive heads as ice-breakers
• Can live to be more than 200 years old

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