Narwhal migration patterns are evolving in response to pressure from changing Arctic conditions, according to a new UBC analysis.
Narwhals are the ideal Arctic mammal for studying migration. These culturally valuable whales are thought to be among the most vulnerable Arctic marine animals to climate change.
They are thought to live for more than a century and are seasonally migratory, with migratory patterns that involve transit from shallow, ice-free waters to wintering sites with more than 95% ice coverage.
Because narwhals may live for centuries, behavioral adjustments may be one of the few options for adjusting to the new normal of a changing Arctic.
narwhals are changing their migration patterns
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The timing of migration appears to be altering over time, coinciding with variations in the region's climate-driven sea-ice loss, as per ScienceDaily.
This study employed satellite measuring devices to examine narwhal behavior, such as when they went into the migratory mode, when they departed summering locations, and how direct their routes were.
Researchers examined satellite tracking data from the Canadian Arctic for 21 years and discovered significant delays in the timing of narwhal autumn migrations, with narwhals remaining longer in their summer areas at a rate of 10 days per decade, according to Dr. Courtney Shuert, lead author and post-doctoral fellow at the University of British Columbia's Institute for the Oceans and Fisheries (IOF).
There were also sex disparities in departures, with male narwhals leaving the summering sites first, while females presumably with dependent young left over a week later.
Narwhals enjoy cold water, and their space utilization is mostly influenced by ice cover and the availability of open water areas.
As a result, narwhals may spend their summers in coastal waters within the bigger summering regions, until ice development in the autumn and an increased risk of trapping compels them to migrate over deeper water to the wintering habitats in central Baffin Bay.
These changes in habit predictability as a result of climate change have resulted in narwhals staying longer in their summering areas, likely adjusting within a single individual lifetime, and will help us better understand how marine mammals in the High Arctic are adapting to climate change, according to Shuert.
"Unfortunately, leaving later is not always good news for the narwhal," stated senior author and IOF associate professor Dr. Marie Auger-Méthé.
Staying at the summering grounds may result in further exposure to shipping traffic linked with the new iron mine, which may not be favorable to the narwhals in the long run.
Climate change and sea ice loss are causing pressures for these species, who are adapting to a new existence in the Arctic.
Natural resource exploitation, ice cracking, and tourism all influence narwhal migration patterns, according to Auger-Méthé.
Climate change and greater human exposure are causing additional stress for these whales, which has ramifications for human activities.
Narwhals, as one of the deepest diving cetaceans, enjoy deep water all year and have been observed at depths of over 1,000 meters, as per Natural World Safaris.
They come at the floe edge in Lancaster Sound and between Bylot and Baffin Islands in the summer and attempt to swim through the ice gaps to their summering habitats in Eclipse Sound, Admirality Inlet, or Prince Regent Inlet.
In September and October, they return to the winter grounds through Baffin Bay and Davis Strait.
The greatest time to observe them is during the summer months, when they pace the floe edge looking for a route deeper in.
The greatest places to watch them are Lancaster Sound and the floe edge between Bylot and Baffins Islands, where groups of one to fifty surface right by the edge of the ice, and you may even witness them making their way up through the gaps in the ice.
They spend their summer and winter grounds in deep water and are difficult to spot.
Narwhal is creatures of habit, and although spending most of their time away from the coast, they return to the same fjords and passes on their passage between their winter and summer homes.
In the winter, they adhere to very deep water, away from rapid ice, and dwell in a very narrow region.
As a result, they may now dive to amazing depths for up to 25 minutes at a time to effectively eat.
They dive between 18 and 25 times each day, spending a significant amount of time deep under the sea during the frigid winter months.
The fast ice around Baffin Island, Bylot Island, and Lancaster Island begins to melt in the spring, as summer approaches.
The narwhal go northwards towards their summer homes, investigating the rapidly retreating floe edge for gaps through which they may make their passage.
This is the greatest time to watch them since they return to the same cracks year after year.
In the summer, they frequently only dive from 30 to 300 meters to obtain food, and they spend much more time at the surface.
It is also feasible to view them at this time. As Autumn approaches, they flee their summer pastures before the quick frost freezes them over.
Unlike in the spring, they spend little time loitering and instead swim quickly to deeper, safer waters.
