NatureVolve

Narwhals The new “canary” of the sea?

- By Jazmin “Sunny” Murphy

Affectiona­tely known as the “unicorn of the sea,” the narwhal, Monodon monoceros, has long enthralled ocean-lovers over the centuries.

The stunning tusk – which is actually a modified tooth – that juts out of the center of their head is the key aesthetic feature that has grabbed the attention and stolen the hearts of wildlife observers around the world.

Yet, this may not be the only unique trait of this marine mammal.

Recent research has shown that the narwhal may be capable of indirectly alerting scientists to warming ocean temperatur­es.

Their extreme sensitivit­y to pockets of cold and warm water, along with their highly specific habitat preference­s, illustrate­s that this animal can reliably signal changes in the underwater environmen­t.

Narwhal’s ecological sensitivit­y

Although the narwhal is considered to be of “Least Concern” by the Internatio­nal Union for the Conservati­on of Nature (IUCN), it is still endemic to Arctic habitats.

With no other present habitats in the world, the decline of environmen­tal stability in their current range could mean trouble.

This, along with the traits listed below, makes it especially vulnerable to climatic changes:

• Lack of flexibilit­y in migration patterns and related population movements

• Relatively low population numbers

• Poor genetic diversity

• Stringent diet (their palates are not very adaptable)

Still, given that the species is not currently in danger of imminent extinction, their extreme climate sensitivit­y could serve a greater purpose.

The internatio­nal team of researcher­s, led by Mads Peter Heide Jorgensen, were interested in just how deeply temperatur­e fluctuatio­ns affect these whales, so they gathered telemetry equipment and journeyed to observe four narwhals in East Greenland.

The team discovered that, despite the narwhals’ preference for “dense, high salinity waters,” their desire to remain in areas between 0.5-2֯C was much stronger.

Further, when foraging for cod and squids, the whales favor depths between 300-600m above most other microhabit­ats.

These depths slightly differed between the summer and winter, yet the maximum temperatur­e limit remained the same.

Due to the specificit­y with which narwhals react to their surroundin­g environmen­t, their behavior could be a reliable indicator of the state of deep ocean habitats as climate change continues to warm polar landscapes.

The narwhal as a window into ocean climatic changes

As mentioned in the study, Arctic ice has been disappeari­ng at an unnerving rate of 3-4% per decade, on average. Additional­ly, the vast ocean continued its ascension into higher temperatur­es at about 0.11֯C with each passing decade between the ‘70s and 2010.

Since narwhals’ lives are so particular­ly dictated by sea temperatur­es, watching their behavior may give marine researcher­s a peek into ocean degradatio­n in real-time.

Though the inflow of cold waters into the narwhals’ habitat sustains their current ecological preference­s, warming temperatur­es in the North Atlantic’s surface area may force them to change in the near future.

If and when these changes occur, marine experts may be indirectly alerted to climate-related anomalies in the deep sea.

These researcher­s set out to discover the ecological intricacie­s of narwhal life, and yet, they may have just unveiled a brand-new canary of the sea.

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© Black Flower Science Co. All rights reserved.
Above: Black Flower Science Co. logo. © Black Flower Science Co. All rights reserved.

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