Highly Disruptive Human Activity Sounds for “Unicorns of the Sea”

A digitally created image of a male and female narwhal. Photo credit: David Fleetham / VW PICS / Universal Images Group via Getty Images

The Arctic is a vast expanse of blue and white that still holds together in perpetual hushed simplicity. This frozen universe, mostly undisturbed by humans for thousands of years, has retained the pristine calm of Earth when it was born. After millennia of natural protection thanks to its extreme climate, the Arctic has the majesty of motionless peaks, remote places where man rarely goes. Its greatness is exemplified by the creatures that have been shielded from our stormy and destructive wake for so long.

As the Arctic becomes more habitable due to global warming, it also becomes more vulnerable. The region was invaded by equipment for carrying out seismic surveys and mining explosions, not to mention cruise ships, and with them new sounds were introduced – alien sounds in a pristine world. And for some creatures, sound is everything.

In the depths, narwhals hunt – up to 1800 meters, or almost 6000 feet – there is no light, so sound is very important to them. They navigate by echolocation like bats, emitting clicks. From afar, the pounding of human activity can sound like a soft “puh,” like the dropping of a sack of grain, but to narwhals, these sounds are the equivalent of being inside a loud and ringing bell; completely disheartening.

One of the many mystical creatures in this region, the narwhals (monodon monoceros) have a long tusk which has led them to be referred to by some as unicorns of the sea. Their tusk is actually a large tooth with up to ten million nerve endings inside and can grow up to ten feet, according to the World Wildlife Fund. The tusk can be used as a sensory organ for detecting everything from temperature to water pressure and movement, depending on the exchange of local observations and knowledge of the Arctic. It is also flexible and can move about a foot in any direction.

A group of researchers conducted experiments on narwhals showing that the stress response is so extreme to sounds even miles away that it can cause them to stop feeding. The research was published in a paper titled “Narwhals Respond to Ship Noise and Pulses from Air Cannons Embedded in Background Noise,” in the journal Biology Letters.

“The reactions of the narwhals indicate that they are frightened and stressed. They stop making the clicks they need to feed, they stop deep diving, and they swim close to shore, a behavior they usually only display when they feel threatened by killer whales. This behavior means they have no chance of finding food as long as the noise persists,” explained one of the study researchers, Outi Tervo, a marine biologist at the Greenland Institute of Natural Resources, reported Phys.org.

As marine biologist Dr. Susanna B. Blackwell – who is also a research associate at the University of California, Santa Cruz, and a senior scientist at Greeneridge Sciences, Inc. – told EcoWatch, stress responses are normal for humans. mammals in situations where they’re faced with something unknown and disturbing, that human presence and their activities are certainly in the Arctic.

“If you’re eating dinner and suddenly hear a noise that puts you on high alert (like someone is in your garden or house, for example), wouldn’t you stop eating? Narwhals are mammals and we can only assume that they react similarly to other mammals in similar situations,” Blackwell told EcoWatch.

Historically, narwhals have been difficult to study because they live in what is called the High Arctic, a region covered in ice. Researchers tagged members of a herd of narwhals in the Scoresby Sound fjord system in eastern Greenland and exposed them to the sound of a ship’s engine, as well as the sound of a cannon. seismic air. With the help of the University of Copenhagen, the Greenland Institute of Natural Resources (Pinngortitaleriffik) analyzed the research data found through these experiments.

“Our data shows that narwhals respond to noise 20-30 kilometers from a noise source by stopping their clicking altogether. And in one case we were able to measure this from a source 40 kilometers away. It’s quite surprising that we can measure how much something so far away can influence the behavior of whales,” said Susanne Ditlevsen, a professor in the Department of Mathematical Sciences at the University of Copenhagen, who was in charge of the statistical analyzes of the data from research, reported Phys..org.

“Even when ship noise is lower than background noise in the ocean and we can no longer hear it with our advanced equipment, whales can hear it and distinguish it from other sounds in the middle of the ocean. them. And so to some extent their behavior is clearly affected. It shows how incredibly sensitive narwhals are,” Ditlevsen added.

The sensitivity of narwhals to sound may have genetic as well as environmental components. Most of them have never been exposed to the harsh sounds of industrial human activity.

“To some extent, the ability to adapt to a new environment with new sounds probably has a genetic basis. For example, among bird species that can be found in the same environment, some are tolerant of anthropogenic disturbance while others are not,” Blackwell told EcoWatch. “The other factor that plays into narwhals is the fact that until recently, and throughout their evolutionary history, narwhals have been very isolated from sounds and human activities. Therefore, they have had no the chance to develop a tolerance for these sounds and to see them as part of their environment.

Another danger for narwhals is that, as researchers have observed, when whales flee a boat, they do more tail slapping, which drains life energy and oxygen needed to dive to the depths. they make for food, reported Phys.org.

The researchers observed that after a week of sonic testing, the narwhals returned to their normal behavior. But, as Tervo explained, if whales are exposed to disruptive sounds for an extended period of time, such as regular boat traffic from a nearby port, they might have difficulty hunting effectively for a longer period of time. , which “could become quite serious for them”. said Tervo, as reported by Phys.org. “In this case, we are concerned that it could have physiological consequences for them and affect their physical condition.”

Tervo went on to say that the Arctic is changing so rapidly that researchers fear narwhals may not be able to adapt without increased efforts to put protections in place.

“Knowing a species’ sensitivity to disturbance allows management decisions to be made to minimize impacts on whales. For example, disturbing sounds could be restricted to areas or seasons when whales are not present, or to places known not to be important feeding grounds,” Blackwell told EcoWatch.

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