Of all the creatures on the planet, the narwhal is one of the strangest looking. It's a whale which has a large protruding tusk coming out of its head; that's how it got, its nickname, the unicorn of the sea. They live in the Arctic Ocean off the coast of Canada, Russia and East Greenland. However, experts say some populations of narwhal could be extinct by 2025, and it's all because of noise pollution.
Narwhals rely on echolocation, which they use to find food and navigate their surroundings. The animal produces a sound wave which bounces off an object. They pick this reflected sound up through their lower jaw, and information on features like size and speed passes to their ears. However, increase in human marine activity, as well as climate change, has resulted in the Arctic Ocean becoming noisier, which means it's more difficult for narwhals to rely on sound. Susanna Blackwell, who studies the effects of underwater noise on marine animals, told the BBC that there is noisier activity in the Arctic Ocean than ever because, as sea ice melts, new navigation routes are opening. And while icebergs breaking and creaking have been part of the ocean soundscape for hundreds of years, man-made noise is much harder for animals to adapt to, particularly as these changes are so sudden.
Research published inScience Advances in 2023 recorded the reactions of narwhals to the simulated (模拟的) noises of oil expeditions made by a patrol vessel (巡逻船). The scientists tagged and tracked the creatures and found that, on hearing these sounds, they ended deep dives and stopped clicking, the echolocation signal they use for finding food underwater. This is the same reaction narwhals have to orcas, who hunt them, meaning human-made noise could trigger the creature's "threat button".
So, what can we do? Charlotte Findlay, a postdoctoral fellow at Aarhus University, says "noise is actually quite easy to solve. We need to either turn it off or turn it down."
