Sounds from Human Activity Highly Disruptive to 'Unicorns of the Sea'
At the depths narwhals hunt — up to 1800 meters, or nearly 6,000 feet — there isn’t any light, so sound is very important to them. They navigate by echolocation like bats, by emitting click sounds. From far away, the hammering of human activity may sound like a soft “puh,” like dropping a bag of grain, but to narwhals these sounds are the equivalent of being inside a loud, clanging bell; completely disorienting.
Source: ecowatch.com