SOURCE: Mongabay
DATE: October 26, 2018
SNIP: Noise from ships changes the way that whales and dolphins communicate with each other, according to two studies published this week.
Marine biologists know that an increasingly cacophonous ocean, filled with the din from shipping, seismic surveys and sonar, is undoubtedly impacting the animals that live there. Loud noises could be damaging the hearing of marine mammals that are dependent on sound as a way of making sense of their three-dimensional world, and sonar blasts have been linked to the mass stranding of whales around the world.
Now, two independent teams of scientists have shown that whales and dolphins alter the sounds that they make in response to the whirr of ships.
The team’s recordings of 26 singing whales revealed that when the ship passed and the singing whales were less than about 1,200 meters (3,940 feet) from the ship, they tended to cut their songs short. What’s more, they often wouldn’t start up again for half an hour. They also weren’t as likely to hang around and sing at distances of less than 500 meters (1,640 feet) from the ship’s path.
The authors of the dolphin study raised similar concerns. In the study on dolphins, the scientists showed that dolphins abbreviated their whistles in response to the sound.
“These whistles are really important,” Bailey said in the statement. “Nobody wants to live in a noisy neighborhood. If you have these chronic noise levels, what does this mean to the population?”
Both teams raised concerns about whether sound in the ocean increases the stress on marine mammals and how it might affect their ability to communicate with fellow members of the same species.