A study published by PeerJ indicated that low frequency noise emitted by cargo ships could be harmful to orcas. Because of this, a group of marine scientists asked the Canadian government to reduce underwater noise in the Salish Sea to protect the orca population in the Pacific Northwest.
The team of scientists from Washington, British Columbia and the U.K., said that noise from shipping vessels and waterfront industry threatened the undersea wildlife, comparing the noise to smog: The way we need to see where we’re going, orcas rely on sound.
“These animals swim around in a kind of acoustic smog, if you like,” Lance Barrett-Lennard, head of Vancouver Aquarium’s cetacean research program, told CBC. “And every ship that goes by absolutely fills their world with noise.”
Southern resident killer whales are endangered in the U.S. and Canada, with only 78 individuals, including only 30 breeding females.
“It’s absolutely a critical time for the survival of that population,” Barrett-Lennard said.
The shipping noise is a problem because it interferes with the whales’ “exquisitely sensitive hearing,” that they use to hunt, navigate and communicate.
“Marine mammals often use sound in the way that terrestrial animals use light, to feel their way around,” Barrett-Lennard added.
According to the Bellingham Herald, the scientists’ letter to Canadian Prime Minister Justin Trudeau specifically recommends reducing shipping noise by three decibels over the next 10 years, and 10 decibels within the next 30. To do so, companies could tweak ship designs and make engineering improvements. They also could set mandatory ship speed limits, among other measures.
“Numerous threats are undermining the population’s ability to successfully recruit new calves, and are threatening its long-term survival,” the scientists said in the letter.
