A significant drop in maritime traffic brought on by the COVID-19 pandemic has created what scientists call a rare opportunity to study how calmer waters affect resident killer whales on the south coast of British Columbia.
Ocean Networks Canada, which has been monitoring ship noise and sounds produced by marine mammals such as killer whales, said it believes the change will be a blessing to animals.
“The anticipation is that the calmer environment will help killer whales communicate, socialize, navigate and, most importantly, find food,” said Richard Dewey, the organization’s associate director for science.
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COVID-19’s “calmer ocean” could be a boon to endangered killer whales, researchers say
An article published last month in the Journal of the Acoustical Society of America said there has been a 30 percent decrease in commercial shipping traffic to the Vancouver port from China due to COVID-19 in just the first four months of the year. .
Dewey said that not only has commercial traffic been reduced, but there has also been a hiatus in whale watching boats, cruise ships, recreational boats and oil tankers. That led to a noise reduction of
about 75 percent, he said.
“What we are seeing in the Salish Sea are shipping noise levels that have not been around for three or four decades,” he said.
“Then we would have to go back to the 1980s before we had heard such a calm environment.”
One of the main concerns of endangered southern killer whales is that shipping noises have increased and nearly doubled every decade, he said.
These mammals have hearing similar to that of humans, and communicate in a frequency band similar to ours, Dewey said.
They use vocalizations to communicate within the pod, to navigate and most importantly to find their prey, he said.
“They echo to locate their salmon. It is a very sophisticated type of acoustic capacity and the quieter the environment, the more successful they would be at finding prey. ”
In the ocean, Dewey said that whales use sound “continuously and all the time.”
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Their sight helps them see up to a distance of about five to 10 meters, while the use of sounds helps them travel miles, he said, adding that the Salish Sea is a “very cloudy environment.”
Scientists believe that loud human-made noises increase stress hormones in killer whales because they have to yell and cannot communicate over long distances, Dewey said.
He compared it to someone who walks into a noisy club and has to pause until the noise passes, speak louder, or give up.
He pointed out that unlike people in a club, killer whales cannot simply go to a quieter space.
The scientists will use 30 hydrophones to record the sounds of the killer whales as they enter the Salish Sea, which should be any time, Dewey said.
Hydrophones are underwater recording devices that record how loud whales speak when they make noise or just give up.
The team hopes this study will yield much-needed data to make changes to policies and regulations to help animals survive, he said.
“If we see them return and remain in their critical habitat for longer periods … if we have evidence of successful salmon feeding, then those are good signs and, in a sense, calmer environments may only have aided their survival. “, said. .
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The director of the Marine Mammal Research Unit at the University of British Columbia said that in the past, killer whales would be seen in the Salish Sea in May and June, but for the past four years they have been arriving much later, sometimes so late. September.
Andrew Trites said one reason could be that there is not enough salmon, although mathematically there is enough fish for the remaining 72 killer whales in the south.
This has left scientists wondering if the problem is that whales cannot hunt due to disruption of ships, he said.
“And there is an opportunity to see if the whales’ behavior is different with fewer boats in the water and less noise.”
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