An international team of scientists is preparing to trap a dozen baleen whales off the coast of Norway and conduct hearing tests on them to gauge their sensitivity to human-made sounds such as sonar.
Researchers have tested the auditory faculties of smaller animals in captivity, but this would be the first time scientists have ever captured live whales in the wild to assess their hearing.
“This has been a long-standing issue, this lack of information on how sensitive the hearing of these large whales is,” said the project’s principal investigator Dorian Houser, of the National Marine Mammal Foundation.
“We’re trying to get the first measurements to empirically show what they hear and how sensitive to sound they are,” he said.
The goal of the project, which was initiated and is partly funded by the U.S. government, is to use what they learn to regulate human-generated noise in the waters where these whales swim. It could have implications for the military as well energy companies.
The research effort is in hot water
The study has already generated a wave of pushback from some scientists and environmentalists who believe it puts the whales at unnecessary risk.
A letter to Norway’s prime minister Erna Solberg signed by 50 scientists from across the globe suggests the trapped whales could become stressed or even injured, possibly resulting in long-term harm.
“[T]he safety and welfare risks (for both humans and whales) are too great: it is simply not possible to guarantee that entrapped minke whales can be handled in a manner which is safe for all those involved,” the letter warns.
A petition urging the Norwegian government to stop the tests has garnered more than 60,000 signatures.
But Anne-Lise Hammer, communications director at Norwegian Defence Research Establishment, said requests to stop the test have been denied by the Norwegian Food Safety Authority, or Mattilsynet, the agency that approved the scientists’ initial application.
How the whales will be trapped
Researchers plan to trap the young minke whales as they travel between two small islets in the fjord off Vestvågøy, a municipality in the Lofoten Islands. The whales will then be moved into a modified fish farm.
From there, any animals approved for hearing analysis will be hoisted into a hammock-like net and go through up to six hours of AEP (auditory evoked potential) testing, which involves measuring nerve signals sent through electrodes.
A previous attempt to catch baleen whales for hearing tests in Iceland failed because the whales were able to escape, Houser said.
The minke whales in the Norway study will be satellite-tagged before they are released, and none will be in captivity longer than four days.
Although Houser acknowledged that the project posed a risk to both the whales and people involved, he said the scientists would monitor the heart and respiratory rates of the whales and collect blood samples to ensure they remain healthy. According to the application, researchers could also sedate the whales to reduce stress.
“What we know about that kind of thing with dolphins, with recent work, is that as soon as you relieve the stressor then they tend to come back to a normal physiological state fairly quickly. That’s our expectation with these animals as well,” Houser said.
“Their welfare is our primary concern,” he added, noting that the point of the study was to reduce any harmful effects of noise on baleen whales in the future. “In our minds, that’s a conservation issue.”
Houser said they began the study one week ago following delays caused by COVID-19 but they are still in the preparation phases and have not yet trapped any whales.
How the U.S. government is involved
Although the research team includes both American and Norwegian scientists, it was the U.S. government that spurred on the study in the first place.
Houser said there had been concerns for years about the effects of military sonar and seismic surveys by oil and gas companies on large whales, but scientists knew little about their hearing.
The $1.8 million research project is being conducted for The Subcommittee on Ocean Science and Technology.
Houser said the organizations funding the study included the U.S. Navy, the Bureau of Ocean Energy Management, NOAA Fisheries, and the Marine Mammal Commission.