Researchers study how ocean noise affects endangered North Atlantic right whales
Saving the species means looking beyond just stopping mortalities, scientists say
Researchers are trying to better understand how noise in Atlantic Canadian waters is affecting the endangered North Atlantic right whale.
Clair Evers, a biologist with Fisheries and Oceans Canada based in Halifax, is focusing her research on "upcalls" — a contact call used by both males and females.
But scientists believe that increased ocean noise such as shipping sounds, oil and gas activities and even environmental factors like loud wind and rain can make it difficult for the whales to communicate.
"We found that when whales are exposed to higher noise levels, they actually call louder," said Evers, based out of the Bedford Institute of Oceanography.
"If you're yelling louder to try and get your voice heard, it's probably using more energy, so we really want to measure just how often this is happening and how much louder they are having to call."
There are just 356 North Atlantic right whales left in the world, according to recent estimates.
Since a large number of right whale deaths reduced the already dwindling population in 2017, Canada's federal government has taken measures to prevent ship strikes and fishing gear entanglements.
But when it comes to making sure the species can truly recover, Andrew Wright, a researcher with DFO, said governments and scientists have to look beyond deaths.
"We still have to deal with the other side of the equation, which is making sure they are healthy enough to reproduce fast enough to replace the animals that have been lost," said Wright.
"That's where the noise comes in. Noise and other human stressors, very much like in humans, can influence the health of the animal. And that in turn has a knock-on effect on their ability to reproduce."
Wright is also the lead researcher for the Marine Environmental Quality program in the Maritimes, one of three regions studying the impact of noise on ocean species under the federal government's Ocean Protection Plan.
Evers's research is one of several projects happening around noise and the right whales. She said previous research has shown the whales change their tone to try and reach one another in noisy waters.
"Then if the noise is getting louder, how much are they able to compensate? How much louder in tone and level can they go?" Evers said, adding that there may also be long-term effects from calling louder for longer.
"That's definitely something we want to look at. Maybe it's also that they could call less as well, like if it's really noisy, maybe they stop calling."
Evers said the underwater hydrophones sit on the bottom of the ocean for a year at a time.
So far, they have looked at calls in Emerald Basin, but they are preparing to look at data from Roseway Basin, Grand Manan Basin and other spots along the Scotian Shelf, which will also give them a better understanding of where the whales are moving.
Other research being done includes how the stress hormones impact the whales' body tissues to understand the more subtle effects of noise and other stressors.
Wright said they will be gathering data for about another year, before they can move to the analysis phase.
"Then we'll be working very hard to compile all of this research to draw out conclusions that can help politicians and the managers make more informed decisions about what might need to be done to give these whales a little bit more acoustic space."