A recent spike in beluga deaths in Quebec’s rivers is being linked to noise pollution. Researchers with Tadoussac's Group for Research and Education on Marine Mammals (GREMM) are investigating the origin of the increase.

Ferries, ships, and boats in the Saguenay and St. Lawrence rivers are potential culprits. Researchers are basing their findings on the theory that beluga calves have soft calls which can be easily overpowered. As a result, calves and mothers are getting separated, jeopardizing their ability to survive.

According to Peter Scheifele, professor at the University of Connecticut, the amount of sound boats generate is harmful even for humans. "In fact, the noise of boat motors in certain areas of the St. Lawrence is so loud that, if humans were exposed to the same sound levels, they would be required to wear safety equipment," wrote Scheifele in a 1998 article.

Too noisy

Of the 14 carcasses found in 2015, six were newborn calves and three were pregnant. The year before, 11 carcasses were found, six of which were also babies. In 2013, four of the 17 carcasses were babies. These findings are the grounds for GREMM's theory, which theorizes Quebec's loud Saguenay River is too noisy to belugas to communicate with each other.

According to the director of GREMM's marine research group, Cacouna -- roughly 200 km north of Quebec City -- has seen an increase in traffic, which could explain the impact on mothers and their calves. Utilizing drones and underwater microphones, GREMM will be investigating the context in which calves call out and how much the calls are muffled by marine transportation.

Primarily an arctic species, the St. Lawrence Estuary beluga population is at the southernmost limit of its range and geographically isolated from other populations.