What would more tanker traffic on the St. Lawrence mean for endangered belugas?

nergie Saguenay, a proposed $14-billion pipeline and LNG terminal, is the largest private investment project in recent Quebec history. CBC Quebec travelled through the region to find out what's at stake. Here is the final installment.

• Read the whole series here

Michel Moisan stands at the stern of the Bleuvet, an eight-metre-long boat, the Tadoussac harbour at the mouth of the Saguenay River off in the distance.

Out here in the St. Lawrence Estuary, the water is flat, the colour of blue satin. Gazing below the surface, everyone aboard can just make out long, half-moon shapes outlined by turquoise. As they move closer to the surface, those shapes become white and more distinct.

A pod of curious belugas is following the boat.

Moisan holds out a long pole. Attached to it is an orange and navy device about the size of a bath toy, with suction cups underneath.

Moisan looks like a soundman on a film shoot, about to interview one of the playful animals with his boom mic. What he's really trying to do is stick the device, called a DTAG, to the back of one of the belugas.

It's no easy task. The animals surround the Bleuvet, swimming in parallel to the boat, then trailing behind, ducking beneath and swimming ahead again before disappearing.

Moissan, a wildlife technician for the Group for Research and Education on Marine Mammals (GREMM), will try three times to tag a beluga before succeeding, at last in the late afternoon. He watches the whale dive below the surface, the tag on its back.

The tag will remain stuck there for less than an hour, recording the sounds the beluga makes, what it hears and other ambient noise, and tracking other data in high resolution, including the depth the beluga swims to and the speed at which it travels.

Only scientists on approved research missions are allowed to get this close to belugas, here in the Saguenay-St. Lawrence Marine Park.

At the helm of this missionis Vronique Lesage, a Department of Fisheries and Oceans research scientist, who is collaborating with GREMM to study how noise affects belugas.

It's critical and timely work.

There are several industrial projects on the horizon which, if they proceed, will double marine traffic through the marine park and in and out of the Saguenay Fjord.

One of them, nergie Saguenay, hopes to get approval by 2021 to extend a pipeline to the Port of Saguenay and ship out liquefied natural gas for export overseas.

If the project goes ahead, tankers as long as three football fields will pass through the belugas' territory. Researchers want to know the impact of the noise from that increased marine traffic on the belugas' health.

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Belugas communicate and navigate using echolocation. They use sound to understand space and dimension, and to find food.

"Their world is acoustic," says Lesage.

As a graduate student in the 1990s, she studied the belugas' reactions in the presence of ferries and smaller craft, learning how noise can mask some sounds and make communication trickier.

It's similar to how humans respond when they're in a noisy bar.

"They will repeat themselves. They will simplify the message," Lesage says. "They will talk with a high-pitched voice."

If it becomes too loud, belugas will simply go quiet.

"They wait until the boat passes by, and then they start again."

"If you raise the ambient noise, what you do is reduce their world to a smaller area," Lesage says. "It can, in fact, interfere with their communication with other pods of belugas that are around or can make the capture of food more challenging."

Does noise affect beluga reproduction?

Lesage's current research is a multi-year project under the federal Ocean Protection Plan announced in 2016. She's trying to pinpoint how noise levels impact behaviour and whether that could have an impact on the whales' ability to reproduce.

Estimates put the St. Lawrence-Saguenay beluga population at just 900 animals. They're listed as endangered under the Species At Risk Act, as well as by the Committee on the Status of Endangered Wildlife in Canada.

The beluga was first listed as endangered in 1983. It has been relisted several times, notably after a huge spike in deaths among newborn calves and pregnant females between 2010 and 2012.

Marine biologist Robert Michaud, GREMM's scientific director, said those deaths signalled that the belugas, which had been coping with marine contaminants for years, were clearly facing a new threat.

"We don't know exactly what it is," Michaud said. "Among those hypotheses that have been targeted, noise and disturbance is a key element."

Michaud says it takes decades to clean up polluted waters or to rebuild fish stocks that belugas feed on.

But he suggests curbing noise is something that can be done right away to the benefit of belugas.

Bubbles and other ways to make quieter ships

The proponents of nergie Saguenay believe gaining approval for the natural gas liquefaction plant and marine terminal doesn't mean condemning the belugas to a noisy existence.

"Our objective is really to minimize everything we can on subaquatic noise, and based on our studies, our impact will be very well mitigated," said Pat Fiore, president of GNL Qubec.

He says the company has hired ship designers to look at how to make quieter vessels everything from incorporating a double-hull design to absorb sound and a double-propeller system to reduce the rotation of water, to systems that would stifle motor noise.

Then there's something called bubble technology.

"Basically, you inject air bubbles at the front of the ship, and it goes under the hull and creates like a blanket of air that reduces sound and friction," explains Fiore.

GREMM's Michaud is skeptical.

"I don't think it's fantasy," he says. "But we have no demonstration that this can work."

He says all mitigation options, including the bubble clouds, should be considered. But the decisions should not be made before there is more science gathered on the threat of noise on belugas.

"If we go ahead with that, before validating these concerns, we might lose one of the best conservation options we have to help the beluga population, which is the protection of acoustic refuges."

Protecting the belugas as a litmus test

In his role as scientific director of GREMM, Michaud does not take a hard position on the LNG project. He says noise and disturbance are real threats to the beluga population, but he says those threats are manageable.

"I never thought that the LNG project will kill the beluga whale population. Belugas have been travelling around boats and have been exposed to noise for decades now."

But as an individual, he says he's concerned about more fossil fuel development on the future of the planet.

"I think the biggest question is definitively turned around its impact on climate change," Michaud says.

Michaud, who has spent 35 years studying the beluga, looks back on nearly four decades of conservation measures brought in to protect the marine mammal since it was first listed as endangered.

"The success of all these efforts is not only important for the belugas themselves," he said. "I think it's important for us."

He says people have to ask themselves, "Are we able to share the planet with others and the belugas?"

"It is a good challenge for us. If we're not, I think we're screwed."