Noise pollution is killing whales, but this technology can help

But even into the last century, humans did not know the soundscape beneath the waves. Unable to hear the low frequencies that go the farthest underwater, explorers and scientists thought the ocean was a “silent world,” according to French bioacoustics expert Michel André.

“We (humans) neglected that acoustic dimension,” he says. “We polluted the ocean with sound, without even having the first idea that it could do harm.”

In recent decades, the ocean depths have become noisier, with the rumble of ship engines, the intense pulses of military sonar, and the seismic blasts used to locate oil and gas deposits. This cacophony of man-made sound is drowning out the natural chatter of marine life, and the impacts are life-threatening.

Mammals such as whales have been isolated from their mates, migration routes have been disrupted, and in some cases noise pollution has caused permanent, potentially fatal, hearing loss.

“Sound is life in the ocean,” says André. “If we pollute this channel of communication … we are condemning the ocean to irreversible changes.”

André and other scientists believe that increased noise pollution has led to more collisions between ships and whales, as the ocean giants — which use echolocation, or biological sonar, to “see” objects — can struggle to locate a ship over the constant hum. some people have become so deaf that they do not hear the approaching danger. Since 2007, the International Whaling Commission has recorded 1,200 ship-whale collisions worldwide, but many more may go unnoticed.

Safe and quiet

Technology that uses acoustics to detect the presence of whales in shipping lanes can help prevent these collisions. André and his team at the Laboratory of Applied Bioacoustics in Barcelona have developed software called Listen to the Deep Ocean Environment (LIDO), which monitors acoustic sources in real time and uses artificial intelligence to identify them.

In October, a two-meter buoy equipped with this technology and other sensors will be dropped in the Gulf of Corcovado, off the coast of Chile, in an area full of whales and ships. Using LIDO, it will be able to detect whales within a radius of at least 10 kilometers and will automatically send an alert to the Chilean navy, while also sending a message to nearby ships, prompting them to change course or reduce speed. Boat engines make less noise at lower speeds, which makes it easier for whales to home in on their location.

The buoy will be the first of a wider network deployed as part of the Blue Boat Initiative, a program created in 2020 by the MERI Foundation, a scientific research organization based in Chile. The long-term goal is to have these types of buoys run along the coast of South America and beyond, providing safe passage for migrating whales and other marine species, says MERI Executive Director Sonia Español-Jiménez.

The Gulf of Corcovado was an obvious place to start. The body of water, which stretches more than 50 kilometers between the island of Chiloé and the southern Chilean mainland, is a whale habitat — home to nine species — and the largest feeding ground in the southern hemisphere for the endangered blue whale.

But the area is also subject to heavy maritime traffic, as there are many salmon farming vessels. However, studies conducted in the US have shown that reducing the speed of ships is a simple and cost-effective method to avoid collisions with whales.
The noise from the ships' engines can disorient the whales, who rely on sound to navigate.
In May 2021, after deadly collisions off the coast of Chile, more than 60 Chilean scientists made a plea to the government to divert ships from sensitive regions, to set speed limits on certain shipping lanes and to establish an alert system to warn ship pilots.
Susannah Buchan, research associate at Concepción University in Chile, was one of the signatories and is currently working with the Woods Hole Oceanographic Institution (WHOI) to adapt a similar acoustic warning system for Chilean waters. WHOI technology has already been deployed in the Santa Barbara Channel, off the coast of California and off the coast of Savannah, Georgia.

While he sees “a lot of potential in acoustic alert systems,” Buchan says it’s important to have them fully validated in the scientific literature and through a peer-review process. He also warned that acoustic warning systems are not the “silver bullet” that will end all ship attacks and should be complemented by other solutions, such as deceleration zones.

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Understanding the ocean

The acoustic buoys deployed as part of the Blue Boat Initiative will not only act as an early warning system for ships, but will also use sensors to collect data such as water temperature, pH and oxygen levels, which can be used to analyze ocean health and ocean health. the impact of climate change.

They could also be used to help control local whale populations. “Each whale has a unique sound,” Español-Jiménez explains, and the buoy’s LIDO technology can identify and classify four species of whales found in the Gulf of Corcovado from their song — humpbacks, blue whales, whales and whales. He added that as the buoy collects more data, LIDO can be trained to identify other marine species.

All this data together can be used to inform government policy and action on marine conservation and climate change, he said.

Technology is transforming our understanding of the ocean, says André. “He’s regained that ability to listen underwater and to hear the underwater creatures and understand their need to survive in this environment.”

A pioneer in bioacoustics, André’s work began in the 1990s when he began investigating the cause of ship-whale collisions on a busy ferry route in the Canary Islands. His research found that exposure to noise in whales caused “acoustic trauma”, and their inner ear receptors became severely damaged over time.

That’s when he had the idea to create an acoustic system to protect whales from colliding, but the Blue Boat Initiative is the first time his technology will be implemented in the real world.

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André would like to see it spread more widely, crossing countries and continents. “My hope is that we can replicate this effort along the Pacific coast to cover the tracks of these whales all the way to Alaska,” he says.

By offering tools to identify sound sources and monitor biodiversity, André believes that humans can reconnect with nature and help restore it: “If we can find a way to control, hear and understand the message of sound, then we have it. A way to understand the state of the health of the earth.”