University of British Columbia engineers are working to help clear up the acoustic smog that hinders endangered orcas' ability to gather information vital to their survival.
Chronic underwater noise from shipping can drown out sounds marine mammals — such as the southern resident killer whales — use and rely on to communicate with each other, navigate, avoid danger or locate their prey.
Concentrated noise in places with lots of vessel traffic, such as the Salish Sea where the southern residents reside, can lead them to avoid areas they go to find food or shelter for their calves. It can also disturb marine mammals’ ability to rest or, in extreme cases, cause temporary or permanent hearing loss.
But the UBC team of engineers is exploring artificial intelligence and other high-tech solutions to tackle the barrage of underwater noise.
Ships’ propellers account for up to 80 per cent of the sound emanating from vessels, said project lead Rajeev Jaiman, an associate engineering professor.
Bubbles not innocuous when it comes to shipping noise
Noise from a propeller can reach 170 decibels — the equivalent of a jet engine or a rocket liftoff, he said, adding such explosive noise travels five times as fast in water as it does through the air.
The noise from ships’ propellers can hit 170 decibels, the equivalent of a jet engine or a rocket liftoff, drowning out marine mammals' ability to safely navigate their ocean environment, say UBC engineers looking to devise solutions to vessel noise.
The culprit is bubbles, Jaiman said.
Called cavitation, high-speed propeller wings churn up the water, causing boils of bursting bubbles that create a popping and high-pitched singing, which can disrupt marine life within 100 kilometres.
The team is looking at new ways to design and manufacture ships and their component parts, Jaiman said, such as testing propellers with wavy, serrated edges to change the flow patterns that cause noise.
The researchers are working with industry partners such as Vancouver’s Seaspan Shipyard and two naval design firms to create or test new innovations, he added.
Machine learning to protect marine creatures
Artificial intelligence and machine learning are also a big part of the research effort, said co-lead Jasmin Jelovica, a naval architect and assistant professor.
Developing and using AI allows researchers to run ship design and manufacturing simulations in a fraction of the time involved in traditional computational methods — where a human uses a computer to problem-solve, Jelovica said.
“Modelling even a tiny proposed structural change can take weeks. With AI, that work can be done in a matter of seconds,” he said.
The team also got funding from Transport Canada’s Quiet Vessel Initiative to build a machine learning-based noise-prediction toolkit.
The AI system will help ship commanders adjust vessel operations in real-time by analyzing the location of marine mammals and other input variables such as shipping traffic, marine environment conditions and alternate routes to reduce noise issues.
Vessel traffic, should the Trans Mountain oil pipeline come online, is expected to increase seven-fold in the Salish Sea, which includes the Georgia Strait.
Unabated, vessel noise will increase the risk of extinction for the 73 southern resident killer whales that lived in the area as of September.
But shipping volumes, the associated noise and the potential harms to marine life are on the rise worldwide, which means the race is on to resolve the issue, along with limiting greenhouse gas emissions from vessels, Jaiman said.
The International Maritime Organization is in the process of developing guidelines to reduce underwater noise from shipping, and thresholds are likely to be established in the next couple of years, he added.
“It’s a very hot topic for research, and Canada is leading the way,” Jaiman said.
But the engineering team is also relying on collaboration with experts from UBC’s Marine Mammal Research Unit, he said.
It’s important to understand which noises or frequencies cause the biggest impacts or behaviour changes in whales or other marine mammals so engineering solutions can be designed accordingly, he added.
“The marriage of biology and engineering is important here,” Jaiman said.
“We all want to work together to address this problem in a unified way.”
Rochelle Baker / Local Journalism Initiative / Canada’s National Observer