The Canadian government and environmental organizations are pushing to reduce the underwater noise ships create as vessels increasingly travel Arctic waters.
The International Maritime Organization’s sub-committee on ship design and construction this week reviewed its guidelines for the noise generated by commercial shipping, intended to reduce the harm to marine life.
While those guidelines have been in place since 2014, studies indicate they have done little to address the problem, in part because they are voluntary. Meanwhile, the number of ships is growing.
Canada, New Zealand, the United States, and the United Kingdom recently submitted a work plan to the United Nations shipping regulator that recommends updating those guidelines to include a step-by-step process by which ships can be designed or retrofitted to reduce noise, numerical targets for noise reduction, and ways to monitor the problem.
The Clean Arctic Alliance, a group of 21 not-for-profit organizations that has campaigned to ban heavy fuel oil in Arctic waters, called for urgent action.
“There needs to be teeth around the voluntary guidelines. They need to be mandatory,” Andrew Dumbrille, a World Wildlife Fund Canada specialist in marine shipping and conservation, told Cabin Radio.
Underwater noise can come from natural sources like breaking ice or waves, rain, and undersea volcanoes. It’s also generated by human activities like ships, seismic airguns, and drilling operations.
According to Transport Canada, that noise affects more than 130 species worldwide.
Many marine mammals use sound to navigate, communicate, find food and mating partners, monitor their environment, and avoid predators.
Excess noise can interfere with animals’ ability to perceive sounds – known as acoustic masking – and lead to behavioural changes and increased stress. In some cases, it can even cause hearing loss and death.
William Halliday, a scientist at Canada’s Wildlife Conservation Society who researches underwater noise in the Arctic, compared acoustic masking to trying to have a conversation in a noisy room.
“While that may not sound important, that actually has huge implications for certain life stages of marine animals,” he said.
Halliday gave the example of whale calves having difficulty keeping in contact with their mothers. He said that has been associated with the increased mortality of St Lawrence beluga whale calves.
Underwater noise in the Arctic
The Arctic has some of the lowest underwater sound levels on Earth, in part because of limited human activity but also because sea ice has a dampening effect.
Yet the Arctic Ocean is getting noisier every year. Sea ice is decreasing due to climate change and ship traffic is increasing.
Dumbrille said sound travels farther and closer to the surface in the Arctic, affecting birds and marine mammals that travel to the surface to breathe.
Some Arctic species have been shown to react to relatively low levels of noise, indicating they may face more risk than those in non-polar regions.
One study of beluga whales in the Beaufort Sea estimated they could hear an icebreaking ship up to 78 kilometres away.
A spokesperson for Transport Canada told Cabin Radio underwater noise in the Canadian Arctic is an “increasing concern” for the department due to the potential impacts on marine systems and Indigenous ways of life.
Halliday said ship traffic in the region has tripled in the past three decades, though there is limited research on how the associated underwater noise has changed over time.
A report from an Arctic Council working group in April found the number of unique ships entering the Northwest Passage increased by 44 percent between 2013 and 2019. During the same period, the sum of nautical miles sailed in the Canadian Arctic increased 107 percent.
Another study of the Canadian Arctic demonstrated a strong relationship between ship traffic and sound levels. It found sound levels had increased between August and October, and predicted that will expand into July and November as sea-ice loss continues.
How ships can reduce underwater noise
Ships mainly cause underwater noise through propeller cavitation, the creation of vacuum bubbles by propellers. Other sources include the hull, engine, and onboard machinery.
The International Maritime Organization said ways ships can reduce underwater noise include newer propeller technology, wake conditioning devices, and air injection systems. Ship maintenance can also help, like propeller cleaning or work to maintain a smooth hull surface.
Dumbrille said reducing ship speeds and rerouting are also solutions.
The Canadian government and partner non-profits hosted a webinar earlier this month outlining international efforts underway like research on propeller design, propulsion systems, and policies that reduce the threat to at-risk marine mammals.
The European PIAQUO project, for example, looks at retrofit propellers. And the Vancouver Fraser Port Authority has offered substantial discounts on harbour dues to ships recognized as quiet vessels.
One of the challenges of propeller design, however, can be trade-offs between noise reduction and efficiency. Dumbrille said there is a “sweet spot” where propellers can reduce sound while also reducing fuel.
The federal government is now developing an Ocean Noise Strategy to identify and understand stressors and develop and improve mitigation measures. It is expected to be released later this year.
Transport Canada has also launched a $26-million quiet vessel initiative to fund research and development on vessel designs and retrofits that reduce noise.
The department said it is working to understand and mitigate negative impacts on the shipping industry from efforts to reduce underwater noise, including economic impacts and navigational safety.
Efforts in the NWT
In the Northwest Territories, there are other measures in place to reduce shipping’s effect on marine mammals.
A spokesperson for the NWT Department of Infrastructure said Marine Transportation Services pays “careful attention” to protecting marine life, including the use of wildlife monitors on some vessels.
Several marine protected areas in the Canadian Arctic have regulations and guidelines for vessels that aren’t involved in traditional harvesting. They include the Tarium Niryutait marine protected area in the Mackenzie Bay and the Anguniaqvia niqiqyuam marine protected area in the Beaufort Sea.
In those areas, ships cannot approach marine mammals or their traditional harvesting grounds and are prohibited from disturbing, damaging, or removing them or any part of their habitat.
Voluntary guidelines direct ships to avoid certain spots and slow down to a maximum speed of 10 knots in other areas to reduce the risk of disturbing or colliding with bowhead and beluga whales.
Dumbrille said those guidelines were developed in consultation with Inuvialuit communities.