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Why should underwater noise be reduced?

NGOs Call on Shipping Industry to Reduce Underwater Noise to Protect Marine Life


As a meeting of the International Maritime Organisation’s Sub-Committee on Ship Design and Construction (SDC 8) opens today, the Clean Arctic Alliance called on the IMO to take action to ensure that the direct impact of noise from vessels on the health of marine wildlife, including whales, dolphins and fish is meaningfully reduced.

“The International Maritime Organisation must act urgently to protect marine life by revising its guidelines for the reduction of underwater noise,” said Dr Sian Prior, Lead Advisor to the Clean Arctic Alliance. “While the guidelines have been in place since 2014, their lack of uptake and overall failure to reduce underwater noise requires immediate attention. This includes actions that lead to shipping industry-wide measures that significantly reduce the impacts of underwater noise, such as reducing sailing speeds, and the use of equipment such as quieter propellers.”

The agenda of SDC 8 includes several issues dealing with design and construction of ships; agenda item 14 will review the Guidelines for the reduction of underwater noise (MEPC.1/Circ.833) adopted in 2014.

Several countries, along with NGOs, have submitted papers setting out a workplan and discussing the approach to be followed, including the development of comprehensive next steps [3]. The work is intended to identify the barriers to uptake and implementation of the guidelines, as well as the identification of measures that will further prevent and reduce underwater noise from ships.

“The workplan put in place at SDC 8 must be ambitious in scope and reflect the urgency needed to address underwater noise from ships as it continues to increase at alarming rates”, said Sarah Bobbe, Arctic Program Manager, Ocean Conservancy. “Advancements in new technologies such as quieter propellers have already been developed and can be installed on new ships and retrofitted on existing ships when in drydock for repairs. There are also very simple ways to reduce noise, like slowing ships down. This will bring co-benefits of reduced fuel use and emissions.”

“According to a study by Transport Canada, the World Maritime University and WWF the existing guidelines have not been effective in reducing underwater noise, namely because of their voluntary, non-regulatory nature [4]. Research from the Arctic Council has recently shown that Arctic underwater noise has significantly increased over the past few years. Ship traffic is also increasing in the Arctic, and given the unique special Arctic environment, underwater noise from ships has a much higher impact than in other parts of the global ocean,” said Bobbe.

“The Arctic is a special case for underwater noise, as sound travels closer to the surface because of cold temperatures, and also travels much further. Marine mammals frequent the ocean surface and spend time in this Arctic sound channel; and many Inuit communities depend upon these animals for food and their livelihoods”, said Dr Prior.

“Comprehensive next steps are essential to address the delivery of measures which will be effective in reducing underwater noise from ships globally – but this will require sizable ambition from IMO member states. In addition, more stringent regional measures in certain areas, like the Arctic, should be prioritised”, added Prior.

About Underwater Noise:

For many marine organisms sound is the most important means of communication. Under water, vision is very restricted and without good hearing ability, elementary functions such as navigating, finding prey and partners can be hampered. This is of particular importance for marine mammals, and also for fish and even invertebrates.

The Arctic has been almost free of anthropogenic (human-sourced) sound for a long time, but with increased human activity, the Arctic Ocean is becoming more noisy every year. An important source of continuous noise is shipping, more specifically the propeller and the engine. Since shipping has increased substantially during the last couple of decades, underwater noise is becoming an increasing problem, contributing to serious impact on the Arctic ecosystem.

The most important source of continuous underwater noise in shipping is cavitation, or production of vacuum bubbles by propellers. The noise produced by this process leads to masking, where the frequency of ship noise overlaps with sound produced and used by marine mammals.

International Policy

The International Maritime Organization adopted voluntary guidelines for underwater noise in 2014. There are no signs that these guidelines have had any effect and in June 2021 the IMO agreed to “commence further work on underwater noise from ships”. Several member states and NGOs have put in proposals for the review of the Guidelines and information on the reduction of underwater noise and these will be discussed by the IMO subcommittee on Ship Design and Construction between 17 – 21 January 2022.

Since worldwide regulations to mitigate continuous underwater noise by ships are currently not in place, noise mitigation measures are only applied in certain situations or for specific purposes.

The EU, in its Marine Framework Directive has set a descriptor for continuous underwater noise (D11C2): “ ..the spatial distribution, timeframe and levels of background noise is at such a level that it will not have adverse effects on marine ecosystems”.






Article shared by courtesy of the Clean Arctic Alliance Made up of 21 not-for-profit organisations, the Clean Arctic Alliance campaigns to persuade governments to take action to protect the Arctic, its wildlife and its people.

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