Draft Guidelines for Reduction of Underwater Noise from Commercial Ships Approved

Draft guidelines for the reduction of underwater noise from commercial shipping to address adverse impacts on marine life were agreed to by the International Maritime Organization’s Sub-Committee on Ship Design and Construction during its Jan. 23-27 meeting.

The draft guidelines recognize that commercial shipping is one of the main contributors to underwater radiated noise (URN) which has adverse effects on critical life functions for a wide range of marine life, including marine mammals, fish and invertebrate species, upon which many coastal Indigenous communities depend for their food, livelihoods and cultures.

The draft revised guidelines provide an overview of approaches applicable to designers, shipbuilders and ship operators to reduce the underwater radiated noise of any given ship. They are intended, according to the IMO, to assist relevant stakeholders in establishing mechanisms and programs through which noise reduction efforts can be realized.

The draft guidelines revise the previous guidelines, issued in 2014. They include updated technical knowledge, including reference to international measurement standards, recommendations and classification society rules. They also provide sample templates to assist shipowners with the development of an underwater radiated noise management plan.

The draft guidelines are now to be submitted to the IMO’s Marine Environment Protection Committee for approval. The committee is next scheduled to meet July 3-7.

The draft guidelines were developed by a correspondence group with further work completed by a working group which met during the subcommittee session.

The correspondence group was re-established to report back to the subcommittee in January 2024, to address the remaining work under the agenda item.

It was, in particular, tasked with revising a flowchart on the URN Noise Management Planning process to reflect the revised guidelines, and the underwater noise management plan to be used as a tool for raising awareness. The group is also expected to finalize and prioritize a  provisional list of suggested next steps to further prevent and reduce underwater radiated noise from ships.

The subcommittee agreed a work plan which envisages, among other things, identifying ways to implement the revised guidelines and increase awareness and uptake; organizing an expert workshop on potential co-benefits and trade-offs that may exist between the reduction of underwater radiated noise from ships and energy efficiency; and developing a plan of action for further work.

The revised draft guidelines include reference to Inuit Nunaat, the homeland of the Inuit indigenous peoples in Canada saying that, in Inuit Nunaat, a number of characteristics of the region and the activities within could increase the impacts from underwater radiated noise.

This includes potential for icebreaking activities, presence of noise-sensitive species and potential interference with indigenous hunting rights.

“Additional efforts to decrease impacts on marine wildlife are advisable for ships that operate in these areas, including particular attention to reducing the noise impact from icebreaking and implementation of operational approaches and monitoring,” the IMO said in a statement.

Also at its most recent meeting, the working group developed separate draft guidelines for underwater radiated noise reduction in Inuit Nunaat and the Arctic to being utilized in the future by interested parties.

The draft guidelines recognize that Inuit Nunaat is a unique environment and adverse impacts to marine wildlife in this area from shipping noise may be significantly increased as a result. The IMO said that sound levels throughout Inuit Nunaat are lower than elsewhere, making it more vulnerable to increases from industrial activity.