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Mitigating Ocean Noise Impacts on Marine Mammals in Areas Beyond National Jurisdiction

Monday, September 25, 2017
Greta Swanson

Greta Swanson

Visiting Attorney

Humans are rapidly increasing their industrial use of the ocean and its resources, resulting in great increases in underwater noise. Commercial shipping, naval sonar, seismic exploration, pile driving, acoustic deterrents for fishing, and seabed mining all produce ocean noise.

However, the impacts of high levels of noise on both marine mammals and the marine ecosystem as a whole are inadequately understood. Marine mammals, which are highly intelligent and social beings, rely on sonar and hearing sounds for their livelihood. Not only can ocean noise cause marine mammals stress, hearing loss, and an inability to hear certain sounds, it can result in injury or death. It can also interfere with their ability to obtain food, interact socially, and migrate.

Whales are among the species most threatened by underwater noise (Photo: Christopher Michel / FlickR).

Moreover, efforts to regulate ocean noise are just beginning to emerge. Researchers and policy advocates have examined existing legal approaches to regulating noise and its impacts. Some advocate for an entirely new regulatory system, while others suggest modifying existing systems in order to coordinate across sectors and address te issue of noise together with other ecosystem impacts. Meanwhile, existing data is inadequate, and exposure, impacts, and cumulative impacts are little understood. In addition, no single scientific body currently exists to determine impacts, sound limits, and areas needed for protection.

International, Regional, and National Coordination

Marine mammals occupy many areas beyond national jurisdiction, but existing regulatory approaches vary widely in scope and jurisdiction, thereby limiting their ability to adequately address underwater noise. Policymakers, therefore, may want to focus on international legal tools to help mitigate the impacts of ocean noise on marine mammals.

For example, one such tool is the legal framework provided by the United Nations Convention on the Law of the Sea and its sector regulations on shipping, deep seabed mining, and fisheries. International agreement on the measurement of noise can also facilitate the development of regulation. The International Organization for Standardization is in the process of developing measurement standards for noise from shipping, pile driving, and active sonar. And as a step toward implementing its Marine Strategy Framework Directive, the European Union has published monitoring guidance for underwater noise. Also, in 2014, the International Maritime Organization published voluntary guidelines to limit the production of noise from individual ships. However, the guidelines address only a single sector, are not coordinated with other sectors, and do not take into account cumulative impacts.

The United Nations Environment Programme’s Regional Seas Program can also assist efforts to protect ecosystems and biodiversity on a regional level. A few regional approaches have coordinated sector efforts to protect areas within regional organizations’ jurisdiction from the range of possible ocean activities. However, only four of the 18 regional seas programs—Antarctic, Arctic, Baltic Sea, and Northeast Atlantic—currently regulate in areas outside of national jurisdiction. One effort in the Northeast Atlantic coordinates protection across sectors, while the Antarctic has a mandate to protect the marine environment and is authorized to address underwater sound.

There are opportunities to protect marine mammals in particular areas in the ocean. Multiple sectors have tools for establishing and identifying marine protected areas, but their purposes may not be aligned, and few have been used to limit noise. The International Maritime Organization has the authority to designate voluntary Particularly Sensitive Sea Areas to regulate shipping. Regional Fisheries Management Organizations may prohibit fishing in Vulnerable Marine Ecosystems. The International Seabed Authority has been developing regulations that could be used to identify “Areas of Particular Environmental Interest” and “Exclusion Areas” within which mining would be disallowed. Lastly, the International Union for the Conservation of Nature is in the process of identifying Ecologically or Biologically Significant Areas in ocean areas beyond national jurisdiction, under the auspices of the United Nations negotiations toward a treaty to protect such areas. Noise as well as activity limits could be set within any of these marine protected areas.

In addition to international and regional efforts, regulation within individual nations’ exclusive economic zones remains essential to marine mammal protection. In the United States, the U.S. National Oceanic and Atmospheric Administration published technical guidance for assessing the impacts of underwater sound on marine mammal hearing. While the 2016 guidance remains in effect, Executive Order No. 13795, which aims to increase offshore oil and gas drilling and allow increased seismic surveys, has called for its review and potential rescission.

Improved Data & Technology

Environmental impact and strategic impact assessments play an essential role in determining standards, limits, technological requirements, and area regulation, as well as permitting of specific activities. Such assessments must incorporate improved data and science, and account for cumulative impacts on marine mammals and other marine life. Developing uniform standards across industries and activities, which is key to protecting marine mammals, will also require improved data and scientific information.

The use of new technology, such as environmental DNA (eDNA), that can identify organisms present in sea water, together with increased monitoring of sounds produced as well as their impact, could provide valuable data to better inform our understanding of the effect that noise has on marine mammals.

Technological innovations are also important for purposes of improving the practicability of mitigation. Two existing approaches are ship-quieting technology, which also saves energy and emissions, and the creation of sound barriers around high sound activities, such as the use of bubble curtains. Further innovation can help industry adopt practices that better protect marine mammals and other marine life.


In an ideal world, a single international agreement would harmonize regulation of ocean noise. In reality, however, ocean noise regulations are insufficient and impacts on marine mammals are already severe. Concerted efforts to coordinate standards and activities between sectors are necessary to improve mitigation of noise impacts on marine mammals, fish, and other marine life. Moreover, coordinating the use of currently available legal tools could help mitigate impacts more immediately than would negotiation of an international treaty.

All blog posts are the opinion of its author(s) and do not necessarily reflect the views of ELI the organization or its members.