Marine Mammal Acoustics in a Noisy Ocean: Understanding the Impacts and Mitigation Strategies
The ocean, a realm of mystery and wonder, is increasingly becoming a noisy environment, posing significant challenges to its inhabitants, particularly marine mammals. This article delves into the intricate world of marine mammal bioacoustics, exploring the sources of underwater noise, its effects on marine life, and the ongoing efforts to regulate and mitigate these impacts.
The Noisy Ocean: Sources of Underwater Noise
The ocean's soundscape is shaped by both natural and anthropogenic sources. Our book explores the fundamentals of ocean acoustics, revealing the intricate sources of underwater noise that challenge marine life. Humans are rapidly increasing their industrial use of the ocean and its resources, resulting in great increases in underwater noise.
Marine mammals, 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.
The Impact on Marine Mammals: Physiology and Behavior
Readers delve into the unique vocalizations of mysticetes, odontocetes, pinnipeds, otters, and sirenians, uncovering their diverse communication in stormy waters. The book presents research on marine mammal hearing and the impact of noise on their physiology and behavior, from the subtle behavioral responses to the broader biological significance of these effects.
However, the impacts of high levels of noise on both marine mammals and the marine ecosystem as a whole are inadequately understood. Meanwhile, existing data is inadequate, and exposure, impacts, and cumulative impacts are little understood.
International and Regional Regulatory Efforts
Moreover, efforts to regulate ocean noise are just beginning to emerge. 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.
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.
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.
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.
Marine Protected Areas
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.
National Regulations and Technological Innovations
In addition to international and regional efforts, regulation within individual nations’ exclusive economic zones remains essential to marine mammal protection. 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. 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.
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.
The Path Forward: Harmonization and Coordination
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.
Existing Regulatory Approaches to Ocean Noise
The following table summarizes the existing regulatory approaches to ocean noise:
| Regulatory Body | Area of Focus | Tools for Regulation |
|---|---|---|
| United Nations Convention on the Law of the Sea | Shipping, deep seabed mining, fisheries | Legal framework |
| International Organization for Standardization | Shipping, pile driving, active sonar | Measurement standards for noise |
| European Union | Underwater noise | Monitoring guidance |
| International Maritime Organization | Shipping | Voluntary guidelines to limit noise |
| United Nations Environment Programme’s Regional Seas Program | Ecosystems and biodiversity | Protect ecosystems and biodiversity on a regional level |
| International Maritime Organization | Shipping | Designate voluntary Particularly Sensitive Sea Areas to regulate shipping |
| Regional Fisheries Management Organizations | Fishing | Prohibit fishing in Vulnerable Marine Ecosystems |
| International Seabed Authority | Deep seabed mining | Identify “Areas of Particular Environmental Interest” and “Exclusion Areas” within which mining would be disallowed |
| International Union for the Conservation of Nature | Ocean areas beyond national jurisdiction | Identifying Ecologically or Biologically Significant Areas |