What Is Ocean Noise?
Marine mammals and other aquatic animals have evolved over millions of years to use underwater sound as a primary means of communicating and assessing their environment. Sound plays an essential role in critical activities for marine species, like breeding, foraging, maintaining social structure, and avoiding predators. For instance, cetaceans (whales, dolphins, and porpoises) send and receive complex sounds to communicate with each other, navigate the water, find food, and more. Fish and invertebrates also use sound for these basic life functions.
Since the beginning of the industrial age, humans have introduced increasing amounts of sound into the oceans. Wide-ranging activities, such as global shipping, oil and gas exploration, construction activity, and naval exercises, contribute to ocean noise. Potential effects of these human-made sounds may range over wide spatial and temporal scales because sound travels so well and much farther than light underwater.
Why Is Ocean Noise Important?
There has been growing concern over the potential impacts of ocean noise on the efficiency of sound traveling underwater and the overall wellbeing of marine species. Depending on the sound source, duration, and location, human-caused sound can affect animals by:
- Causing temporary or permanent hearing loss
- Causing a stress response
- Forcing animals to move from their preferred habitat or divert from their migratory path
- Disrupting feeding, breeding/spawning, nursing, and communication behaviors
The impacts may be immediate and severe, or they may accumulate over time. NOAA scientists research the effects of sounds made by human activities on marine mammals’ abilities to “hear” and navigate the ocean environment. They use passive acoustic (listening to sounds from the ocean versus sound sent out into the water as sonar or other active acoustic methods) techniques, autonomous technology, and other means.
Ocean Acoustics Program
NOAA’s Ocean Acoustics Program supports and conducts research examining the potential impacts of human sound on marine animals. The primary aims are to increase understanding of:
- Marine animals’ use of sound
- How underwater acoustics can be used to assess marine animal populations
- The degree to which anthropogenic activities are changing the underwater soundscape
- How these changes may potentially impact marine animals in their acoustic habitat
- What measures can be taken to mitigate these potential impacts
In order to increase our understanding of these issues, the program:
- Funds research directly through an annual NOAA-wide request for proposals
- Leverages funds with other government agencies to conduct work addressing impacts of noise on marine animals, as well as improve use of passive acoustic techniques to gather baseline life history and population data
- Conducts primary research utilizing passive acoustics in the regions including in the Arctic Ocean
- Provides technical support and advice on the management and assessment of protected species and anthropogenic impacts
- Coordinates on intra- and inter-governmental bodies and panels to address and highlight underwater noise issues
NOAA’s Ocean Noise Strategy
A NOAA team from multiple regions and offices has worked together to develop an Ocean Noise Strategy to guide the agency towards more effective and comprehensive understanding and management of ocean noise impacts on marine life in the years 2016 to 2026. NOAA’s Ocean Noise Strategy describes the agency’s vision for addressing ocean noise impacts to the species, ecosystems, and places it is entrusted to protect and guides agency actions towards that vision through a focus on the following goals:
- Science: Working with partners to fill critical knowledge gaps and build understanding of noise impacts over ecologically-relevant scales
- Management: Integrating actions across the agency to minimize the acute, chronic, and cumulative effects of noise on marine species and their habitats.
- Decision Support Tools: Developing publicly available tools for assessment, planning and mitigation of noise-making activities over ecologically-relevant scales.
- Outreach: Educating the public on noise impacts, engaging with stakeholders and coordinating with related efforts internationally.
The NOAA Ocean Noise Strategy Roadmap (PDF, 144 pages) articulates the goals of the Strategy and suggests approaches for achieving a more integrated and comprehensive understanding and management of ocean noise impacts on protected species and acoustic habitats.
Regional Ocean Noise Activities and Programs
The Cetacean Assessment and Ecology Program at the Alaska Fisheries Science Center uses passive acoustic techniques to monitor Alaskan waters for marine mammals and the natural and human-made noise in the environment. These data help establish baseline information critical for making decisions about Alaska’s marine resources.
The Northwest Fisheries Science Center’s Fisheries Engineering and Acoustic Technologies Team uses acoustics to count fish and track salmon.
The Southwest Acoustics Ecology Lab studies the ocean soundscape throughout the California Current, including biological (marine mammal) and anthropogenic (manmade) sounds. These data are used to better understand marine mammal populations and to inform how different anthropogenic noise sources, including offshore renewable development, might impact protected species.
The Northeast Passive Acoustic Research Group is interested in understanding the sounds animals, including fish and invertebrates, make using space- and time-based measures. We evaluate the impacts of human-produced sounds on acoustically sensitive marine mammals to inform management, conservation, and education.
The Southeast Fisheries Science Center's Passive Acoustic Monitoring Program uses passive acoustic methods to monitor natural and anthropogenic (human-made) sounds in the Gulf of Mexico and southeastern U.S. waters of the North Atlantic. We use acoustic data to understand seasonal, annual, and decadal trends in marine mammal distribution and density to understand abundance, movement patterns, and habitat use, as needed for management, restoration, and conservation.
The Center has an associated project to reduce impacts of anthropogenic noise on marine mammals as part of Deepwater Horizon restoration activities.
At the Pacific Islands Fisheries Science Center, the Cetacean Research Program uses a variety of passive acoustic methods to assess the health and status of cetacean populations in the Pacific Islands Region.
Other Acoustics Activities
- Ocean Acoustics Program Research Projects
- Technical Guidance for Assessing Effects of Anthropogenic Sound on Marine Mammal Hearing
- International Workshop on Soundscape Mapping (Predicting Sound Fields—Global Soundscape Modelling to Inform Management of Cetaceans and Anthropogenic Noise)
- NOAA CetSound Project: Cetacean and Sound-Field Mapping Working Groups
- Bioacoustics Lesson Plan For Teachers—a collaboration between the NOAA Northeast Fisheries Science Center and Woods Hole Sea Grant
- Passive Acoustic Monitoring in California’s National Marine Sanctuaries (National Marine Sanctuaries Webinar Series)
- Listening and Learning in Cordell Bank National Marine Sanctuary by Foster Scholar Samara Haver
- NOAA Pacific Marine Environmental Library Acoustics Program Sound Samples