All About Ocean Noise

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