Ocean Voices

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Importance of sound in the ocean

Sound is critical for survival for many animals in the ocean. Sound can be used for communication, foraging (finding food), navigation, and avoiding predators. Many of the sounds made by humans, animals and other natural sources (wind, waves, earthquakes) can be recognized based on unique characteristics.

A soundscape consists of the collection of all sounds present. Different habitats contain different sounds, and have different soundscapes. Scientists track patterns in soundscapes and how animals use different habitats to monitor protected species, and evaluate the impact of human activities on the environment. It’s important to understand what animals and human activities are present so that we can understand if changing noise levels are from natural or human sources.

How to protect whales by studying sound

Two of the biggest threats to large whales today include ship strikes and entanglements. We can study underwater sound to understand when and where the whales are found, and then we share that information with managers who decide how to plan shipping and fishing activities.

Ocean noise can also potentially interfere with important behaviors and have impacts on the survival of individuals and health of populations.

Potential impacts of ocean noise include:

• Relocation: Animals may leave important habitat to avoid noise
• Disruption of important behavior: Animals may adjust feeding, mating, rest and communication
• Hearing loss: Noise can cause both temporary and permanent hearing loss

We need your help

By helping to analyze acoustic data, you’re helping to discover where the whales are and how they are using different habitats so that we can better coexist with our oceanic neighbors.

Acoustic ecology can be a big-data challenge. We are collecting more data than human scientists can analyze in their lifetime, so we are recruiting citizen scientists to help train machine learning algorithms to automatically detect the sounds we are studying.

Data Collection

Hydrophones are suspended 100 m (~330 ft) below the surface on buoys that drift with ocean currents for days or weeks at a time. The sounds are saved on a SoundTrap recorder, but we have to recover the buoy to analyze the data. This method of recording ocean soundscapes (passive acoustic monitoring) is a great way to study the animals in a non-invasive way. Passive acoustic monitoring is also useful to study habitats that are remote or otherwise impossible to access - like the deep ocean!

Maps of drifting buoys deployed during NOAA surveys

More details about ADRIFT data collection can be found on the NOAA Southwest Acoustic Ecology ADRIFT website and in these reports:

• Rankin, S., Burger, K., Hom-Weaver, C., Palmer, K., Sakai, T., Simonis, A. 2024. Final Report for Adrift in the California Current Survey: Passive Acoustic Monitoring in the California Current using Drifting Recorders. Camarillo (CA): U.S. Department of the Interior, Bureau of Ocean Energy Management. 111 p. Report No.: OCS Study BOEM 2024-047. Contract No.: G14 M20PG00013.
• Simonis et al., (2018). "Passive Acoustic Survey of Deep Diving Odonotocetes in the California Current"

ADRIFT

ADRIFT is a research project studying marine mammals and ecosystems by listening to sounds throughout the California Current Ecosystem! The ADRIFT research took place between 2020-2023 and was led by Shannon Rankin at the NOAA Southwest Fisheries Science Center.

CalCurCEAS is an acronym for the California Current Cetacean and Ecosystem Assessment Survey. The CalCurCEAS survey occurs about once every 4 years, and it is led by Dr. Jeff Moore at the NOAA Southwest Fisheries Science Center.

Funding

This study was funded in part by the U.S. Department of the Interior, Bureau of Ocean Energy Management through Interagency Agreement M20PG00013 with the U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service (NMFS), Southwest Fisheries Science Center (SWFSC).