Stay connected with us
around the nation »

Blinded by the Noise—Whales and Dolphins in a Noisy Ocean

Many marine mammals use hearing to find their way through the world. But parts of the ocean are filling up with man-made noise, and that has the potential to leave them partially blinded. The CETSOUND project might help.

By Rich Press, NOAA Fisheries Science Writer | Posted: September 3, 2013
Follow Rich on Twitter: @Rich_NOAAFish


RSS Feed  iTunes


Aerial photo of a gray whale and dolphins. View slideshow A group of long-beaked common dolphins surf the bow wave of a migrating gray whale. Whales and dolphins use sound to communicate, to orient themselves, and to navigate through their environment. Increasing man-made noise from shipping and other industrial activities has the potential to interfere with their activities. Credit: NOAA. img01_deployment.jpg img02_maru1.jpg img03_maru2.jpg img04_listening.jpg img06_sonobuoy.jpg img07_ontheice.jpg img08_map1.jpg img09_map2.jpg img10_sbnms_ani.gif img11_freq_relationships.jpg

The ocean is mostly dark, but it's full of sound. That's because sound waves travel very far in the ocean, whereas light can only penetrate a few hundred feet. Over millions of years, whales and dolphins have evolved into exquisitely tuned instruments for both emitting and receiving sound.

Cetaceans—that is, whales and dolphins—use sound to find prey and avoid predators, to maintain family and pod structures, and to find mates. And though it is difficult for visual creatures like us to imagine, they use their sense of hearing to orient themselves in space and to navigate through their environment.

Related Links

To learn more, visit NOAA's CETSOUND project website.

Download maps from the CETSOUND website. (Select a region, then click the “i” icon. Next, click the image gallery link that appears under the title.)

Check out Sounds in the Ocean, a NOAA website that allows users to listen to and download sounds made by many types of marine mammals, and anthropogenic sounds as well.

Also visit the Discovery of Sound in the Sea website to learn more about the science and uses of sound in our oceans. Exit

Meet Mike Bahtiarian, a noise control engineer who contributed to this podcast. Exit

Unfortunately for them, parts of the ocean are filling up with man-made noise. Military sonar, oil and gas exploration, and underwater construction all send powerful, intermittent pulses of sound into the ocean. And shipping, which is increasing in line with global trade, creates a continuous background rumble. This growing cacophony has gotten to the point where it has the potential to impact the health of many marine mammal populations.

Our uses of the ocean will only continue to grow, and it will not be possible to remove anthropogenic noise from the ocean. But we may be able to organize our activities so they don't happen in places and at times that are particularly sensitive for marine mammals.

As a first step toward this goal, a group of scientists from NOAA, Cornell University, and other organizations are working on a mapping project called CETSOUND. That’s short for cetaceans and sound, and the project has two components. The first is a series of maps showing where and when marine mammals occur in U.S. waters—their migration routes, nursing grounds, and so on. The second is a series of maps showing the estimated noise levels that those areas are exposed to throughout the year.

By overlaying these maps, scientists and decision-makers can see the hotspots for noise that affects marine mammals, and they can begin to manage the problem.

Unlike marine mammals, we humans are visual creatures. We can't really address a problem until we can visualize it. That's what these maps accomplish. They allow us to visualize something that until recently, we were mostly blind to. Now that we can see the sound, we can start to do something about it.

<< Podcast Home