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You can't talk on a cell phone when you're on an airplane. Your phone and the pilot's navigation system use the same frequency, and the signals could interfere with each other. The U.S. military and whales off the Pacific coast are having a similar conflict, and it's not clear who will come out on top.

Since the late 1990s, the U.S. military has been experimenting with the use of sonar to detect super-quiet submarines. The U.S. Navy says this technology could be helpful in detecting submarines and underwater threats from other nations. But the new sonar, called low-frequency active (LFA) sonar, employs the same frequency whales use to navigate and communicate with each other. A study commissioned by the U.S. Navy concluded that the whales were affected while the sonar was in use, but that their patterns returned to normal after the sonar was turned off. Environmentalists and whale watchers say the study doesn't answer questions of whether the whales suffer hearing loss or other permanent damage from the sound waves, which are very loud and can be carried through the water for hundreds of miles.

The conflict highlights two related dilemmas that have become more prominent in the wake of September 11th: Balancing environmental concerns with a desire to protect national security, and controlling underwater noise pollution, caused by warships, cruise liners, and exploration, that can disrupt communication and navigation systems of whales and dolphins.

| REPORTS |

The story:

American officials will soon decide whether to use LFA sonar. The U.S. Navy says the whales are safe, but activists worry about long-term effects.
(4/22/2002)
Hear it

Webcasts May 4 and 18
Why do things sound different under water? How to bats navigate? Check out our spring webcasts as the kids from the Aim High program make echos, investigate the workings of their ears, and visit with a real live bat!

How does sonar work?
See how reflected sound waves help a whale find its food -- or an officer find a submarine.

What does the Navy's sonar sound like?
A biologist at Cornell University has been studying whale songs and asking whether the Navy's sonar affects them. You can listen to the whales and to their calls amidst the LFA sonar blips.

Sound is louder under water. Try this!
This simple experiment you can do at home will show you that water is a very effective carrier of sound.

How do animals navigate?
Sonar is one of several tricks animals use to find their way around the world. Aside from eyes and ears, some species -- including whales -- use small magnets in their bodies!

Navy's environmental impact statement
Documents from 1999 and before describe how LFA sonar will be used, how it relates to whale sonar, research on how LFA might affect people diving in the area, and other information.

One rebuttal
Environmental groups, like the National Resources Defense Council, say FLA sonar has a lasting and detrimental effect on whales.

The latest
The issue of sonar and whales is sure to stay in the headlines. Check our links page for headlines and background news articles.


© Exploratorium 2001