Earth's Journal

Biosphere Journal Entry

Court Decision Protects Whales (September 12, 2003)

beaked whale

Last year, two beaked whales were killed by government sonar tests. Photo courtesy U.S. Mineral Management Service (MMS).

A federal court shot down a United States Navy plan for widespread use a new sonar system, saying it may harm whales and other marine mammals. Research done at Woods Hole Oceanographic Institute in Massachusetts showed that the low-frequency sound waves used by the sonar would interfere with whales' ability to communicate with each other. It may also affect their feeding and migration.

The Navy's sonar system uses a series of car-sized speakers to send out sound waves at between 250 and 500 hertz. The intense sounds can be picked up by sensitive marine mammals hundreds of miles away. The federal judge ruled the Navy could not use the system in important marine mammal habitat covering about 40% of the Pacific Ocean. But the sonar will be allowed in some areas populated with less marine life.

Marine biologists say past sonar tests caused whale beachings and deaths. Whales beached in areas where these tests were conducted in the Bahamas, Canary Islands, and the Gulf of California between Baja California and mainland Mexico. Some were found with bleeding inside their ears, likely from damage from the powerful sound waves.