for National Geographic News
The U.S. Navy was forced to stop using high-intensity sonar during training exercises off Hawaii yesterday after an environmental group won a temporary restraining order.
The exercises would have involved generating underwater mid-frequency sound waves to search for "enemy" submarines.
But environmentalists are concerned that the sound waves have a harmful effect on marine mammals, such as whales and dolphins, that swim in Hawaiian waters (map of Hawaii).
This year about 19,000 service men and women from eight countries are participating in the Navy's Rim of the Pacific exercise, the world's largest international maritime training event.
For now the group has been training with passive sonarusing microphones to track noises made by underwater objectsand visual searches, says Vice Adm. Barry Costello, commander of the U.S. Third Fleet.
But the Navy has asked for an appeal on the restraining order, citing a need for more realistic training practices.
"Preventing ships, helicopters, airplanes, and submarines from actively hunting submarines with mid-frequency active sonar seriously compromises the realism of the exercise and degrades the sailors' training," Costello said in a written statement.
The temporary restraining order was issued Monday, just days after the U.S. Department of Defense granted the Navy a six-month exemption from federal laws protecting marine mammals.
Mid-frequency sonar has been linked to mass strandings and deaths of whales, dolphins, and other marine species around the world, says the Natural Resource Defense Council (NRDC), which filed the lawsuit.
This is the third time the NRDC has sued the Navy over sonar safety concerns, says organization spokesperson Hamlet Paoletti.
Marine biologists believe strandings can be caused by many factors, including parasites, pollution, trauma, and starvation.
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