But the environmental impact statement on the system, to be published Friday, already is drawing criticism from some conservationists and scientists. We hope they'll be receptive to criticism, because there will be a lot of it. Traditional sonar detected enemy submarines by simply listening to the sounds they made. But as submarines grew quieter, making detection ranges shorter, the Navy began developing a system a decade ago that sends out loud pulses of sound from 18 bathtub-sized speakers strung along an underwater array. Technicians then listen for the sounds to return, said Joe Johnson, program manager.
Sound waves bouncing off submarines sound different from waves ricocheting off rocks or animals.
The prevailing theory in scientific literature was that animals will not stay around 140 decibels, so we went out to show that. But we weren't very successful. But given the fundamental importance of sound to creatures in the sea, not just whales, fish as well, it's premature to draw sweeping conclusions from the limited research accomplished thus far. The Navy plans to hold public meetings around the country on the impact report starting Aug. 4 in Washington. Copyright 1999 The Associated Press.