The Bush Administration has given the Navy permission to use a low-frequency sonar that wreaks havoc on marine mammals.

Environmentalists' fears are partly based on the Navy's deployment of a powerful mid-range sonar in March 2000 during a submarine detection exercise in the deep water canyons of the Bahamas.

At least 16 whales and two dolphins beached themselves on the islands of Abaco, Grand Bahama and North Eleuthera within hours. Eight whales died. Scientists found hemorrhaging around the brain and ear bones, injuries consistent with exposure to loud sounds.

Twelve Cuvier beaked whales beached themselves in Greece during NATO ( news - web sites) exercises in 1996 using the low-frequency sonar, but the whales decomposed before scientists could investigate.