Environmental organizations filed a lawsuit [on December 16] against the National Marine Fisheries Service to demand it force the Navy to consider alternatives to its five-year plan that will intensify its sonar use off Southern California and Hawaii. Earthjustice, representing several groups, filed the lawsuit ... only hours after the federal agency announced it had decided to grant the Navy permits to move ahead with its plans for training and testing in the Pacific. Environmentalists [favor] creating zones that would be off-limits to biologically sensitive areas [and] want the Navy to avoid training in certain spots seasonally when they are rich in marine life. "The science is clear: sonar and live-fire training in the ocean harms marine mammals," said Marsha Green of Ocean Mammal Institute. "There are safer ways to conduct Navy exercises that include time and place restrictions to avoid areas known to be vital for marine mammals' feeding, breeding and resting." Reported mass strandings of beaked whales have increased around the world since the military started using sonar more than half a century ago. The sounds can scare animals into shallow waters where they can become disoriented and wash ashore. Aside from beachings, biologists are concerned about prolonged stress from changes in diving, feeding and communication habits. Two recent studies off the Southern California coast found certain endangered blue whales and beaked whales stopped feeding and fled from recordings of noise similar to military sonar. Beaked whales are highly sensitive to sound and account for the majority of strandings near military exercises.