The US Navy is facing legal action from environmentalists over its use of sonar in routine training, according to reports. The Natural Defense Resources Council (NRDC) argues in a federal lawsuit that the sonar can cause injury and death to many marine mammals, and that the Navy is violating environmental law with its sonar use.

The NRDC says that mid-frequency sonar is behind mass strandings of whales and dolphins, and can cause internal bleeding in these mammals, Reuters reports. It also accuses the Navy of failing to take proper precautions to prevent injuring these animals.

The Navy, while not commenting specifically on the lawsuit, says its sonar use is critical to national defence, and is a vital part of its training programme. It added that it employs "scientifically-based protective measures" as part of a "comprehensive strategy for assessing the potential effects of its use of mid-range active sonar on marine mammals".

But the coalition of environmental groups would like the Navy to be more judicious in its use of the technology. In the suit, it asks the court to force the Navy to avoid migration routes, and to gradually increase the volume of sonar, which it says would give animals in the area time to swim away.

"Military sonar needlessly threatens whole populations of whales and other marine animals," NRDC lawyer Joel Reynolds told Reuters. "In violation of our environmental laws, the Navy refuses to take basic precautions that could spare these majestic creatures. Now we're asking the courts to enforce those laws." ®