The U.S. Navy is barred from using high power sonar in training exercises due to the harm it causes to marine mammals, ruled a federal judge on Monday.  U.S. District Judge Florence-Marie Cooper pronounced the temporary injunction in response to a Navy demand to dismiss a lawsuit initiated by the Natural Resources Defense Council (NRDC).

The group claims that Navy had 14 training exercises to take place in the waters off Southern California, an area rich in marine life, using the harmful mid-frequency sonar.  NRDC states that this technology, by flooding large areas of the ocean with loud burst of sounds, causes injures or even whales’ strandings. 

The court decision was based on the stated argument that “mass strandings of whales following naval exercises have been documented” from the Bahamas and the Canary Islands to Greece and Taiwan; the whales’ beaching on land were following use of military sonar.

"(The ruling) confirms that, during sonar testing and training, the navy can and must protect whales and other marine life in the extraordinarily rich waters off our Southern California coast," NRDC lawyer Joel Reynolds said quoted by AP.

The U.S. Navy’s argument for the necessity of such use is that the proliferation of silent diesel-electric   submarines from many countries, including North Korea and Iran, puts in jeopardy the national security. We are disappointed in the court's decision and plan to appeal the imposition of an injunction," said Mr. Don Schregardus, deputy assistant secretary of the Navy for the environment. "The decision puts Sailors and Marines at risk by ordering the Navy to stop critical anti-submarine warfare training while we complete Environmental Impact Statements on our training ranges."

The Navy added that it has already taken into consideration curbing the effects the sonar might have on the marine mammals and that, during the 3 training exercises that had already taken place, no strandings or behavioral disturbance were reported.