The U.S. Navy is seeking permits to expand sonar and other training exercises off the Pacific Coast, a proposal raising concerns from animal advocates who say that more sonar-emitting buoys would harm whales.

The Navy now wants to deploy up to 720 sonobuoys about 12 miles off the coasts of Washington, Oregon and Northern California.

The Navy's John Mosher says the increase sounds dramatic but the impacts aren't. He says anti-submarine warfare training is critical.

The waters in the training range are home to endangered whales such as orcas, humpback and blue, as well as seals, sea lions and dolphins.

Critics say the noise from sonar can harass and kill whales and other marine life. They worry the Navy is expanding training exercises without increasing efforts to reduce the impacts.