SAN FRANCISCO – The U.S. Navy agreed in a settlement approved Tuesday to limit where it operates certain sonar systems criticized by environmentalists as a threat to whales and other marine mammals.

The settlement approved Tuesday by a federal judge in San Francisco restricts the Navy's use of low-frequency sonar to specific military training areas near Hawaii and in the western Pacific Ocean.

“Today's agreement maintains the Navy's ability to test and train while shielding whales and other vulnerable species from harmful underwater noise,” said Michael Jasny, a policy analyst with the Natural Resources Defense Council, the lead plaintiff in the case.

In February, U.S. Magistrate Elizabeth Laporte found that low-frequency sonar blasted beneath the ocean's surface to detect submarines threatens the animals' ability to find food and avoid predators.

A lawsuit filed by conservation groups last year argued that regulators violated multiple federal environmental laws by issuing a permit allowing the Navy to use the sonar systems around the world.

Environmentalists argued that the extremely loud, low-pitch sounds used to detect submarines at great distances disrupted the behavior of whales hundreds of miles away.

In a separate case, the Navy is asking the U.S. Supreme Court to reconsider a federal appeals court ruling limiting the use of mid-frequency sonar in training exercises off Southern California's coast.

The Navy argues that the decision by the 9th U.S. Circuit Court of Appeals in San Francisco threatens the readiness of sailors and Marines while providing limited environmental benefit.