SAN FRANCISCO — A federal appeals court yesterday said the U.S. Navy could use high-power sonar during exercises off the Southern California coast despite the technology's threat to whales and other marine mammals.

A majority on a three-judge panel of the 9th U.S. Circuit Court of Appeals said the Navy can use the high-power sonar in 11 planned training exercises in its reversal of a lower-court order banning the practice.

Judge Andrew Kleinfeld, writing for the majority, said national security interests outweigh the possible harm to marine life.

"The public does indeed have a very considerable interest in preserving our natural environment and especially relatively scarce whales," Kleinfeld wrote. "But it also has an interest in national defense. We are currently engaged in war, in two countries."

Judge Milan Smith Jr. disagreed with his colleagues on the panel and said he would have kept the ban in place.

Navy officials said they're pleased that the court approved their motion to stay a lower court ruling that would bar the Navy from using active sonar in certain multi-ship exercises off Southern California through January 2009.

"Today's ruling allows us to resume active sonar training for our carrier and expeditionary strike groups," Navy spokesman Capt. Scott Gureck said in a news release.

"These integrated sonar training exercises are absolutely essential for our strike groups to conduct before they deploy to the Western Pacific, the Middle East and around the world."

Gureck added, "The ability to detect and track potentially hostile submarines is a critical skill that cannot be duplicated in the classroom or by simulation."

More than 40 nations, including Iran and North Korea, deploy extremely quiet diesel-electric submarines. Active sonar is used to locate them, and anti-submarine warfare is the Pacific Fleet's top war-fighting priority, the release stated.

Adm. Robert Willard, commander of the U.S. Pacific Fleet, said in the release: "The initial injunction left us in an untenable position of having strike groups needing this training and not being able to accomplish it."