Feds evaluating Navy's Guam sonar training plan

— Federal regulators are evaluating rules allowing the Navy to practice using sonar in waters around Guam and nearby Pacific islands so long as sailors take steps to protect whales and other marine mammals.

The National Marine Fisheries Service has already approved similar plans for sonar training in waters off Hawaii, Southern California and the Atlantic Coast. Approval for the Pacific Northwest is pending.

Sailors have been practicing with sonar in these areas for decades. But it recently began seeking permits for the training to comply with federal environmental laws.

The fisheries service said it doesn't expect the Navy's drills to result in serious injury or death of the marine mammals. But it noted that whale strandings have been associated with sonar exposure in the past.

Sailors training around the Mariana islands would have to adopt similar protective measures as those exercising with sonar in other areas.

These include assigning Navy observers to watch for marine mammals and shutting down sonar if the animals are spotted too close to ships.

Sailors would also have to make sure they don't set off explosions when animals are found nearby.

"We have to make sure there's a negligible impact to the affected species and stocks of marine mammals," to authorize the training, said Jolie Harrison, a fisheries biologist in the office of protected resources at the fisheries service.

The U.S. territory of Guam and the Commonwealth of the Northern Mariana Islands is the second to last area to be evaluated. The final region is the Gulf of Alaska.

The fisheries service says it is seeking comments from the public on its rule proposal through Nov. 19.

Harrison said her agency would regularly evaluate the latest scientific research on how marine mammals react to sonar to make sure the mitigation measures it's requiring of the Navy are up-to-date. "The field of marine mammal science is always moving forward and we need to keep that in mind," Harrison said. "We definitely have a mechanism in where we can adapt to the evolving science."

The Navy uses sonar to track enemy submarines. Sonar operators send pulses of sound through the ocean and then listen for objects, such as submarines, that the sound strikes.

Scientists say the sound may disrupt the feeding patterns of marine mammals. The sound may also startle some species of whales, causing them to surface rapidly.

The Navy has been using mid-frequency active sonar for some 40 years, but its military importance has been growing even as concerns about the environmental effects of sonar have increased.

The Navy is particularly worried about being able to track a growing fleet of quiet diesel-electric submarines – owned by China, Iran and North Korea among other countries – that are difficult to spot and follow underwater.

Guam and the Northern Mariana Islands are in the Western Pacific about 1,500 miles south of Tokyo and 3,700 miles west of Hawaii.