A federal judge in Honolulu yesterday said the Navy will have to use more sonar protections for whales and dolphins during a series of anti-submarine warfare exercises off Hawai'i — a ruling that could set a precedent for future training here.

The preliminary injunction issued by U.S. District Judge David Ezra is a third setback for the Navy after two recent rulings on the West Coast restricting the Navy's use of active sonar, which sends sound waves into the water.

The Hawai'i case stemmed from a May 2007 lawsuit seeking to stop the sonar exercises for carrier and amphibious strike groups heading to the western Pacific from the West Coast of the United States.

Ezra, noting that "this is an extremely complex issue on which there is still much uncertainty," said he balanced environmental law and the effects of sonar on mammals with the Navy's need to train.

One of the targets for quiet diesel electric submarines from potentially hostile nations such as China, North Korea or Iran is the U.S. aircraft carrier, and the inability to train using mid-frequency sonar would "put thousands of American lives at risk," Ezra said in the 84-page opinion.

But while the Navy disputes the factors associated with marine mammal strandings, "there is little disagreement that (mid-frequency active) sonar can cause injury, death and behavioral alteration to these animals," Ezra said.

He added that the "balance of hardships slightly favors the plaintiffs here."

Ezra's order notes that at least 26 species of marine mammals frequent Hawai'i's waters. The use of mid-frequency Navy sonar was determined to be a "plausible, if not likely" contributing factor to the mass stranding of up to 200 melon-headed whales in Hanalei Bay during Rimpac exercises in 2004.

In April 2007, the court order states, the Navy conducted two anti-submarine exercises in Hawai'i waters and shortly thereafter, two pygmy sperm whales washed up on Lana'i and Maui.

High-level acoustic exposures have been demonstrated to adversely affect marine mammals, resulting in injuries including ruptured hearing organs and behavioral modifications, according to Ezra's order.

The Navy has maintained it is a good steward of the environment and already takes adequate steps to avoid impacts on whales and dolphins while also conducting crucial sonar training.

'SAFETY ZONES' ORDERED

Among the requirements ordered by Ezra yesterday are "safety zones," including the need for the Navy to power down active sonar by six decibels when a marine mammal is spotted within 1,500 meters of a sonar-emitting vessel.

The sonar power must be stepped down the closer the animal is, and within 500 meters, all sonar transmission must cease.

U.S. Pacific Fleet said in a statement that the restrictions "could seriously impact our ability to train effectively."

"In ordering additional mitigation to reduce the risk to marine mammals, the order shifts the risk to sailors and Marines," the Pacific Fleet said. "We are carefully assessing the impacts that the injunction will have on our training and our legal options."

Paul Achitoff, an Earthjustice attorney representing the plaintiffs, said the measures ordered by Ezra are "useful," and will help reduce the impact on marine mammals.

"There are other things that we asked for that he hasn't ordered that we would certainly like to see in place," Achitoff said.

Achitoff said he'll be seeking a permanent injunction. The order issued by Ezra will "have influence on the way in which they (the Navy) do any exercises from now on in Hawai'i," he added.

"I think (Ezra) has made it clear that he considers it reasonable to expect the Navy to do at least these additional things, and he does not feel that doing these things will interfere with effective training," Achitoff said.

The Ocean Mammal Institute, Animal Welfare Institute, KAHEA, Center for Biological Diversity and Surfrider Foundation, which filed the lawsuit in 2007, wanted sonar shut down within 2,000 meters of marine animals.

The Navy had proposed to power down sonar transmission within 1,000 meters and turn it off within 200 meters. Ezra's order was a compromise, with a reduction at 1,500 meters.

MONITORING REQUIRED

Ezra's order also requires that each day mid-frequency active sonar is used, the Navy must monitor for the presence of marine animals for 60 minutes before sonar is employed.

The Navy must use three dedicated lookouts, and aircraft already being used for an exercise, or where practicable, to assist in monitoring.

Ezra also ordered that the Navy power down sonar when multiple factors are present, including rapid changes in water depth, when there are three or more sonar-emitting vessels, and if the sonar occurs in narrow channels.

Before initiating any exercise with sonar, the Navy will have to gradually "ramp up" sonar transmissions — something that the Navy said would harm its training, the court order states.

Ezra said the weight of evidence points to avoidance of marine mammal habitats as the most effective means of minimizing sonar-related injury, and as such, avoidance of near-shore areas is one generally accepted method.

The Navy previously "recognized the value" of adhering to sonar exclusion zones, including a 25-nautical-mile zone for Rim of the Pacific, or Rimpac, war games in 2006, Ezra noted.

Ezra said a 12 nautical mile limit "may be reasonable" for upcoming anti-submarine warfare exercises, but he decided to revisit the issue after the next exercise in March, which the Navy said would occur no closer than 40 nautical miles from shore.

The Navy previously said Hawai'i's waters provide unique deep- and shallow-water environments to conduct anti-submarine warfare training in a world environment in which 300 of 380 foreign submarines are quiet diesel electric models.

Reach William Cole at wcole@honoluluadvertiser.com.