The Navy can use high-intensity sonar in some circumstances for Pacific warfare exercises under an agreement reached Friday with environmental groups, four days after a judge banned the sonar over concerns it could harm marine mammals.
The settlement prevents the Navy from using the sonar within 25 miles of the newly established Northwestern Hawaiian Islands Marine National Monument during its Rim of the Pacific 2006 exercises, and also imposes a variety of methods to watch for and report the presence of marine mammals.
The environmental groups, led by the Natural Resources Defense Council, had obtained a court order Monday temporarily barring the use of the “mid-frequency active sonar.”
Environmentalists claim whales have stranded themselves on beaches after being exposed to high-intensity mid-frequency sonar. In some cases, whales bled around the brain and in the ears. The sonar is also claimed to interfere with the ability of marine mammals to navigate, hunt, take care of their offspring and avoid predators.
The Navy had previously received a six-month exemption from federal laws protecting marine species in its use of the sonar, prompting the environmental group to seek the court order.
U.S. District Court Judge Florence-Marie Cooper wrote in that order that the plaintiffs had shown a possibility the Rim of the Pacific 2006 exercises “will kill, injure, and disturb many marine species, including marine mammals, in waters surrounding the Hawaiian Islands.”
‘Arbitrary and capricious’
The Navy’s failure to prepare an environmental impact statement or otherwise take a “hard look” at the environmental impact of war games was an “arbitrary and capricious” violation of federal law, Cooper wrote.
"Plaintiffs have submitted considerable convincing scientific evidence demonstrating that the Navy’s use of MFA sonar can kill, injure, and disturb many marine species, including marine mammals," Cooper said in her ruling.
The Pacific exercises began June 26. The sonar portion of the exercises is intended to train sailors to detect and hunt stealthy submarines.
The settlement agreement requires the Navy to use electronic airborne monitoring for marine mammals, and requires the Navy to put a marine mammal lookout on all surface ships operating the sonar.
First time permit granted
NOAA on Tuesday granted the Navy a permit to use the sonar. It was the first time such a permit had been granted to the Navy.
NOAA determined that the exercise would cause no significant environmental impact, and concluded that the Navy’s use of the sonar was not likely to jeopardize the continued existence of threatened and endangered species — including the Hawaiian monk seal — in the exercise areas.
As part of the permit agreement, the Navy said sonar operators will reduce active sonar power by 75 percent if a marine mammal is spotted within 1,094 yards of the ship, and drop it further if mammals are detected within 547 yards. They will turn off the sonar if the mammal is detected within 219 yards.