Inconclusive sonar report fans debate

By Ian Ith
Seattle Times staff reporter

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Even with expensive, high-tech tests, scientists found no evidence to prove that a Navy destroyer's sonar echoes near San Juan Island contributed to the deaths of several Puget Sound porpoises last spring, according to an eagerly awaited report released yesterday.

But the scientists wouldn't rule it out, either.

The inconclusive quality of the National Marine Fisheries Service report served to inflame the longstanding and bitter debate between the Navy and Puget Sound environmentalists over sonar testing in the Sound.

The Navy yesterday took the offensive, declaring the study clears the destroyer USS Shoup in the deaths of the harbor porpoises. And the admiral in charge of the Navy's Northwest operations affirmed the Shoup would continue to occasionally test its sonar in Haro Strait, under certain conditions.

That prompted environmentalists to complain the Navy was wrongly assuming its sonar posed no threat to marine mammals. And they again urged the Navy to halt all sonar testing here.

"If this proves anything, it's that the Navy isn't going to give up anything," said Ken Balcomb, who heads the Center for Whale Research on San Juan Island. He turned over one of the dead porpoises for the study, but the cause of its death couldn't be determined.

"And this will happen again." Balcomb said. "There's no doubt, especially if the attitude is that, 'We're exonerated and we'll practice sonar anytime we damn well please, anywhere we damn well please.' "

The 60-page report summarizes lab tests done on 11 porpoises collected in Puget Sound in May and June, around the time the Everett-based Shoup passed through Haro Strait on May 5, emitting midfrequency sonar signals. Witnesses said they saw orcas that appeared to huddle and then move in confusion, dangerously close to shore. A minke whale was seen jumping above the waves as it fled the area, an unusual behavior for that type of mammal.

Activists had hoped that testing would show evidence of damage to the porpoises' inner ears, indicating that sonar destroyed their echolocation senses and forced them to beach themselves or run into boats, or made them fatally sick.

Testing was done by a team of 14 scientists from around the country, who put many of the best-preserved porpoises through high-tech medical scanners and then performed traditional necropsies on all 11 in late July.
 
"Quite frankly, the team was pretty balanced," said Brent Norberg, the marine-mammal coordinator for NMFS' Northwest Region. "It's fair to say we weren't specifically trying to link the deaths of the animals to a specific incident. It wasn't a witch hunt."

The study found no conclusive proof of "acoustic trauma," or inner-ear damage, in any of the porpoises.

"There's no smoking gun," acknowledged Brian Gorman, a NMFS spokesman.

Instead, the study has found that two of the mammals died of "blunt force trauma," meaning from blows that could have been caused by beaching or being hit by a boat. Three died of natural disease.

The cause of death couldn't be determined for the other six because the carcasses were too decomposed or there simply was not enough evidence found, Norberg said.

But despite the lack of proof of acoustic trauma, the report also acknowledged that such damage is often hard or impossible to find, especially in decomposed samples.

"The possibility of acoustic trauma as a contributory factor in the mortality of any of the porpoises could not be ruled out," the report concluded.

And environmentalists latched tightly onto that sentence yesterday in urging the Navy to step back from sonar testing.

"I would like to see the Navy take a precautionary approach," said Fred Felleman of the group Orca Conservancy. "There's not a smoking gun, per se, but because of the potential that there is, we should redouble our commitment to make sure this doesn't happen again."

But Rear Adm. Len Hering, commander of the Navy Region Northwest, said he and his scientists see it differently.

"We don't look at it as vindication," Hering said. "But we believe it provides credibility for what we've been saying from the very beginning — that scientific evidence would show that sonar did not kill or cause the deaths of those marine mammals."

The Navy also pointed out that some of the dead porpoises studied by NMFS appear to have died before May 5.

Yet Hering was adamant that the Navy is not trying to ignore the possibility that sonar could affect marine mammals. He said the Navy spends several million dollars a year researching the subject. Still, he downplayed the effect of the sonar on the orcas in Haro Strait, saying the Navy doesn't believe that the orcas were anything more than "annoyed" by the high-pitched sonar signals.

The Shoup is the only vessel in the Puget Sound fleet equipped with midfrequency sonar, which has been blamed for causing whale strandings in the Caribbean and other areas, Hering said. The Shoup has not used its sonar in Haro Strait since May, and Hering vowed the Navy would be more careful about making sure no marine mammals were nearby when it did resume sonar testing.

"It is the Navy's intention to minimize the impact with any marine mammals in accordance of the law." Ian Ith: 206-464-2109 or iith@seattletimes.com

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