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Federal ocean scientists said yesterday they were unable to determine
whether Navy sonar caused a mass stranding of whales on the North
Carolina shore last year. In their report on the stranding -- one of
the largest and most troubling in two decades -- the National Marine
Fisheries Service researchers concluded that Navy ships had used sonar
in the area the day before the whales came onshore. But detailed
necropsies and analyses did not find any physical signs of a
connection between the loud sonar pings and the whales' rush to shore.
"Experts from around the country worked on these samples and tests,
and the bottom line is that we are not able to reach a definitive
cause for the stranding," said Aleta Hohn, the Fisheries Service's
lead scientist on the report.
The report concluded that most of the animals were otherwise
healthy.
In all, 33 pilot whales, two pygmy sperm whales and a minke whale
stranded and died within two days. Strandings of more than one species
at a time are rare.
The report on the January 2005 stranding had been anxiously awaited
by the Navy and environmentalists because the animals died near the
proposed site of a 660-square-mile underwater sonar testing range.
The Navy has said the sonar range is essential to train sailors and
will not be a danger to the many whales in the area. Some
environmentalists disagree, saying that the growing number of
strandings around the world linked to naval active sonar make the
range -- which is near a major whale migration path -- a threat to
animals.
The two sides, which are battling in court over sonar, interpreted
the report differently. "The NOAA report clearly acknowledges that
there is no pathology implicating sonar as a cause of the stranding,"
said James A. Symonds, director of the Navy's environmental
programs.
"We believe the time frame and the distance at which active sonar
was used, two to three days prior to the stranding and over 50
nautical miles from [the site of the stranding] make it extremely
unlikely that our sonar affected the animals in any way," he said.
Michael Jasny of the Natural Resources Defense Council disagreed.
"Today's report by the federal government establishes that sonar
was a possible cause of the January 2005 mass stranding," he said. "It
confirms that the event itself was highly unusual, being the only mass
stranding of offshore species ever to have been reported in the
region; and that it shared 'a number of features' with other
sonar-related mass stranding events."
Navies worldwide have been using powerful mid-frequency sonar for
years, but the link to whale strandings is quite recent. The U.S.
Navy acknowledged that its sonar caused a mass stranding in the
Bahamas in 2001, and numerous other suspected cases have been
reported. Most recently, Spanish officials concluded that beaked
whales that came ashore along the Costa del Sol most likely did so
because of naval sonar.
Fisheries Service acoustics specialist Brandon Southall said the
amount of sonar used in the area prior to the North Carolina stranding
was not unusual. But he said it was impossible to say whether the
sonar led to the strandings.
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