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US agrees to save whales by limiting sonar use
By Oliver Poole in Los Angeles
(Filed: 14/10/2003)


American whale-lovers claimed yesterday to have forced the US navy to abandon the peacetime use of a new submarine-detecting sonar system in virtually all the world's oceans.

The National Resources Defence Council argued that the sound of the sonar was deafeningly loud to marine mammals, startling them and making them ascend too quickly, giving them the "bends".

The NRDC, which sued the military over the use of the sonar, said it had struck a deal under which the navy promised to use the system only in specific areas along the eastern seaboard of Asia.

In November 2000, 16 whales and two dolphins beached themselves on islands in the Bahamas after the US navy used its existing, less powerful, sonar in the area. Eight whales died and hemorrhaging was found around their brains and ear bones.

In other cases studied by scientists from the Zoological Society of London and the University of Las Palmas bubbles were found in the bodies of beached cetaceans similar to those from decompression sickness in human divers.

A US magistrate had issued a preliminary injunction restricting the sonar's use and ordered the two sides to negotiate a final settlement. The agreement apparently largely mirrors the magistrate's original injunction.

The US Navy declined to comment yesterday.

Joel Reynolds, the director of the marine mammal protection project at the NRDC, said: "This agreement will prevent the needless injury, harassment and death of countless whales, porpoises and fish, and yet allow the navy to do what is necessary to defend our country."

In addition to limiting testing to areas near Asia, where deep water is believed to limit the extent of any damage, the navy agreed to seasonal restrictions to protect whale migrations.

None of the restrictions would apply in time of war.

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Submarine sonar 'gives startled whales and dolphins the bends'
By David Derbyshire
(Filed: 09/10/2003)


Deafening sonar booms are giving whales and dolphins fatal doses of the bends, according to research.

Scientists believe they may be startled by the sound from submarines and forced to ascend too quickly. Researchers have shown for the first time that deep diving marine animals can suffer from decompression sickness - a potentially deadly condition experienced by divers who resurface too quickly.

They are calling for more research into the dangers of sonar and tighter controls on its use.

Post mortem examinations on 14 whales stranded during a naval exercise in the Canaries last year revealed bubbles of gas in their blood and holes in their internal organs - symptoms of the condition. Tests on dolphins and whales stranded on Britain's coasts over the past decade have revealed similar damage.

A team at the Zoological Society of London and the University of Las Palmas, Gran Canaria, studied beaked whales and Risso's dolphins stranded on Britain's coasts between 1992 and 2003.

Dr Paul Jepson, from the society's UK Marine Stranding Project, who reported the findings in Nature, said: "We discovered that a small number of stranded animals had gas bubbles and associated tissue injuries.

"Although decompression sickness was previously unheard of in marine animals, we concluded that a form of marine animal decompression sickness was the most likely cause.

"This new evidence from our study of marine mammal diseases in the UK challenges the widely held notion that cetaceans (whales and dolphins) cannot suffer from decompression sickness."

The link with sonar emerged when 14 beaked whales were stranded in the Canary Islands four hours after a Spanish-led naval exercise in September 2002. Ships in the area were using mid frequency sonar. The exercise ended when the stranded whales were discovered.

Post mortem examinations of 10 whales revealed more evidence of the bends.


Further reading:

http://www.zsl.org/news/n_0000001283.asp
 

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New Scientist article mentions the same thing.

Although the symptoms are bend-like the cause is thought to be different.

"post-mortems also revealed clots of fat in blood in their brains, livers, lungs and kidneys and other tissues, along with widespread haemorrhaging.  In humans, these are all signs of decompression trauma."

The one theory is deep diving whales were startled by the incredibly strong sonar and surfaced too quickly.

The leading theory though backed up by some mathmatical modelling is that sonar may repeatedly compress and expand small gas bubbles causing them to dangerously enlarge.

Other evidence comes from London Zoo with 1401 dolphins and porpoises stranded around the UK between 1992 and 2003.  Seven were found to have gas bubbles in blood and liver.  (Nature v425, p575)

The new US Navy LFA sonar produces sound pressures of near 230db whereas current military sonars of nearer 120db have been found to have some biological effects.  Remembering how the decibel scale works, this is a HUGE increase.


"Bowhead whales show avoidance at 120 dB as do gray whales in the migratory path of sound at this level
Humpback whales exhibit cessation in "singing" above 155 dB
Sperm and pilot whales stop singing when exposed to 220 dB"

"According to the Navy's own study, scientists briefly exposed a 32-year-old Navy diver to LFA sonar at a level of 160 decibels -- a fraction of the intensity at which the LFA system is designed to operate. After 12 minutes, the diver experienced severe symptoms, including dizziness and drowsiness. After being hospitalized, he relapsed, suffering memory dysfunction and seizure. Two years later he was being treated with anti-depressant and anti-seizure medications."

"At the test source, 215dB are produced from a single array (up to 235 for multiple arrays) (2.1.1 and response to Comment 2-1.1 (Page 10-47) of the Navy FEIS). The sound field designed as the LFA mitigation zone is greater than or equal to 180dB within 22 km (12nm) of any coastline and in the offshore biologically important areas that exist outside the 22km zone during the biologically important season for that area. (2.3.2.1 Navy FEIS.)"

Also a mathmatical treatment on predicted LFA impact http://home1.gte.net/leetpley/resonance_p1_toc.html


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All in all, it seems there is some correlation between sonar use and whale/dolphins casualties and the LFA sonar being developed could make matters worse.
 
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