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Death knell

The latest in a series of mass strandings of whales around the world has implicated naval use of modern sonar equipment. Owen Dyer looks at how the military are trying to avoid responsibility

30th October 2002

The Guardian

Last month, 17 whales beached and died in the Canary Islands. Nobody knows for sure what killed them, but the government of the Canaries made an educated guess. Four mass whale strandings have occurred in the islands in the last 20 years, and each one of them coincided with NATO naval exercises.

This time was no exception. Neo Tapon 2002, a NATO exercise hosted by the Spanish government, had just left the area. NATO argues that there is no proof of a causal link. However, the local authorities politely have asked them not to return.

In the summer of 2000, 17 whales of various species beached in the Bahamas. Necropsies revealed bleeding in the ears and brains. Just an hour before the first whale was found, a squadron of American destroyers had passed close by.

In 1996, 12 Cuvier's beaked whales died among the Greek islands, immediately following NATO naval exercises. NATO was testing a new system of sonar that many marine biologists fear could prove the final straw for the harassed leviathans' low frequency active sonar.

Sonar, the acoustic system that ships use to find submarines, is the prime suspect in all these cetacean deaths. Everyone is familiar with the pinging sound that punctuates old submarine movies. This is active sonar, a sonic equivalent of radar. The submarine hunter emits pings that bounce off the hull of the lurking sub and are picked up by microphones.

Sonar has changed dramatically in the last few years. Cold war technology relied on passive sonar, which emits no sound but merely listens for the engine noises of the underwater enemy. Passive sonar is no longer good enough, according to military planners, as modern subs are just too quiet. So navies are turning back to active systems, but these new sonars emit pings that are millions of times louder than the vintage models.

The US navy's new sonar, called Surtass LFA, carries 18 loudspeakers that generate 235 decibels each. In crude terms, that is equivalent to standing next to an Apollo moonrocket. At a range of 160 kilometres, the signal can still reach 160 decibels. That is 50 times louder than the US navy's official safety limit for human divers.

When it emerged in 1996 that the US navy had conducted at least 22 secret tests of Surtass LFA around the US coastline, marine biologists and environmental groups were enraged. The National Resources Defense Council, one of America's biggest environmental groups, accused the navy of breaching the Endangered Species Act, the Marine Mammal Protection Act, and the Environmental Policy Act, which demands that an environmental impact analysis be performed before undertaking any potentially harmful activity.

Hoping to avoid a lawsuit, the navy promised to perform environmental studies. These consisted of observing the reactions of humpback, right, grey and fin whales to reduced-power signals from the LFA array. The tests produced clear reactions from most whales exposed to the sonar, with the majority fleeing the scene.

At the end of it all, the US navy announced that the observed reactions did not add up to a "significant biological impact" that might interfere with mating, feeding or migration. That, say conservation groups, is a completely arbitrary judgment.

What worries scientists most is that none of those whales were exposed to much more than 150 decibels, yet the navy used those results to set a safety limit of 180 decibels, a level 1,000 times louder.

The US navy is under fire precisely because it is more open and accountable than European navies, whose LFA programmes are developing away from public scrutiny. Anthony Watts, the editor of Jane's Underwater Warfare, says France, Germany and Britain are all building similar systems. "The French system is about 220 decibels; the German model, intended for export, is about the same. The British system's power is classified."

The Ministry of Defence says revealing the sound level would allow enemies to calculate the performance. They acknowledge, however, that they are buying 21 LFA sonars to equip type 23 frigates. That compares to just four LFA-equipped ships in the US programme.

British tests took place this summer in the Bay of Biscay, while American active sonars were being tested off the Kyle of Lochalsh in Scotland. Britain's Whale and Dolphin Conservation Society worries that this might explain why sperm whales are now avoiding that ancient western migration route and ending up in the North Sea.

Doug Spencer of the US Office of Naval Research says operators are careful to mitigate the impact on marine life. "The system will be turned off if a whale strays within the 180 decibel zone. It will also be turned up slowly, so as to give cetaceans a chance to escape.” But evidence from the Bahamas and the Canaries suggests they may have to swim very fast and very far to be safe.

During the Bahamas strandings, one of the dead whales washed up by chance in the backyard of cetacean specialist Ken Balcomb, of the Centre for Whale Research. His findings pushed the US navy into investigating the event. Their preliminary report admits that "tactical mid-range frequency sonars aboard US navy ships were the most plausible source of this acoustic or impact trauma".

One of the whales, he says, was at least 15 miles from the ships when it suffered a brain haemorrhage. "This was from a sonar far less powerful than the LFA. I'd estimate they received about 165 decibels", he says. The US navy has not mentioned these long-term effects in its environmental studies, nor has anyone ever conducted environmental assessments of the tactical active sonars that are standard equipment on warships around the world.

Balcomb says the damage is permanent. None of the whales that were in the area at the time have been seen since. "I'd say they're all dead and on the bottom. Only a small minority of those killed would wash up on shore. It makes you wonder how many are dying in deep water with nobody knowing. Sea turtles and fish with swim bladders are also probably susceptible.” Other studies have shown that active sonar cuts growth rates and reproduction among shrimp, a cornerstone of the marine food chain.

Having admitted that sonars kill whales, the US navy could no longer legally test LFA without breaching the Marine Mammal Protection Act. The answer was to seek, and get, a "small take" permit from the National Marine Fisheries Service, which allows them to legally kill or harass small numbers of marine mammals.

Even more controversially, the US navy argued that the Environmental Policy Act does not apply outside the 12-mile coastal zone. This would free them from any obligation to perform environmental impact assessments. This was too much for US environmental groups, and now the navy faces the lawsuit they tried so hard to avoid.

This week, the National Resources Defense Council and an assortment of other parties including the Humane Society and Jean-Michel Cousteau will sue the navy and the fisheries service in the California District Court. They will argue that a small take permit is totally inappropriate for a system that is planned to cover 75% of the world's oceans. Joel Reynolds, attorney for the NRDC, believes he has strong legal arguments and a real chance of winning.

Military SONAR - A threat to whales? - link to Guardian Interactive Guide