When sound is dangerous

There are some technologies that simply should never be used. The Navy's Low Frequency Active Sonar (LFAS) program is one of these. It's a device the Navy has been developing since the late 1980s, which would allow it to detect newly quiet enemy submarines over great distances.

Speakers send out pulses of low frequency sonar that creates a powerful sound and pressure wave through the water. A similar LFAS system already has caused havoc underwater. A March 5, 1998, article in the journal Nature conclusively linked the operation of a LFAS system to a stranding of 13 Cuvier's beaked whales, which beached themselves and died, apparently as a panic reaction to the sound.

The Navy wants to deploy four LFAS-equipped ships around the world. Currently it is drafting an environmental impact statement for the National Marine Fisheries Service. (The fisheries service is taking public comment until Nov. 22.) Until the Navy can prove this system is safe for underwater life - and it probably can't - use of LFAS should be banned.

Sound travels very efficiently in water, and the lives of fish and whales revolve around sound. They use sound to feed, mate, navigate, detect predators, and communicate with one another.

Use of LFAS could well alter hearing ability in whales and other marine animals over a 15-mile radius, and could cause profound behavioral disturbance over an area bigger than Texas.

The Navy says it has proven through its own studies that LFAS has no significant impact on any marine animal. But its studies were carried out over a matter of weeks on only four species. Its study did not include the deep divers such as the Cuvier's beaked whale, which are thought to be most at risk because the sound is loudest down deep. The Navy's claim is simply ludicrous.

I have studied whale communication for 17 years. I know how difficult it is to study whales in the wild. Painstaking research over many years yields only the tiniest glimpse of whales' lives.

The Navy has studied only short-term, observable reactions, which are all but meaningless. The most significant impacts are on whole populations. (Incidentally, most US marine mammal scientists studying sounds rely heavily on US Navy funding.)

To determine the health of a population (that is, whether it will survive), we need detailed, accurate population size figures, birth rates, death rates, and growth rates. We have none of these statistics for almost any whale or dolphin population likely to be affected by LFAS. We don't even know which sounds the great whales can hear.

The Navy is trying to dilute by a factor of a million the acoustic harassment standards - a benchmark for determining the level at which marine animals suffer disturbance from sound. The upshot is, the effect of LFAS would appear not to be ocean-basin-wide, but relatively minor and localized. LFAS isn't just a localized phenomenon. Large parts of an ocean basin could be affected.

There are far too many critical issues to address before the Navy should go forward with use of this sonar technology. No one has even studied the ecological impact of using LFAS.

I am concerned that the sounds will interfere with whales' ability to: find mates over long distances (which would affect reproduction); listen to the quiet sounds emitted by predators and prey; detect beaches and avoid stranding themselves or getting tangled in fishing gear; stay with members of the group; stay in contact with their calves; and avoid the reaction (probably of panic) that has already been demonstrated with the Cuvier's beaked whales.

The burden of proof is on the Navy. The absence of proof (of impact) is not the same as the proof of absence (of impact). So far, the Navy has failed abysmally to provide any such assurance - nor can it, given our profound ignorance of whales. Therefore, the LFAS program should be halted.

While the Navy rolls out its newest military toy, arguing (questionably) that it is indispensable, our oceans will be dying the slow death of a thousand cuts. The ocean gives us our air, our water, our food, and regulates our climate. The ocean literally enables human life.

As a scientist - and as a mother and fellow inhabitant of this fragile planet - I am alarmed at this new threat to our oceans. I cannot imagine why we would subject marine inhabitants, the majority of which are highly sensitive to sound, to yet another source of pollution.

*Linda Weilgart, PhD, is a research associate at Dalhousie University, in Halifax, Nova Scotia. She is a leading expert in sperm whale accoustic communication.

(c) Copyright 1999. The Christian Science Publishing Society