U.S. government may allow the use of a powerful new system despite
evidence that military sonar kills marine animals. For the last
several years the U.S. Navy has been moving ahead with plans to
deploy Low Frequency Active Sonar, or LFA -- a new extended-range
submarine-detection system that will introduce into the world's
oceans noise billions of times more intense than that known to disturb
The National Marine Fisheries Service has proposed issuing a permit
that would allow the Navy to proceed with LFA deployment and flood
the ocean with intense noise, while in the process to harass, injure,
or even kill marine mammals.
Undeniable evidence that high-power "active" sonar systems
can and do kill marine animals emerged in March 2000, when beach
strandings of four different species of whales and dolphins in the
Bahamas coincided with a Navy battle group's use of extremely loud
active sonar there. Despite efforts to save the whales, seven of
them died; A National Marine Fisheries Service and Navy investigation
established with virtual certainty a connection between the strandings
and the sonar -- and that active-sonar system put out mid-frequency
sound, which generally does not travel as far as LFA.
Although active sonar has been suspected in previous strandings,
analysis of the inner ears of several dead whales enabled scientists
to confirm, for the first time, the dangerous role of active sonar
to a level of certainty that even the Navy could not ignore. All
but one of the whales suffered hemorrhages in the inner ear, almost
certainly the result of a sonic blast.
According to the Navy, LFA functions much like a floodlight, allowing
its operator to peer enormous distances into the ocean in search
of enemy submarines. Each one of the system's long array of transmitters
can generate 215 decibels of sound, a level millions of times more
intense than is considered safe for human divers; after several
hundred meters, the sound waves produced by the array converge,
boosting the noise level to an equivalent of more than 240 decibels.
Thanks to all these converging sound waves, LFA can illuminate hundreds
of thousands of square miles of ocean at one time, enabling, for
example, a low-frequency signal in the southern Indian Ocean to
be detectable off the West Coast of the United States.
For years the Navy had been testing the LFA system in complete
secrecy and in violation of environmental laws. In 1995, NRDC brought
the sonar tests to light and demanded that the Navy comply with
federal and state statutes and disclose how the sonar would affect
marine mammals, sea turtles and other ocean species. As a result,
the Pentagon agreed to conduct a full-scale study of environmental
impacts before putting the LFA system into use across an estimated
80 percent of the world's oceans.
In late January, the Navy released its Environmental Impact Statement,
which according to law should be a "rigorous and objective
evaluation" of environmental risks. Yet the Navy's study fails
to answer the most basic questions about its controversial system:
How will LFA affect the long-term health and behavior of whales,
dolphins and hundreds of other species? Taking place as it does
over an enormous geographic area, what effect might it have on marine
According to the Navy's 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.
Whales use their exquisitely sensitive hearing to follow migratory
routes, locate one another over great distances, find food and care
for their young. Noise that undermines their ability to hear can
threaten their ability to function and survive. As one scientist
succinctly put it: "A deaf whale is a dead whale." But
what concerns marine scientists even more than short-term effects
on individual animals is the potential long-term impact that the
Navy's LFA system might have on the behavior and viability of entire
populations of marine mammals.
As Dr. Linda Weilgart, a leading expert in acoustic communication
among whales, wrote in an article published in the October 28, 1999
issue of the Christian Science Monitor: There are some technologies
that simply should never be used. The Navy's Low Frequency Active
Sonar (LFAS) program is one of these
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.)
The National Marine Fisheries Service was accepting public comments
through May 31, 2001, on whether to grant the Navy's LFA permit
request. A massive write-in campaign was mounted via the Internet
to oppose granting the Navy's application to deploy LFA sonar. It
remains to be seen what the outcome will be.
For further information:
Federation of American Scientists :
ENN News (1998):