Low frequency sounds

From: Howard Garrett (tokitae@pugetsound.net)
Date: Tue Feb 22 2000 - 13:26:04 EST


Hi Howard,

I have 2 questions:

1. Please advise me if there are any research papers on the subject of SLF
(super low frequency) sub-marine transmissions and marine mamal beachings.
I have a pet theory that a possible reason for the whale beachings is due to
the widespread use of SLF in Naval communications to submarine fleets. I cite
an example of a few years back here in the Monterey Bay, CA. Some
Navy/subcontractors were experimenting with new forms of SLF. I then read a
week or so later that due to the 'coincidence' of 2 whales beaching during
testing that the tests were suspended. Unfortunately I do not have a
reference to the news paper articles but it was probably the Santa Cruz
Sentinal within the last 5 years. My theory is simply that the high energy
SLF signals broadcast out over hundreds of miles of Ocean are literally
deafening the whales when they stray too close to a transmission station. Or
should I say when man builds the transmission stations close to whales. In a
bid to avoid the painful noise they then beach themselves. I would expect to
see statistically significant correlation of the locations of whale beachings
when analysed by the location of Navy SLF transmission stations or other
sources of SLF. The main problem with this is that the location of the SLF
transmission stations is probably classified as secret.

2. I am also interested in any links to online information on (1) above or on
Blue whale neurology.

If you feel unable to answer my questions would you be able to refer me to
someone who would be more appropriate.

Yours respectfully,

Nick

Dear Nick,

        Below is a CNN report of the problems associated with low frequency
broadcasts. There is also an incredibly comprehensive website on the Navy's
low frequency broadcasts at www.angelfire.com/ca/fishattorney/lfaslinks.html.

I am not aware of where to find online information on Blue whale neurology,
but I'd suggest a search of WhaleNet and the web.

Low-frequency sonar raises whale advocates' hackles
June 30, 1999
The low-frequency lowdown

The noise about noise

Beached whales, dead whales

Avoidance

Part I of a three-part series

By Stephanie Siegel
CNN Interactive Editor

(CNN) -- "Our whales didn't come back this year," said Capt. "China Mike"
Yee, easing the Lana Kila tour boat along Hawaii's aquamarine Kona coast.
"Not since the Navy did their sonar testing here."

The Navy disputes his assessment, saying this year's humpback whale season
was normal, and more whales than ever before were seen in March 1998, when
biologists studied humpbacks' response to the Navy's Low-Frequency Active
Sonar (LFAS) equipment in Hawaiian waters.

Whales use their ears to get around in the dark depths. Beaming sound into
their world is like shining bright lights at us. Scientists don't know what
harm, if any, it may do.

The Natural Resources Defense Council, which released its "Sounding the
Depths" report Monday, pushed the Navy to find out before putting the new
submarine-detection system to work.

The first two phases of Navy-funded testing (on blue, finback and gray
whales) started in fall 1997 off California. An Environmental Impact
Statement based on that and the Hawaii research will be published soon in
the Federal Register. The public will have 45 to 60 days to comment.

Meanwhile, the House Subcommittee on Fisheries Conservation, Wildlife and
Oceans began hearings Tuesday on the effectiveness of the 1972 Marine
Mammal Protection Act to evaluate what changes should be enacted during
this year's reauthorization.

And another sonar project is holding four public meetings that began
Tuesday in Kauai, Hawaii. The Acoustic Thermometry of Ocean Climate (ATOC)
project is asking to extend its two-year permit to operate low-frequency
sonar under the water off Kauai another five years.

There will be opposition. Some scientists and environmentalists say the
environmental impact studies are so narrow that they are meaningless. And
the whales may be in danger.

Humpback whale breeding grounds once could be found in any ocean. For a
variety of reasons, including formerly unrestrained whale hunting, now
there are three separate, reproductively isolated groups in the Pacific,
Atlantic and Southern oceans. All are endangered. Blue, fin and sperm
whales are endangered, too. The gray whale's environmental status is
"monitored."

The low-frequency lowdown
Protesters, who swam near the research vessel trying to stop the Hawaii
LFAS tests, doubt the Navy has prepared its Environmental Impact Statement
in good faith. After spending more than $200 million on LFA research and
development, they say, the Navy is committed to use it.

But Navy program manager Joe Johnson says the Navy would not implement a
system if it violated environmental laws. Independent experts from Cornell
University and Woods Hole Oceanographic Institution were hired to conduct
the research to assure believable results. "These guys are extremely
committed to the welfare and well-being of the animals," Johnson said.

A 200 decibel sound would fade to 140 decibels at a distance of 1,000
yards, the Navy's research team estimated. It fades more slowly, though,
when it bounces off the ocean bottom or surface or off the sides of one of
the natural "sound channels" in the oceans.
Ships have used sonar since World War II. Passive sonar listening devices
have been outdated by technologies that make submarines quieter. That's why
the Navy developed "active" sonar to send out sounds that reflect off
submarines, instead of waiting till the subs are close enough to hear.

Military, commercial, even recreational boats active sonars ping every nine
to 15 seconds, sounding the depths. They already create noise pollution in
lakes, ports and shipping lanes.

Low-frequency sound (below 1,000 hertz) goes farther. You may not be able
to hear the singers on your neighbor's stereo, but you can hear the bass.

ATOC uses the ocean's natural channels to transmit low frequency thousands
of kilometers. Sound travels slightly faster in warmer water. Scientists
believe that by measuring how fast sound travels across the cooler "Deep
Sound Channel" in comparison with its speed in other parts of the ocean,
they can detect a global warming trend.

The noise about noise
Whales sing low and loud. Their sounds travel thousands of miles. Blue
whales off Newfoundland can be heard in Puerto Rico, said Dr. Christopher
W. Clark, a principal investigator of both ATOC and LFA's mammal research.
Not by humans, whose ears are made for air and who rely more on vision
anyway, but by sonar detectors, and presumably by whales.

Whales depend on hearing the way humans depend on sight. They use their
sonar to find food, detect enemies, attract mates and know where their
children are.

Scientists say low-frequency sonar, if loud enough, has the potential to
drown out the whales so they can't hear what they need to. Whales listening
intently for the quiet swish of a school of fish may go hungry. A
3-month-old whale who leaves his mother's side to begin to explore his
world may not hear her calling to him and may never find her again.

It could do other damage, too.

Very loud sounds can rip ear, lung and other vibrating tissues. A sound
wave is a pressure wave; that's why you can sometimes feel your body
vibrate during loud, low sounds. When body tissues resonate with the
sound's frequency, the pressure increases.

The impact of a sonic disturbance varies with the animal's distance from
the sound source.

Repeated exposure to moderately loud sounds can damage human ears, as rock
musicians have learned.

Even milder sounds can be annoying, stressful, distracting (picture the
golfer about to swing) or confusing. Some sounds attract whales toward
boats, making them more vulnerable to collision.

Sometimes whales fall silent. Sperm and pilot whales stopped "singing"
(using their active sonar) altogether during a 220 decibel test in 1991,
some of them for days, which meant they were not eating during that time.

Whales may fall silent to hide from their sharp-eared predators (killer
whales, or orcas). Because silence evolved as their survival response, they
hush at any strange noise.

When they're not using their active sonar, whales are not courting
potential mates, and they may not be finding food. Deep-water whales, the
kind with teeth, are thought to use echolocation (active sonar) for
navigation and hunting.

Sounds booming at regular intervals also could interfere with whales'
sleep. Little is known about how whales and dolphins sleep, except that
they must surface to breathe. "In humans, prolonged or repeated noises can
cause difficulties in falling asleep, changes in sleep patterns, and
awakenings," says the often-cited book "Marine Mammals and Noise" by W.
John Richardson et al.

Chronic noise may lead to high blood pressure in humans, and strong noise
can affect reproduction and rearing of young in land animals, Richardson's
book adds.

Repeated stress can take a toll on an animal's immune system, leaving it
more vulnerable to parasites and other infections.

Extreme stress or panic may cause whales to lose their way and wash up on
beaches; or their disorientation may result from damage to their hearing or
another aspect of their navigational sonar system.

Beached whales, dead whales
In a 1998 Nature article, Alexandros Frantzis pointed out that 12 Cuvier's
beaked whales beached themselves alive on a Mediterranean coast while ATO
was testing LFAS there. He concluded the chance of that happening for any
other reason was less than 0.07 percent. The U.S. Navy research vessel
Alliance performed that test for NATO but at a higher frequency than the
United States used, said the Navy's Johnson.

Scatterplots from the Hawaii LFA study show the distribution of whales
around the ship. Click on buttons to show change.
Ten gray whale calves stranded alive in California in January-February 1998
(during and after LFA tests there), an abnormally high number, said
EnviroWatch Inc.

Two dead whales were seen near the Kauai ATOC source in November and
December 1997, the Cetacean Society International reported.

Three humpback whales died in northern California in November 1995 within a
week after the ATOC equipment was turned on for engineering tests -- before
the formal program to monitor mammals began. But the project resumed
"following a determination that it was highly unlikely the test
transmissions could have been responsible," the Marine Mammal Commission
reported.

Avoidance
Whales have altered their migration routes to avoid noise louder than 120
decibels, research has shown.

Whales moved away from the LFA ship during the March 1998 Hawaii tests, but
the research team said that was their normal migration pattern. The
humpbacks were just heading north and east as other studies have shown they
do every March, their preliminary "Quicklook" report said.

Gray whales moved more than a kilometer to avoid a 185-decibel sound source
in the California test.

One ATOC bimonthly report counted 1,754 animals when the sonar was off and
138 animals when it was on. Other ATOC reports said sperm whale sightings
decreased 90 percent, and humpbacks were seen an average of one to two
nautical miles farther away from the sound source when it was on than when
it was off. The average distance for all sperm whale groups was greater
when the sound was on, but "it does not have a strong causal linkage to
acoustics," the scientists reported.

Whales may be in even greater danger when they show no immediate response.

A 1993 report on oil drilling and explosions in the Journal of the
Acoustical Society of America found humpback whales with severely damaged
ears similar to blast injuries in humans. But the whales had shown only
small changes in movements and behavior -- no dramatic reaction to the
sound. The authors cautioned that whales' visible short-term reaction to
loud sound may not be a valid measure of its impact on them.

"We should be just as concerned about the marine mammal that becomes
habituated to the sound and presses on regardless, or that willfully
suffers discomfort to remain in prosperous waters," said the Natural
Resources Defense Council in its report.

-------------------------------
Howard Garrett
Tokitae Orca Conservation Foundation
2403 So. North Bluff Rd.
Greenbank WA 98253
(360) 678-3451
mailto:tokitae@pugetsound.net
http://www.rockisland.com/~tokitae/
http://www.freelolita.net



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