whales/submarine sound sources

wolfgang kusser wkusser at sol.uvic.ca
Thu Feb 3 15:06:17 EST 1994


I received the following message on the marine mammals list. With permission
of Lindy I forward this message and two corrections:

>Sender: Marine Mammals Research and Conservation Discussion
>              <MARMAM at UVVM.BITNET>
>From: Lindy Weilgart/ Hal Whitehead <HWHITEHE at AC.DAL.CA>
>Subject:      ATOC loud sounds
>X-To:         marmam at uvvm.uvic.ca
>To: Multiple recipients of list MARMAM <MARMAM at UVVM.BITNET>
>I am quite concerned that the following issue has not received the
>necessary publicity to lend itself to healthy dialog about this matter.
>I am referring to two extremely loud sound sources that are starting
>operation this month and next month, off 1) Kauai, Hawaii and 2) Pt. Sur,
>California, which is an especially productive area rich in marine mammal
>life.  The speakers are to be placed at a depth of about 700-800 m just off
>the coast of these two locations.  The intensity of these sound sources will
>be about 195 dB.  This is about 10,000,000 times 120 dB (dB is a logarithmic
>scale).  120 dB is the level of intensity at which even the comparatively
>acoustically insensitive grey whale avoids noise.  120 dB is also the threshold
>of pain for humans for airborne sound.  The sound sources will be broadcasting
>a fairly low-pitched sound, 70 Hz in frequency (human hearing extends down to
>20 Hz).  The sounds will remain on for a duration of 20 min, off for 4 hrs,
>on for 20 min., etc. for the next few years at least and probably decades.
>Sound sources like these are also proposed for the Atlantic and Indian oceans
>as well, effectively assaulting the oceans of the world for the next decade
>with noise.  The sounds are loud enough to travel halfway around the world
>using the deep sound channel.
>    The "ATOC" (Acoustic Thermography of Global Ocean Climate) Project's
>purpose is supposedly to examine global temperature trends in the ocean,
>as a way to monitor global warming, since the speed of sound increases with incr
>easing water temperature.  The multi-million dollar project is funded by
>the U.S. Dept. of Defense (ARPA).  Many climatologists question whether ATOC
>is the best way to gauge global warming, especially as the source is located
>so far (800 m) below the ocean surface.
>     As you know, whales, especially toothed whales, are critically dependent
>on sound, often both for social communication as well as for food-finding.
>Deep-diving whales are likely to be the species most affected by the sound.
>Sperm whales regularly dive to 400 m depths and beyond, bringing them into
>potentially close contact with the ATOC source.  They are also extremely
>acoustically sensitive, as anyone who has spent any time at all with them,
>knows.  Beaked whales could also be affected.  Humpback whales off Newfound-
>land have been found with shattered ear bones, likely as a result of sound
>levels that were thought to be much less intense than those used by ATOC.
>     Studies of the effects of ATOC's sound sources on marine mammals are
>being undertaken by ATOC.  Unfortunately, these studies commence at roughly
>the same time as the ATOC source begins operation, enabling little or no
>baseline information to be gathered.  It will be very hard to document any
>clear disturbance since effects on marine mammals could be occurring beyond
>the horizon from the source or at great depth.  In addition, it will be
>almost impossible to ascertain whether whales will be suffering habitual
>hearing impairment.  If whales are gradually being deafened by the sound
>source, they will show less and less disturbance from the sound over time,
>leading to erroneous conclusions of "no adverse effects".  Alternatively,
>one blast of 195 dB may be enough to permanently damage the hearing (or
>cause other physiological damage), invalidating any results that occur
>subsequently.  WE JUST DO NOT KNOW, NOR ARE WE LIKELY TO FIND THIS OUT GIVEN THE
> DIFFICULTY OF STUDYING SPERM WHALES, ESPECIALLY AT DEPTH OR BEYOND THE
>HORIZON.  Tags will hopefully help in answering this question, but as the
>source cannot be moved, will provide few test cases.  (0ne has to wait until
>a tagged whale passes by at relatively close distance to the speaker).  The
>potential psychological stress of a sound that is regularly on for 20 min at
>a time around the clock for years and years will be even more impossible to
>evaluate.
>     The feasibility test for ATOC was conducted off Heard Island on an even
>greater intensity level (around 215 dB) in 1991.  This was done without filing
>permits for marine mammals, and the sound was heard 18,000 km away in Bermuda
>WITHOUT SIGNAL PROCESSING OR FILTERING NEEDED.  One wonders why such a loud
>sound was needed.
>     In conclusion, the most alarming aspect of this project is the dearth
>of publicity it has received, considering its far-ranging potential implications
> for marine mammals and marine life in general.  The permits for the two sound
>sources were filed and the Hawaii one has gone though a 30 day public comment
>period on the Federal Register with hardly any comments noted!  The California
>30-day period on the Federal Register is happening now, I think.  Please
>give comments to NMFS or the Marine Mammal Commission SOON!
>     Lindy Weilgart and Hal Whitehead
NEW MESSAGE:
.....stuff deleted....
>Apparently, there
>are two corrections to make.  There apparently were some baseline studies
>but I am not aware they were done on sperm whales and it certainly wasn't an
>intensive effort.  No attempt has been made to broadcast the sounds in a
>more experimental setting, i.e. starting at a much lower level and only
>turned on when the research animals were in the area.  This desperately needs
>to be done before the source is turned on in earnest (at proposed level and
>duty cycle of 20 min. on 4 hrs off).  One other correction: the Heard Island
>study did have a permit, but many people agree that this was in name only--
>woefully inadequate.  It definitely was rushed and pushed through prematurely.



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