Subject: Info: Noise Study on Stellwagen Bank.

Michael Williamson (pita)
Mon, 26 Jan 1996 09:06:16

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From: Michael Williamson <pita@whale.simmons.edu>
Subject: Info: Noise Study on Stellwagen Bank.
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---------- Forwarded message ----------
Date: Thu, 25 Jan 1996 12:42:47 EST
From: SCHEIFEL@UConnVM.UConn.Edu
To: Multiple recipients of list MARMAM <MARMAM@UVVM.BITNET>
 
To the Community,
I thought that a few comments regarding the article in the Portland Press Heral
d concerning noise and whales in the Gulf of Maine might put things into perspe
ctive.  The article sounds a bit more frantic in some areas than it ought to be
.  The work was done in a very short time in only one location by a group of se
condary school students consequently it is very rudimentary and preliminary.
The article specifically targets fishing vessels when, in fact many other sourc
es of noise were included.  Nowhere in the article does it specify that the ani
mals dirctly inhabiting Stellwagen Bank were exhibiting any gross behaviours
that related to the noise.  One of the great problems with in-situ bioacoustics
is that there is literally no good way of determining whether a behaviour perfo
rmed by a specific animal is acoustically related.  Neverthless acoustic behavi
ours have been elicited and recorded in many areas of the world including Stell
wagen Bank on rare occasions.
 
Studies (performed by myself and others) do indicate that using an A-weighted s
cale and the conditions of background noise in Stellwagen Bank the human ear wo
uld undergo some short-term related damage; hence the OSHA standards for simila
r noise levels in work places.  What makes this study unique is 1) the people p
erforming it and 2) the fact that they made some acceptable inferrences based u
pon human hearing versus that of cetaceans.
 
Finally (and perhaps most important) we should not become overly frantic in eit
her direction (that we are deafening the animals or not affecting them in any w
ay) until we learn more about 1) their specific hearing abilities,  2) what act
ual noise levels are in the acoustic environments in which they live,  3)wheth
er the environments are noise limited or reverberation limited,  4) whether the
y are specifically subject to noise that is persistant or transient, and 5) wha
t the specific hearing sensitivities are by species.
 
I don't believe that it is truly possible to determine with certainty whether a
ny marine mammal is sensitive or oblivious to background noise in the wild envi
ronment based upon alleged "acoustical behaviour" at present since the situatio
n cannot be adequately controlled to make those kinds of decisions.
 
Your discussion is delightful and welcomed.  We are continuing our studies of t
he effects of low frequency noise on cetaceans in the Gulf of Maine and the Sai
nt Lawrence estuary (here at the National Undersea Research Center at the Unive
rsity of Connecticut, Avery Point).
 
Regards,
Peter M. Scheifele
Bioacoustician