Subject: Gray Whale Vocalizations

Jennifer D. Philips (jphilips@soest.hawaii.edu)
Sun, 26 Apr 1998 12:02:10 -1000

At 12:44 PM 4/26/98 -0700, you wrote:
>How far in the ocean can gray whale vocalization be heard?
>
>Dana Weld
>Cattail Creek School
>
>


Dana - 

That's a good question, because the vocalizations of gray whales are not as
popularly known as those of humpbacks and other whales.  But gray whales
are pretty vocal.  The vocalization sounds of the mysticete whales (baleen
whales) are generally classified into categories:  low moans, low grunts,
higher chirps/cries, and click-like sounds.  Gray whales have been observed
to produce 3 of these 4 types, all except the chirps/cries.  So, because
the whales produce those low frequency, long duration sounds, their sounds
most likely follow the same physical rules of acoustics as other low
frequency sounds.  In the ocean, a deep water channel called the SOFAR
channel has been theorized to carry low frequency sounds across huge
distances (such as across entire ocean basins), especially if the whale
produces the sound while in the channel, and a receiver whale is in the
channel at some distance away.  But because the channel is at about 800 m
depth, and because most whales probably do not dive quite this deep, their
sounds probably do not travel quite this far.  If the whale produces low
frequency moans and grunts at shallower depths, such as about 100-200m,
their sound might still travel as far away as 1000 km.  The truth is,
though, for gray whales, we just do not know for sure.  

Hope this answers your question!  And, write back if you have any more
questions.

Jen Philips
jphilips@soest.hawaii.edu
__________________________________

Jennifer D. Philips		
jphilips@soest.hawaii.edu

Marine Mammal Research Program
HIMB, University of Hawaii at Manoa
PO Box 1106			
Kailua, HI  96734
voice:  (808) 247-5063
fax: (808) 247-5831
__________________________________