Deep-Sea Research I
<a href="http://www.sciencedirect.com/science/journal/09670637";
rel="nofollow">http://www.sciencedirect.com/science/journal/09670637</a>
W.A. Watkins, M.A. Daher, J.E. George and D. Rodriguez. 2004. Twelve
years of tracking 52-Hz whale calls from a unique source in the North
Pacific. Deep-Sea Research I.
Abstract
A unique whale call with 50-52 Hz emphasis from a single source
has been tracked over 12 years in the central and eastern North
Pacific. These calls, referred to as 52-Hz calls, were monitored and
analyzed from acoustic data recorded by hydrophones of the US Navy
Sound Surveillance System (SOSUS) and other arrays. The calls were
noticed first in 1989, and have been detected and tracked since
1992. No other calls with similar characteristics have been identified
in the acoustic data from any hydrophone system in the North Pacific
basin. Only one series of these 52-Hz calls has been recorded at a
time, with no call overlap, suggesting that a single whale produced
the calls. The calls were recorded from August to February with most
in December and January. The species producing these calls is
unknown. The tracks of the 52-Hz whale were different each year, and
varied in length from 708 to 11,062 km with travel speeds ranging from
0.7 to 3.8 km/h. Tracks included (A) meandering over short ranges, (B)
predominantly west-to-east movement, and (C) mostly north-to-south
travel. These tracks consistently appeared to be unrelated to the
presence or movement of other whale species (blue, fin and humpback)
monitored year-round with the same hydrophones.
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