Analysis of humpback whale sounds in shallow waters of the Southeastern Arabian Sea: An indication of breeding habitat.
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Date
2015-06
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Abstract
The primary objective of this work was to present the acoustical identification of humpback whales, detected by using
an autonomous ambient noise measurement system, deployed in the shallow waters of the Southeastern Arabian Sea
(SEAS) during the period January to May 2011. Seven types of sounds were detected. These were characteristically
upsweeps and downsweeps along with harmonics. Sounds produced repeatedly in a specific pattern were referred to as
phrases (PQRS and ABC). Repeated phrases in a particular pattern were referred to as themes, and from the
spectrographic analysis, two themes (I and II) were identified. The variation in the acoustic characteristics such as
fundamental frequency, range, duration of the sound unit, and the structure of the phrases and themes are discussed.
Sound units were recorded from mid-January to mid-March, with a peak in February, when the mean SST is ~28°C,
and no presence was recorded after mid-March. The temporal and thematic structures strongly determine the functions
of the humpback whale song form. Given the use of song in the SEAS, this area is possibly used as an active breeding
habitat by humpback whales during the winter season.
Description
Keywords
Acoustic parameters, breeding habitat, humpback whale, phrases, sound units, thematic structure
Citation
Mahanty Madan M, Latha G, Thirunavukkarasu A. Analysis of humpback whale sounds in shallow waters of the Southeastern Arabian Sea: An indication of breeding habitat. Journal of Biosciences. 2015 June; 40(2): 407-417.