On behalf of my co-authors,
I am thrilled to announce the publication of our new paper,
"Source level and vocalizing depth estimation of two blue whale subspecies in the western Indian Ocean from single sensor observations".
,
"Source level and vocalizing
depth estimation of two blue whale subspecies in the western Indian Ocean from single sensor observations",
The Journal of the Acoustical Society of America 149,
4422-4436 (2021)
Please feel free to email me for a pdf copy at lea.bouffaut@ntnu.no
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Abstract
The source level (SL) and vocalizing source depth (SD) of individuals from two blue whale (BW) subspecies, an Antarctic blue whale (Balaenoptera
musculus intermedia; ABW) and a Madagascar pygmy blue whale (Balaenoptera musculus brevicauda;
MPBW) are estimated from a single bottom-mounted hydrophone in the western Indian Ocean. Stereotyped units (male) are automatically detected and the range is estimated from the time delay between the direct and lowest-order multiply-reflected acoustic paths
(multipath-ranging). Allowing for geometric spreading and the Lloyd's mirror effect (range-, depth-, and frequency-dependent) SL and SD are estimated by minimizing the SL variance over a series of units from the same individual over time (and hence also range).
The average estimated SL of 188.5 ± 2.1 dB re. 1μPa measured
between [25–30] Hz for the ABW and 176.8 ± 1.8 dB re. 1μPa measured
between [22–27] Hz for the MPBW agree with values published for other geographical areas. Units were vocalized at estimated depths of 25.0 ± 3.7 and 32.7 ± 5.7 m for the ABW Unit A and C and, ~20m for
the MPBW. The measurements show that these BW calls series are stereotyped in frequency, amplitude, and depth.
Léa Bouffaut
Post-doctoral fellow, Ph.D.
Norwegian University of Science and Technology
Department of Electronic Systems
O.S. Bragstads plass 2b | Gløshaugen, Trondheim