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Malige F, Patris J, Hauray M, Giraudet P, Glotin H. Mathematical models of long term evolution of blue whale song types' frequencies. J Theor Biol 2022; 548:111184. [PMID: 35697145 DOI: 10.1016/j.jtbi.2022.111184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 05/26/2022] [Accepted: 05/31/2022] [Indexed: 10/18/2022]
Abstract
The linear decrease in the frequency of blue whale songs around the world is, to date, an unexplained phenomenon. We show it can be reproduced by a mathematical model considering two antagonistic behavioral trends: first, a bias towards conformity in the song, and second, a tendency to try and sing lower than the other whales. We check the robustness of our model by considering some more complex premises. First, different hierarchical relations between the singers are explored, adapting methods used in the flocking motion studies. Then a population-dependant simulation shows that even considering the gradual addition of new whales, the evolution is still globally linear. Finally, we show that intra-annual variations surging from different causes can be naturally incorporated into the model. We then conclude that, unlike other explanations, a cultural hypothesis seems compatible with the observed linearity of the blue whales's songs frequency shift.
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Affiliation(s)
- Franck Malige
- DYNI team, LIS laboratory, Université de Toulon, Campus de La Garde, Bat. X, CS 60584, 83041 Toulon Cedex 9, France.
| | - Julie Patris
- Faculté des sciences, université d'Aix-Marseille, site Montperrin, 6 avenue du Pigonnet, 13090 Aix en Provence, France.
| | - Maxime Hauray
- Institut de mathématiques de Marseille, université d'Aix-Marseille, Technopole Chateau-Gombert, 39 rue F. Joliot Curie, 13453 Marseille Cedex 13, France.
| | - Pascale Giraudet
- DYNI team, LIS laboratory, Université de Toulon, Campus de La Garde, Bat. X, CS 60584, 83041 Toulon Cedex 9, France.
| | - Hervé Glotin
- DYNI team, LIS laboratory, Université de Toulon, Campus de La Garde, Bat. X, CS 60584, 83041 Toulon Cedex 9, France.
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Bouffaut L, Landrø M, Potter JR. 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 2021; 149:4422. [PMID: 34241450 DOI: 10.1121/10.0005281] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 05/24/2021] [Indexed: 06/13/2023]
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, ≃20 m for the MPBW. The measurements show that these BW calls series are stereotyped in frequency, amplitude, and depth.
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Affiliation(s)
- Léa Bouffaut
- Department of Electronic Systems, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway
| | - Martin Landrø
- Department of Electronic Systems, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway
| | - John R Potter
- Department of Electronic Systems, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway
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Multiple pygmy blue whale acoustic populations in the Indian Ocean: whale song identifies a possible new population. Sci Rep 2021; 11:8762. [PMID: 33888792 PMCID: PMC8062560 DOI: 10.1038/s41598-021-88062-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 03/22/2021] [Indexed: 11/29/2022] Open
Abstract
Blue whales were brought to the edge of extinction by commercial whaling in the twentieth century and their recovery rate in the Southern Hemisphere has been slow; they remain endangered. Blue whales, although the largest animals on Earth, are difficult to study in the Southern Hemisphere, thus their population structure, distribution and migration remain poorly known. Fortunately, blue whales produce powerful and stereotyped songs, which prove an effective clue for monitoring their different ‘acoustic populations.’ The DGD-Chagos song has been previously reported in the central Indian Ocean. A comparison of this song with the pygmy blue and Omura’s whale songs shows that the Chagos song are likely produced by a distinct previously unknown pygmy blue whale population. These songs are a large part of the underwater soundscape in the tropical Indian Ocean and have been so for nearly two decades. Seasonal differences in song detections among our six recording sites suggest that the Chagos whales migrate from the eastern to western central Indian Ocean, around the Chagos Archipelago, then further east, up to the north of Western Australia, and possibly further north, as far as Sri Lanka. The Indian Ocean holds a greater diversity of blue whale populations than thought previously.
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Malige F, Patris J, Buchan SJ, Stafford KM, Shabangu F, Findlay K, Hucke-Gaete R, Neira S, Clark CW, Glotin H. Inter-annual decrease in pulse rate and peak frequency of Southeast Pacific blue whale song types. Sci Rep 2020; 10:8121. [PMID: 32415228 PMCID: PMC7229211 DOI: 10.1038/s41598-020-64613-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 04/14/2020] [Indexed: 11/09/2022] Open
Abstract
A decrease in the frequency of two southeast Pacific blue whale song types was examined over decades, using acoustic data from several different sources in the eastern Pacific Ocean ranging between the Equator and Chilean Patagonia. The pulse rate of the song units as well as their peak frequency were measured using two different methods (summed auto-correlation and Fourier transform). The sources of error associated with each measurement were assessed. There was a linear decline in both parameters for the more common song type (southeast Pacific song type n.2) between 1997 to 2017. An abbreviated analysis, also showed a frequency decline in the scarcer southeast Pacific song type n.1 between 1970 to 2014, revealing that both song types are declining at similar rates. We discussed the use of measuring both pulse rate and peak frequency to examine the frequency decline. Finally, a comparison of the rates of frequency decline with other song types reported in the literature and a discussion on the reasons of the frequency shift are presented.
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Affiliation(s)
- Franck Malige
- Univ. Toulon, Aix Marseille Univ., CNRS, LIS, DYNI team, SABIOD, Marseille, France.
| | - Julie Patris
- Univ. Toulon, Aix Marseille Univ., CNRS, LIS, DYNI team, SABIOD, Marseille, France
| | - Susannah J Buchan
- COPAS Sur-Austral, Edificio Departamento de Oceanografía Piso 2 Barrio Universitario s/n, Universidad de Concepción, Concepción, Chile.,Centro de Estudios Avanzados en Zonas Áridas, Avenida Ossandón 877, Coquimbo, Región de Coquimbo, Chile.,Woods Hole Oceanographic Institution, Biology Department, Woods Hole, Massachusetts, 02543, USA
| | - Kathleen M Stafford
- Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Box 355640, Seattle, Washington, 98105, USA
| | - Fannie Shabangu
- Fisheries Management, Department of Agriculture, Forestry and Fisheries, Private Bag X2, Vlaeberg, Cape Town, 8012, South Africa.,Mammal Research Institute Whale Unit, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - Ken Findlay
- Mammal Research Institute Whale Unit, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa.,Cape Peninsula University of Technology, P.O. Box 652, Cape Town, 8000, South Africa
| | - Rodrigo Hucke-Gaete
- Instituto de Ciencias Marinas y Limnologicas, Universidad Austral de Chile, Campus Isla Teja, Valdivia, Chile
| | - Sergio Neira
- COPAS Sur-Austral, Edificio Departamento de Oceanografía Piso 2 Barrio Universitario s/n, Universidad de Concepción, Concepción, Chile
| | - Christopher W Clark
- Bioacoustics Research Program, Cornell Laboratory of Ornithology, Cornell University, Ithaca, New York, 14850, USA
| | - Hervé Glotin
- Univ. Toulon, Aix Marseille Univ., CNRS, LIS, DYNI team, SABIOD, Marseille, France
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Guilment T, Socheleau FX, Pastor D, Vallez S. Sparse representation-based classification of mysticete calls. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 144:1550. [PMID: 30424647 DOI: 10.1121/1.5055209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 08/28/2018] [Indexed: 06/09/2023]
Abstract
This paper presents an automatic classification method dedicated to mysticete calls. This method relies on sparse representations which assume that mysticete calls lie in a linear subspace described by a dictionary-based representation. The classifier accounts for noise by refusing to assign the observed signal to a given class if it is not included into the linear subspace spanned by the dictionaries of mysticete calls. Rejection of noise is achieved without feature learning. In addition, the proposed method is modular in that, call classes can be appended to or removed from the classifier without requiring retraining. The classifier is easy to design since it relies on a few parameters. Experiments on five types of mysticete calls are presented. It includes Antarctic blue whale Z-calls, two types of "Madagascar" pygmy blue whale calls, fin whale 20 Hz calls and North-Pacific blue whale D-calls. On this dataset, containing 2185 calls and 15 000 noise samples, an average recall of 96.4% is obtained and 93.3% of the noise data (persistent and transient) are correctly rejected by the classifier.
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Affiliation(s)
- Thomas Guilment
- IMT Atlantique, Lab-STICC, Bretagne Loire University, Technopole Brest-Iroise CS83818, Brest 29238, France
| | - Francois-Xavier Socheleau
- IMT Atlantique, Lab-STICC, Bretagne Loire University, Technopole Brest-Iroise CS83818, Brest 29238, France
| | - Dominique Pastor
- IMT Atlantique, Lab-STICC, Bretagne Loire University, Technopole Brest-Iroise CS83818, Brest 29238, France
| | - Simon Vallez
- Sercel, 12 Rue de la Villeneuve, 29200 Brest, France
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Bouffaut L, Dréo R, Labat V, Boudraa AO, Barruol G. Passive stochastic matched filter for Antarctic blue whale call detection. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 144:955. [PMID: 30180699 DOI: 10.1121/1.5050520] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 07/26/2018] [Indexed: 06/08/2023]
Abstract
As a first step to Antarctic blue whale (ABW) monitoring using passive acoustics, a method based on the stochastic matched filter (SMF) is proposed. Derived from the matched filter (MF), this filter-based denoising method enhances stochastic signals embedded in an additive colored noise by maximizing its output signal to noise ratio (SNR). These assumptions are well adapted to the passive detection of ABW calls where emitted signals are modified by the unknown impulse response of the propagation channel. A filter bank is computed and stored offline based on a priori knowledge of the signal second order statistics and simulated colored sea-noise. Then, the detection relies on online background noise and SNR estimation, realized using time-frequency analysis. The SMF output is cross-correlated with the signal's reference (SMF + MF). Its performances are assessed on an ccean bottom seismometer-recorded ground truth dataset of 845 ABW calls, where the location of the whale is known. This dataset provides great SNR variations in diverse soundscapes. The SMF + MF performances are compared to the commonly used MF and to the Z-detector (a sub-space detector for ABW calls). Mostly, the benefits of the use of the SMF + MF are revealed on low signal to noise observations: in comparison to the MF with identical detection threshold, the false alarm rate drastically decreases while the detection rate stays high. Compared to the Z-detector, it allows the extension of the detection range of ≃ 30 km in presence of ship noise with equivalent false discovery rate.
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Affiliation(s)
- Léa Bouffaut
- Institut de Recherche de l'Ecole Navale, EA3634, Ecole Navale/Arts et Metiers ParisTech, BCRM Brest CC600, 29240 Brest Cedex 9, France
| | - Richard Dréo
- Institut de Recherche de l'Ecole Navale, EA3634, Ecole Navale/Arts et Metiers ParisTech, BCRM Brest CC600, 29240 Brest Cedex 9, France
| | - Valérie Labat
- Institut de Recherche de l'Ecole Navale, EA3634, Ecole Navale/Arts et Metiers ParisTech, BCRM Brest CC600, 29240 Brest Cedex 9, France
| | - Abdel-O Boudraa
- Institut de Recherche de l'Ecole Navale, EA3634, Ecole Navale/Arts et Metiers ParisTech, BCRM Brest CC600, 29240 Brest Cedex 9, France
| | - Guilhem Barruol
- Institut de Physique du Globe de Paris, Sorbonne Paris Cite, UMR 7154 CNRS, 1 rue Jussieu, 75238 Paris Cedex 05, France
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