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Mishima Y, Matsuo I, Karasawa Y, Ishii M, Morisaka T. Directional and amplitude characteristics of pulsed call sequences in captive free-swimming Pacific white-sided dolphins (Lagenorhynchus obliquidens). THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 154:2974-2987. [PMID: 37947396 DOI: 10.1121/10.0022377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 10/24/2023] [Indexed: 11/12/2023]
Abstract
We investigated the directional properties and gain control of a pulsed call sequence that functions as a contact call in Pacific white-sided dolphins (Lagenorhynchus obliquidens). The pulsed call sequences were stereotyped patterns composed of three or more pulsed call elements and were collected from two dolphins, separated into adjacent pools, and allowed to swim freely. Eight hydrophones and an overhead camera were used to determine the positions and directions of the participants. The mean peak frequency and source levels were 8.4 ± 4.4 (standard deviation)-18.7 ± 12.7 kHz and 160.8 ± 3.8 to 176.4 ± 7.9 dB re 1 μPa (peak-to-peak), respectively, depending on the element types. The elements were omnidirectional, with mean directivity index of 0.9 ± 3.4 dB. The dolphins produced sequences, regardless of their relative position and direction to the lattice, leading to the adjacent pool where the conspecific was housed. They increased the amplitude by 6.5 ± 4.6 dB as the distance from the caller to an arbitrary point in the adjacent pool doubled. These results suggest that callers broadcast pulsed call sequences in a wide direction to reach dispersed conspecifics. However, they can adjust the acoustic active space by controlling the source levels.
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Affiliation(s)
- Yuka Mishima
- Department of Marine Resources and Energy, Tokyo University of Marine Science and Technology, 4-5-7, Konan, Minato-ku, Tokyo, 108-8477, Japan
| | - Ikuo Matsuo
- Department of Information Science, Tohoku Gakuin University, 2-1-1 Tenjinzawa, Izumi-ku, Sendai, 981-3193, Japan
| | - Yuu Karasawa
- Izu Mito Sea Paradise, 3-1, Nagahama, Uchiura, Numazu-shi, Shizuoka, 410-0295, Japan
| | - Marina Ishii
- Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7, Konan, Minato-ku, Tokyo, 108-8477, Japan
| | - Tadamichi Morisaka
- Cetacean Research Center, Graduate School of Bioresources, Mie University, 1577, Kurimamachiya-cho, Tsu-shi, Mie, 514-8507, Japan
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2
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Madsen PT, Siebert U, Elemans CPH. Toothed whales use distinct vocal registers for echolocation and communication. Science 2023; 379:928-933. [PMID: 36862790 DOI: 10.1126/science.adc9570] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
Echolocating toothed whales (odontocetes) capture fast-moving prey in dark marine environments, which critically depends on their ability to generate powerful, ultrasonic clicks. How their supposedly air-driven sound source can produce biosonar clicks at depths of >1000 meters, while also producing rich vocal repertoires to mediate complex social communication, remains unknown. We show that odontocetes possess a sound production system based on air driven through nasal passages that is functionally analogous to laryngeal and syringeal sound production. Tissue vibration in different registers produces distinct echolocation and communication signals across all major odontocete clades, and thus provides a physiological basis for classifying their vocal repertoires. The vocal fry register is used by species from porpoises to sperm whales for generating powerful, highly air-efficient echolocation clicks.
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Affiliation(s)
- Peter T Madsen
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, 25761 Büsum, Germany
| | - Coen P H Elemans
- Sound Communication and Behavior Group, Department of Biology, University of Southern Denmark, 5230 Odense M, Denmark
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3
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Malinka CE, Rojano-Doñate L, Madsen PT. Directional biosonar beams allow echolocating harbour porpoises to actively discriminate and intercept closely spaced targets. J Exp Biol 2021; 224:271830. [PMID: 34387665 DOI: 10.1242/jeb.242779] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/28/2021] [Indexed: 10/20/2022]
Abstract
Echolocating toothed whales face the problem that high sound speeds in water mean that echoes from closely spaced targets will arrive at time delays within their reported auditory integration time of some 264 µs. Here, we test the hypothesis that echolocating harbour porpoises cannot resolve and discriminate targets within a clutter interference zone given by their integration time. To do this, we trained two harbour porpoises (Phocoena phocoena) to actively approach and choose between two spherical targets at four varying inter-target distances (13.5, 27, 56 and 108 cm) in a two-alternative forced-choice task. The free-swimming, blindfolded porpoises were tagged with a sound and movement tag (DTAG4) to record their echoic scene and acoustic outputs. The known ranges between targets and the porpoise, combined with the sound levels received on target-mounted hydrophones revealed how the porpoises controlled their acoustic gaze. When targets were close together, the discrimination task was more difficult because of smaller echo time delays and lower echo level ratios between the targets. Under these conditions, buzzes were longer and started from farther away, source levels were reduced at short ranges, and the porpoises clicked faster, scanned across the targets more, and delayed making their discrimination decision until closer to the target. We conclude that harbour porpoises can resolve and discriminate closely spaced targets, suggesting a clutter rejection zone much shorter than their auditory integration time, and that such clutter rejection is greatly aided by spatial filtering with their directional biosonar beam.
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Affiliation(s)
- Chloe E Malinka
- Zoophysiology, Department of Biology, Aarhus University, Aarhus 8000, Denmark
| | - Laia Rojano-Doñate
- Zoophysiology, Department of Biology, Aarhus University, Aarhus 8000, Denmark
| | - Peter T Madsen
- Zoophysiology, Department of Biology, Aarhus University, Aarhus 8000, Denmark
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4
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Melo JF, Amorim TOS, Paschoalini M, Andriolo A. The biosonar of the boto: evidence of differences among species of river dolphins ( Inia spp.) from the Amazon. PeerJ 2021; 9:e11105. [PMID: 33981488 PMCID: PMC8071073 DOI: 10.7717/peerj.11105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 02/22/2021] [Indexed: 11/20/2022] Open
Abstract
Echolocation clicks can reflect the anatomy of the vocalizing animal, enabling the distinction of species. River dolphins from the family Iniidae are formally represented by one species and two subspecies (Inia geoffrensis geoffrensis and I. g. humboldtiana). Additionally, two other species have been proposed (I. boliviensis and I. araguaiaensis) regarding its level of restricted distribution and morph-genetics differences. For the Committee on Taxonomy of the Society for Marine Mammalogy, the specific status of the proposed species relies on further knowledge on morphology, ecology, and genetics. Given that species-specific status is required for conservation efforts, we described and compared the echolocation clicks of Inia spp., searching for specific differences on their vocalizations. The sounds were captured with a Cetacean Research ™ C54XRS (+3/−20 dB, −185 dB re: 1V/μPa) in Guaviare River (Orinoco basin), Madeira River (Madeira basin), Xingu River (Amazon Basin), and Araguaia River (Tocantins-Araguaia basin). We found significant differences in all analyzed parameters (peak frequency, 3 dB bandwidth, 10 dB bandwidth and inter-click interval) for all species and subspecies. Differences in acoustical parameters of clicks are mainly related to the animal’s internal morphology, thus this study may potentially support with information for the species-level classification mostly of I. araguaiaensis (the Araguaian boto). Classifying the Araguaian boto separately from I. geoffrensis has important implications for the species in terms of conservation status, since it is restricted to a highly impacted river system.
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Affiliation(s)
- Jéssica F Melo
- Laboratório de Ecologia Comportamental e Bioacústica - LABEC, Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil.,Grupo de Pesquisa em Mamíferos Aquáticos Amazônicos, Mamirauá Sustainable Development Institute, Tefé, Amazonas, Brazil
| | - Thiago O S Amorim
- Laboratório de Ecologia Comportamental e Bioacústica - LABEC, Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil.,Instituto Aqualie, Juiz de Fora, Minas Gerais, Brazil
| | - Mariana Paschoalini
- Laboratório de Ecologia Comportamental e Bioacústica - LABEC, Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil.,Grupo de Pesquisa em Mamíferos Aquáticos Amazônicos, Mamirauá Sustainable Development Institute, Tefé, Amazonas, Brazil.,Instituto Aqualie, Juiz de Fora, Minas Gerais, Brazil
| | - Artur Andriolo
- Laboratório de Ecologia Comportamental e Bioacústica - LABEC, Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil.,Instituto Aqualie, Juiz de Fora, Minas Gerais, Brazil
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5
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von Benda-Beckmann AM, Isojunno S, Zandvliet M, Ainslie MA, Wensveen PJ, Tyack PL, Kvadsheim PH, Lam FPA, Miller PJO. Modeling potential masking of echolocating sperm whales exposed to continuous 1-2 kHz naval sonar. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 149:2908. [PMID: 33940877 DOI: 10.1121/10.0004769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 04/02/2021] [Indexed: 06/12/2023]
Abstract
Modern active sonar systems can (almost) continuously transmit and receive sound, which can lead to more masking of important sounds for marine mammals than conventional pulsed sonar systems transmitting at a much lower duty cycle. This study investigated the potential of 1-2 kHz active sonar to mask echolocation-based foraging of sperm whales by modeling their echolocation detection process. Continuous masking for an echolocating sperm whale facing a sonar was predicted for sonar sound pressure levels of 160 dB re 1 μPa2, with intermittent masking at levels of 120 dB re 1 μPa2, but model predictions strongly depended on the animal orientation, harmonic content of the sonar, click source level, and target strength of the prey. The masking model predicted lower masking potential of buzz clicks compared to regular clicks, even though the energy source level is much lower. For buzz clicks, the lower source level is compensated for by the reduced two-way propagation loss to nearby prey during buzzes. These results help to predict what types of behavioral changes could indicate masking in the wild. Several key knowledge gaps related to masking potential of sonar in echolocating odontocetes were identified that require further investigation to assess the significance of masking.
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Affiliation(s)
- A M von Benda-Beckmann
- Acoustics and Sonar, Netherlands Organization for Applied Scientific Research (TNO), P.O. Box 96864, The Hague 2509 JG, The Netherlands
| | - S Isojunno
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, United Kingdom
| | - M Zandvliet
- Acoustics and Sonar, Netherlands Organization for Applied Scientific Research (TNO), P.O. Box 96864, The Hague 2509 JG, The Netherlands
| | - M A Ainslie
- JASCO Applied Sciences (Deutschland) GmbH, Eschborn, Germany
| | - P J Wensveen
- Faculty of Life and Environmental Sciences, University of Iceland, Askja, Sturlugata 7, 102 Reykjavik, Iceland
| | - P L Tyack
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, United Kingdom
| | - P H Kvadsheim
- Sensor and Surveillance Systems, Norwegian Defense Research Establishment (FFI), NO-3191 Horten, Norway
| | - F P A Lam
- Acoustics and Sonar, Netherlands Organization for Applied Scientific Research (TNO), P.O. Box 96864, The Hague 2509 JG, The Netherlands
| | - P J O Miller
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, United Kingdom
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6
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Pedersen MB, Tønnesen P, Malinka CE, Ladegaard M, Johnson M, Aguilar de Soto N, Madsen PT. Echolocation click parameters of short-finned pilot whales (Globicephala macrorhynchus) in the wild. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 149:1923. [PMID: 33765819 DOI: 10.1121/10.0003762] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
Short-finned pilot whales (Globicephala macrorhynchus) are large, deep-diving predators with diverse foraging strategies, but little is known about their echolocation. To quantify the source properties of short-finned pilot whale clicks, we made 15 deployments off the coast of Tenerife of a deep-water hydrophone array consisting of seven autonomous time-synced hydrophone recorders (SoundTraps), enabling acoustic localization and quantification of click source parameters. Of 8185 recorded pilot whale clicks, 47 were classified as being recorded on-axis, with a mean peak-to-peak source level (SL) of 181 ± 7 dB re 1 μPa, a centroid frequency of 40 ± 4 kHz, and a duration of 57 ± 23 μs. A fit to a piston model yielded an estimated half-power (-3 dB) beam width of 13.7° [95% confidence interval (CI) 13.2°-14.5°] and a mean directivity index (DI) of 22.6 dB (95% CI 22.5-22.9 dB). These measured SLs and DIs are surprisingly low for a deep-diving toothed whale, suggesting we sampled the short-finned pilot whales in a context with little need for operating a long-range biosonar. The substantial spectral overlap with beaked whale clicks emitted in similar deep-water habitats implies that pilot whale clicks may constitute a common source of false detections in beaked whale passive acoustic monitoring efforts.
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Affiliation(s)
- M B Pedersen
- Marine Bioacoustics Lab, Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
| | - P Tønnesen
- Marine Bioacoustics Lab, Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
| | - C E Malinka
- Marine Bioacoustics Lab, Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
| | - M Ladegaard
- Marine Bioacoustics Lab, Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
| | - M Johnson
- Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus C, Denmark
| | - N Aguilar de Soto
- Biodiversidad, Ecología Marina y Conservación (BIOECOMAC), University of La Laguna, 38206 La Laguna, Tenerife, Canary Islands, Spain
| | - P T Madsen
- Marine Bioacoustics Lab, Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
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7
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Lewanzik D, Goerlitz HR. Task-dependent vocal adjustments to optimize biosonar-based information acquisition. J Exp Biol 2021; 224:jeb234815. [PMID: 33234681 DOI: 10.1242/jeb.234815] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/13/2020] [Indexed: 01/09/2023]
Abstract
Animals need to acquire adequate and sufficient information to guide movements, yet information acquisition and processing are costly. Animals thus face a trade-off between gathering too little and too much information and, accordingly, actively adapt sensory input through motor control. Echolocating animals provide a unique opportunity to study the dynamics of adaptive sensing in naturally behaving animals, as every change in the outgoing echolocation signal directly affects information acquisition and the perception of the dynamic acoustic scene. Here, we investigated the flexibility with which bats dynamically adapt information acquisition depending on a task. We recorded the echolocation signals of wild-caught Western barbastelle bats (Barbastella barbastellus) while they were flying through an opening, drinking on the wing, landing on a wall and capturing prey. We show that the echolocation signal sequences during target approach differed in a task-dependent manner; bats started the target approach earlier and increased the information update rate more when the task became increasingly difficult, and bats also adjusted the dynamics of call duration shortening and peak frequency shifts accordingly. These task-specific differences existed from the onset of object approach, implying that bats plan their sensory-motor programme for object approach exclusively based on information received from search call echoes. We provide insight into how echolocating animals deal with the constraints they face when sequentially sampling the world through sound by adjusting acoustic information flow from slow to extremely fast in a highly dynamic manner. Our results further highlight the paramount importance of high behavioural flexibility for acquiring information.
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Affiliation(s)
- Daniel Lewanzik
- Acoustic and Functional Ecology, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, 82319 Seewiesen, Germany
| | - Holger R Goerlitz
- Acoustic and Functional Ecology, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, 82319 Seewiesen, Germany
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8
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Beedholm K, Malinka C, Ladegaard M, Madsen PT. Do echolocating toothed whales direct their acoustic gaze on- or off-target in a static detection task? THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 149:581. [PMID: 33514151 DOI: 10.1121/10.0003357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/28/2020] [Indexed: 06/12/2023]
Abstract
Echolocating mammals produce directional sound beams with high source levels to improve echo-to-noise ratios and reduce clutter. Recent studies have suggested that the differential spectral gradients of such narrow beams are exploited to facilitate target localization by pointing the beam slightly off targets to maximize the precision of angular position estimates [maximizing bearing Fisher information (FI)]. Here, we test the hypothesis that echolocating toothed whales focus their acoustic gaze askew during target detection to maximize spectral cues by investigating the acoustic gaze direction of two trained delphinids (Tursiops truncatus and Pseudorca crassidens) echolocating to detect an aluminum cylinder behind a hydrophone array in a go/no-go paradigm. The animals rarely placed their beam axis directly on the target, nor within the narrow range around the off-axis angle that maximizes FI. However, the target was, for each trial, ensonified within the swath of the half-power beam width, and hence we conclude that the animals solved the detection task using a strategy that seeks to render high echo-to-noise ratios rather than maximizing bearing FI. We posit that biosonar beam adjustment and acoustic gaze strategies are likely task-dependent and that maximizing bearing FI by pointing off-axis does not improve target detection performance.
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Affiliation(s)
- Kristian Beedholm
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
| | - Chloe Malinka
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
| | - Michael Ladegaard
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
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9
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Macaulay JDJ, Malinka CE, Gillespie D, Madsen PT. High resolution three-dimensional beam radiation pattern of harbour porpoise clicks with implications for passive acoustic monitoring. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:4175. [PMID: 32611133 DOI: 10.1121/10.0001376] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 05/13/2020] [Indexed: 06/11/2023]
Abstract
The source properties and radiation patterns of animal vocalisations define, along with propagation and noise conditions, the active space in which these vocalisations can be detected by conspecifics, predators, prey, and by passive acoustic monitoring (PAM). This study reports the 4π (360° horizontal and vertical) beam profile of a free-swimming, trained harbour porpoise measured using a 27-element hydrophone array. The forward echolocation beam is highly directional, as predicted by a piston model, and is consistent with previous measurements. However, at off-axis angles greater than ±30°, the beam attenuates more rapidly than the piston model and no side lobes are present. A diffuse back beam is also present with levels about -30 dB relative to the source level. In PAM, up to 50% of detections can be from portions of the beam profile with distorted click spectra, although this drops substantially for higher detection thresholds. Simulations of the probability of acoustically detecting a harbour porpoise show that a traditional piston model can underestimate the probability of detection compared to the actual three-dimensional radiation pattern documented here. This highlights the importance of empirical 4π measurements of beam profiles of toothed whales, both to improve understanding of toothed whale biology and to inform PAM.
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Affiliation(s)
- Jamie D J Macaulay
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of Saint Andrews, East Sands, Saint Andrews, Fife, KY16 9LB, United Kingdom
| | - Chloe E Malinka
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Douglas Gillespie
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of Saint Andrews, East Sands, Saint Andrews, Fife, KY16 9LB, United Kingdom
| | - Peter T Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
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10
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Burchardt LS, Knörnschild M. Comparison of methods for rhythm analysis of complex animals' acoustic signals. PLoS Comput Biol 2020; 16:e1007755. [PMID: 32267836 PMCID: PMC7141653 DOI: 10.1371/journal.pcbi.1007755] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/28/2020] [Indexed: 12/21/2022] Open
Abstract
Analyzing the rhythm of animals' acoustic signals is of interest to a growing number of researchers: evolutionary biologists want to disentangle how these structures evolved and what patterns can be found, and ecologists and conservation biologists aim to discriminate cryptic species on the basis of parameters of acoustic signals such as temporal structures. Temporal structures are also relevant for research on vocal production learning, a part of which is for the animal to learn a temporal structure. These structures, in other words, these rhythms, are the topic of this paper. How can they be investigated in a meaningful, comparable and universal way? Several approaches exist. Here we used five methods to compare their suitability and interpretability for different questions and datasets and test how they support the reproducibility of results and bypass biases. Three very different datasets with regards to recording situation, length and context were analyzed: two social vocalizations of Neotropical bats (multisyllabic, medium long isolation calls of Saccopteryx bilineata, and monosyllabic, very short isolation calls of Carollia perspicillata) and click trains of sperm whales, Physeter macrocephalus. Techniques to be compared included Fourier analysis with a newly developed goodness-of-fit value, a generate-and-test approach where data was overlaid with varying artificial beats, and the analysis of inter-onset-intervals and calculations of a normalized Pairwise Variability Index (nPVI). We discuss the advantages and disadvantages of the methods and we also show suggestions on how to best visualize rhythm analysis results. Furthermore, we developed a decision tree that will enable researchers to select a suitable and comparable method on the basis of their data.
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Affiliation(s)
- Lara S. Burchardt
- Museum für Naturkunde, Invalidenstraße, Berlin, Germany
- Animal Behavior Lab, Free University Berlin, Berlin, Germany
| | - Mirjam Knörnschild
- Museum für Naturkunde, Invalidenstraße, Berlin, Germany
- Animal Behavior Lab, Free University Berlin, Berlin, Germany
- Smithsonian Tropical Research Institute, Barro Colorado Island, Balboa, Ancón, Panamá
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11
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Jensen FH, Keller OA, Tyack PL, Visser F. Dynamic biosonar adjustment strategies in deep-diving Risso's dolphins driven partly by prey evasion. ACTA ACUST UNITED AC 2020; 223:jeb.216283. [PMID: 31822550 DOI: 10.1242/jeb.216283] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/02/2019] [Indexed: 11/20/2022]
Abstract
Toothed whales have evolved flexible biosonar systems to find, track and capture prey in diverse habitats. Delphinids, phocoenids and iniids adjust inter-click intervals and source levels gradually while approaching prey. In contrast, deep-diving beaked and sperm whales maintain relatively constant inter-click intervals and apparent output levels during the approach followed by a rapid transition into the foraging buzz, presumably to maintain a long-range acoustic scene in a multi-target environment. However, it remains unknown whether this rapid biosonar adjustment strategy is shared by delphinids foraging in deep waters. To test this, we investigated biosonar adjustments of a deep-diving delphinid, the Risso's dolphin (Grampus griseus). We analyzed inter-click interval and apparent output level adjustments recorded from sound recording tags to quantify in situ sensory adjustment during prey capture attempts. Risso's dolphins did not follow typical (20logR) biosonar adjustment patterns seen in shallow-water species, but instead maintained stable repetition rates and output levels up to the foraging buzz. Our results suggest that maintaining a long-range acoustic scene to exploit complex, multi-target prey layers is a common strategy amongst deep-diving toothed whales. Risso's dolphins transitioned rapidly into the foraging buzz just like beaked whales during most foraging attempts, but employed a more gradual biosonar adjustment in a subset (19%) of prey approaches. These were characterized by higher speeds and minimum specific acceleration, indicating higher prey capture efforts associated with evasive prey. Thus, tracking and capturing evasive prey using biosonar may require a more gradual switch between multi-target echolocation and single-target tracking.
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Affiliation(s)
- Frants H Jensen
- Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus C, Denmark .,Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Onno A Keller
- Department of Coastal Systems, Royal Netherlands Institute for Sea Research and Utrecht University, P.O. Box 59, 1790 AB Den Burg Texel, The Netherlands.,Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands.,Department of Animal Ecology, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Peter L Tyack
- Scottish Oceans Institute, School of Biology, University of St Andrews, East Sands, St Andrews KY16 8LB, UK
| | - Fleur Visser
- Department of Coastal Systems, Royal Netherlands Institute for Sea Research and Utrecht University, P.O. Box 59, 1790 AB Den Burg Texel, The Netherlands.,Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE Amsterdam, The Netherlands.,Kelp Marine Research, 1624CJ Hoorn, The Netherlands
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12
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Gong Z, Dong L, Caruso F, Lin M, Liu M, Dong J, Li S. Echolocation signals of free-ranging pantropical spotted dolphins (Stenella attenuata) in the South China Sea. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 145:3480. [PMID: 31255156 DOI: 10.1121/1.5111742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 05/28/2019] [Indexed: 06/09/2023]
Abstract
Echolocation signals of free-ranging pantropical spotted dolphins (Stenella attenuata) in the western Pacific Ocean have not been studied much. This paper aims to describe the characteristics of echolocation signals of S. attenuata in the northern South China Sea. A six-arm star array with 13 hydrophones was used and a total of 131 on-axis clicks were identified to analyze the acoustic features of the echolocation signals of dolphins. The mean center frequency was 89 ± 13 kHz, with mean peak-to-peak sound source levels of 190 ± 6 dB re: 1 μPa @ 1 m. The mean -3 dB bandwidth and root-mean-square bandwidth were 62 ± 15 kHz and 26 ± 3 kHz, respectively, with mean -10 dB duration of 18 ± 4 μs and root-mean-square duration of 6 ± 2 μs. The results showed that click parameters of S. attenuata in the northern South China Sea are different from those of clicks of the species in Hawaii waters. The differences in click parameters may be due to both behavioral context and/or environmental adaptation of S. attenuata in different habitats.
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Affiliation(s)
- Zining Gong
- Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
| | - Lijun Dong
- Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
| | - Francesco Caruso
- Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
| | - Mingli Lin
- Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
| | - Mingming Liu
- Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
| | - Jianchen Dong
- Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
| | - Songhai Li
- Sanya Key Laboratory of Marine Mammal and Marine Bioacoustics, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China
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13
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Smith AB, Pacini AF, Nachtigall PE, Laule GE, Aragones LV, Magno C, Suarez LJA. Transmission beam pattern and dynamics of a spinner dolphin (Stenella longirostris). THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 145:3595. [PMID: 31255135 DOI: 10.1121/1.5111347] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/24/2019] [Indexed: 06/09/2023]
Abstract
Toothed whales possess a sophisticated biosonar system by which ultrasonic clicks are projected in a highly directional transmission beam. Beam directivity is an important biosonar characteristic that reduces acoustic clutter and increases the acoustic detection range. This study measured click characteristics and the transmission beam pattern from a small odontocete, the spinner dolphin (Stenella longirostis). A formerly stranded individual was rehabilitated and trained to station underwater in front of a 16-element hydrophone array. On-axis clicks showed a mean duration of 20.1 μs, with mean peak and centroid frequencies of 58 and 64 kHz [standard deviation (s.d.) ±30 and ±12 kHz], respectively. Clicks were projected in an oval, vertically compressed beam, with mean vertical and horizontal beamwidths of 14.5° (s.d. ± 3.9) and 16.3° (s.d. ± 4.6), respectively. Directivity indices ranged from 14.9 to 27.4 dB, with a mean of 21.7 dB, although this likely represents a broader beam than what is normally produced by wild individuals. A click subset with characteristics more similar to those described for wild individuals exhibited a mean directivity index of 23.3 dB. Although one of the broadest transmission beams described for a dolphin, it is similar to other small bodied odontocetes.
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Affiliation(s)
- Adam B Smith
- Marine Mammal Research Program, Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, Hawaii 96744, USA
| | - Aude F Pacini
- Marine Mammal Research Program, Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, Hawaii 96744, USA
| | - Paul E Nachtigall
- Marine Mammal Research Program, Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, Hawaii 96744, USA
| | - Gail E Laule
- Ocean Adventure, Camayan Wharf, West Ilanin Forest, Subic Bay Freeport Zone, Philippines
| | - Lemnuel V Aragones
- Institute of Environmental Science and Meteorology, University of the Philippines, Diliman, Quezon City, Philippines
| | - Carlo Magno
- Ocean Adventure, Camayan Wharf, West Ilanin Forest, Subic Bay Freeport Zone, Philippines
| | - Leo J A Suarez
- Ocean Adventure, Camayan Wharf, West Ilanin Forest, Subic Bay Freeport Zone, Philippines
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14
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Ladegaard M, Mulsow J, Houser DS, Jensen FH, Johnson M, Madsen PT, Finneran JJ. Dolphin echolocation behaviour during active long-range target approaches. ACTA ACUST UNITED AC 2019; 222:jeb.189217. [PMID: 30478155 DOI: 10.1242/jeb.189217] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 11/22/2018] [Indexed: 11/20/2022]
Abstract
Echolocating toothed whales generally adjust click intensity and rate according to target range to ensure that echoes from targets of interest arrive before a subsequent click is produced, presumably facilitating range estimation from the delay between clicks and returning echoes. However, this click-echo-click paradigm for the dolphin biosonar is mostly based on experiments with stationary animals echolocating fixed targets at ranges below ∼120 m. Therefore, we trained two bottlenose dolphins instrumented with a sound recording tag to approach a target from ranges up to 400 m and either touch the target (subject TRO) or detect a target orientation change (subject SAY). We show that free-swimming dolphins dynamically increase interclick interval (ICI) out to target ranges of ∼100 m. TRO consistently kept ICIs above the two-way travel time (TWTT) for target ranges shorter than ∼100 m, whereas SAY switched between clicking at ICIs above and below the TWTT for target ranges down to ∼25 m. Source levels changed on average by 17log10(target range), but with considerable variation for individual slopes (4.1 standard deviations for by-trial random effects), demonstrating that dolphins do not adopt a fixed automatic gain control matched to target range. At target ranges exceeding ∼100 m, both dolphins frequently switched to click packet production in which interpacket intervals exceeded the TWTT, but ICIs were shorter than the TWTT. We conclude that the click-echo-click paradigm is not a fixed echolocation strategy in dolphins, and we demonstrate the first use of click packets for free-swimming dolphins when solving an echolocation task.
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Affiliation(s)
- Michael Ladegaard
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
| | - Jason Mulsow
- National Marine Mammal Foundation, 2240 Shelter Island Drive, Suite 200, San Diego, CA 92106, USA
| | - Dorian S Houser
- National Marine Mammal Foundation, 2240 Shelter Island Drive, Suite 200, San Diego, CA 92106, USA
| | | | - Mark Johnson
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark.,Sea Mammal Research Unit, St Andrews KY16 8LB, UK
| | - Peter Teglberg Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus, Denmark
| | - James J Finneran
- United States Navy Marine Mammal Program, Space and Naval Warfare Systems Center Pacific, Code 71510, 53560 Hull Street, San Diego, CA 92152, USA
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15
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Ladegaard M, Madsen PT. Context-dependent biosonar adjustments during active target approaches in echolocating harbour porpoises. J Exp Biol 2019; 222:jeb.206169. [DOI: 10.1242/jeb.206169] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 07/16/2019] [Indexed: 11/20/2022]
Abstract
Echolocating mammals generally target individual prey items by transitioning through the biosonar phases of search (slow-rate, high-amplitude outputs), approach (gradually increasing rate and decreasing output amplitude) and buzzing (high-rate, low-amplitude outputs). The range to the main target of interest is often considered the key or sole driver of such biosonar adjustments of acoustic gaze. However, the actively-generated auditory scene of an echolocator is invariably comprised of a large number of other reflectors and noise sources that likely also impact the biosonar strategies and source parameters implemented by an echolocating animal in time and space. In toothed whales the importance of context on biosonar adjustments is largely unknown. To address this, we trained two harbour porpoises to actively approach the same sound recording target over the same approach distance in two highly different environments; a PVC-lined pool and a semi-natural net pen in a harbour, while blind-folded and wearing a sound recording tag (DTAG-4). We show that the approaching porpoises used considerably shorter interclick intervals (ICI) in the pool than in the net pen, except during the buzz phase where slightly longer ICIs were used in the pool. We further show that average click source levels were 4-7 dB higher in the net pen. Because of the very low-level in-band ambient noise in both environments, we posit that the porpoises adapted their echolocation strategy to the different reverberation levels between the two settings. We demonstrate that harbour porpoises use different echolocation strategies and biosonar parameters in two different environments for solving an otherwise identical target approach task and thus highlight that biosonar adjustments are both range and context-dependent.
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Affiliation(s)
- Michael Ladegaard
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
| | - Peter Teglberg Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
- Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus, Denmark
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16
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Jensen FH, Johnson M, Ladegaard M, Wisniewska DM, Madsen PT. Narrow Acoustic Field of View Drives Frequency Scaling in Toothed Whale Biosonar. Curr Biol 2018; 28:3878-3885.e3. [DOI: 10.1016/j.cub.2018.10.037] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/12/2018] [Accepted: 10/12/2018] [Indexed: 11/27/2022]
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17
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de Freitas M, Smith JN, Jensen FH, Beedholm K, Madsen PT. Echolocation click source parameters of Australian snubfin dolphins (Orcaella heinsohni). THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 143:2564. [PMID: 29716291 DOI: 10.1121/1.5034174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The Australian snubfin dolphin (Orcaella heinsohni) is endemic to Australian waters, yet little is known about its abundance and habitat use. To investigate the feasibility of Passive Acoustic Monitoring for snubfin dolphins, biosonar clicks were recorded in Cygnet Bay, Australia, using a four-element hydrophone array. Clicks had a mean source level of 200 ± 5 dB re 1 μPa pp, transmission directivity index of 24 dB, mean centroid frequency of 98 ± 9 kHz, and a root-mean-square bandwidth of 31 ± 3 kHz. Such properties lend themselves to passive acoustic monitoring, but are comparable to similarly-sized delphinids, thus requiring additional cues to discriminate between snubfins and sympatric species.
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Affiliation(s)
- Mafalda de Freitas
- Department of Bioscience, Aarhus University, Building 1131, C.F. Moellers Alle 3, DK-8000 Aarhus C, Denmark
| | - Joshua N Smith
- Murdoch University Cetacean Research Unit, School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, Western Australia, 6150, Australia
| | - Frants H Jensen
- Aarhus Institute of Advanced Studies, Aarhus University, Høegh-Guldbergs Gade 6B, 8000 Aarhus C, Denmark
| | - Kristian Beedholm
- Department of Bioscience, Aarhus University, Building 1131, C.F. Moellers Alle 3, DK-8000 Aarhus C, Denmark
| | - Peter T Madsen
- Department of Bioscience, Aarhus University, Building 1131, C.F. Moellers Alle 3, DK-8000 Aarhus C, Denmark
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18
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Jakobsen L, Hallam J, Moss CF, Hedenström A. Directionality of nose-emitted echolocation calls from bats without a nose leaf ( Plecotus auritus). ACTA ACUST UNITED AC 2018; 221:jeb.171926. [PMID: 29222128 DOI: 10.1242/jeb.171926] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 12/06/2017] [Indexed: 11/20/2022]
Abstract
All echolocating bats and whales measured to date emit a directional bio-sonar beam that affords them a number of advantages over an omni-directional beam, i.e. reduced clutter, increased source level and inherent directional information. In this study, we investigated the importance of directional sound emission for navigation through echolocation by measuring the sonar beam of brown long-eared bats, Plecotus auritusPlecotus auritus emits sound through the nostrils but has no external appendages to readily facilitate a directional sound emission as found in most nose emitters. The study shows that P. auritus, despite lacking an external focusing apparatus, emits a directional echolocation beam (directivity index=13 dB) and that the beam is more directional vertically (-6 dB angle at 22 deg) than horizontally (-6 dB angle at 35 deg). Using a simple numerical model, we found that the recorded emission pattern is achievable if P. auritus emits sound through the nostrils as well as the mouth. The study thus supports the hypothesis that a directional echolocation beam is important for perception through echolocation and we propose that animals with similarly non-directional emitter characteristics may facilitate a directional sound emission by emitting sound through both the nostrils and the mouth.
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Affiliation(s)
- Lasse Jakobsen
- Centre for BioRobotics, Department of Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - John Hallam
- Centre for BioRobotics, Maersk McKinney Moller Institute, University of Southern Denmark, DK-5230 Odense M, Denmark
| | | | - Anders Hedenström
- Centre for Animal Movement Research, Department of Biology, Lund University, 223 62 Lund, Sweden
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