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Casey C, Fregosi S, Oswald JN, Janik VM, Visser F, Southall B. Common dolphin whistle responses to experimental mid-frequency sonar. PLoS One 2024; 19:e0302035. [PMID: 38669257 PMCID: PMC11051594 DOI: 10.1371/journal.pone.0302035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
Oceanic delphinids that occur in and around Navy operational areas are regularly exposed to intense military sonar broadcast within the frequency range of their hearing. However, empirically measuring the impact of sonar on the behavior of highly social, free-ranging dolphins is challenging. Additionally, baseline variability or the frequency of vocal state-switching among social oceanic dolphins during undisturbed conditions is lacking, making it difficult to attribute changes in vocal behavior to anthropogenic disturbance. Using a network of drifting acoustic buoys in controlled exposure experiments, we investigated the effects of mid-frequency (3-4 kHz) active sonar (MFAS) on whistle production in short-beaked (Delphinus delphis delphis) and long-beaked common dolphins (Delphinus delphis bairdii) in southern California. Given the complexity of acoustic behavior exhibited by these group-living animals, we conducted our response analysis over varying temporal windows (10 min- 5 s) to describe both longer-term and instantaneous changes in sound production. We found that common dolphins exhibited acute and pronounced changes in whistle rate in the 5 s following exposure to simulated Navy MFAS. This response was sustained throughout sequential MFAS exposures within experiments simulating operational conditions, suggesting that dolphins may not habituate to this disturbance. These results indicate that common dolphins exhibit brief yet clearly detectable acoustic responses to MFAS. They also highlight how variable temporal analysis windows-tuned to key aspects of baseline vocal behavior as well as experimental parameters related to MFAS exposure-enable the detection of behavioral responses. We suggest future work with oceanic delphinids explore baseline vocal rates a-priori and use information on the rate of change in vocal behavior to inform the analysis time window over which behavioral responses are measured.
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Affiliation(s)
- Caroline Casey
- Southall Environmental Associates, Inc., Aptos, California, United States of America
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Selene Fregosi
- Southall Environmental Associates, Inc., Aptos, California, United States of America
| | - Julie N. Oswald
- Scottish Oceans Institute, Sea Mammal Research Unit, School of Biology, University of St. Andrews, St. Andrews, United Kingdom
| | - Vincent M. Janik
- Scottish Oceans Institute, Sea Mammal Research Unit, School of Biology, University of St. Andrews, St. Andrews, United Kingdom
| | - Fleur Visser
- Kelp Marine Research, Hoorn, The Netherlands
- Department of Coastal Systems, Royal Netherlands Institute for Sea Research, Den Burg, Texel, The Netherlands
| | - Brandon Southall
- Southall Environmental Associates, Inc., Aptos, California, United States of America
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
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Smeele SQ, Tyndel SA, Aplin LM, McElreath MB. Multilevel Bayesian analysis of monk parakeet contact calls shows dialects between European cities. Behav Ecol 2024; 35:arad093. [PMID: 38193012 PMCID: PMC10773303 DOI: 10.1093/beheco/arad093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 09/21/2023] [Accepted: 10/16/2023] [Indexed: 01/10/2024] Open
Abstract
Geographic differences in vocalizations provide strong evidence for animal culture, with patterns likely arising from generations of social learning and transmission. Most studies on the evolution of avian vocal variation have predominantly focused on fixed repertoire, territorial song in passerine birds. The study of vocal communication in open-ended learners and in contexts where vocalizations serve other functions is therefore necessary for a more comprehensive understanding of vocal dialect evolution. Parrots are open-ended vocal production learners that use vocalizations for social contact and coordination. Geographic variation in parrot vocalizations typically take the form of either distinct regional variations known as dialects or graded variation based on geographic distance known as clinal variation. In this study, we recorded monk parakeets (Myiopsitta monachus) across multiple spatial scales (i.e., parks and cities) in their European invasive range. We then compared calls using a multilevel Bayesian model and sensitivity analysis, with this novel approach allowing us to explicitly compare vocalizations at multiple spatial scales. We found support for founder effects and/or cultural drift at the city level, consistent with passive cultural processes leading to large-scale dialect differences. We did not find a strong signal for dialect or clinal differences between parks within cities, suggesting that birds did not actively converge on a group level signal, as expected under the group membership hypothesis. We demonstrate the robustness of our findings and offer an explanation that unifies the results of prior monk parakeet vocalization studies.
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Affiliation(s)
- Simeon Q Smeele
- Cognitive & Cultural Ecology Research Group, Max Planck Institute of Animal Behavior, Am Obstberg 1, 78315 Radolfzell, Germany
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Deutscher Pl. 6, 04103 Leipzig, Germany
- Ecoscience, Aarhus University, Nordre Ringgade 1, 8000 Aarhus C, Denmark
| | - Stephen A Tyndel
- Cognitive & Cultural Ecology Research Group, Max Planck Institute of Animal Behavior, Am Obstberg 1, 78315 Radolfzell, Germany
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - Lucy M Aplin
- Cognitive & Cultural Ecology Research Group, Max Planck Institute of Animal Behavior, Am Obstberg 1, 78315 Radolfzell, Germany
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton ACT 2601, Australia
- Department of Evolutionary Biology and Environmental Science, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Mary Brooke McElreath
- Cognitive & Cultural Ecology Research Group, Max Planck Institute of Animal Behavior, Am Obstberg 1, 78315 Radolfzell, Germany
- Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Deutscher Pl. 6, 04103 Leipzig, Germany
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Rege-Colt M, Oswald JN, De Weerdt J, Palacios-Alfaro JD, Austin M, Gagne E, Morán Villatoro JM, Sahley CT, Alvarado-Guerra G, May-Collado LJ. Whistle repertoire and structure reflect ecotype distinction of pantropical spotted dolphins in the Eastern Tropical Pacific. Sci Rep 2023; 13:13449. [PMID: 37596372 PMCID: PMC10439233 DOI: 10.1038/s41598-023-40691-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 08/16/2023] [Indexed: 08/20/2023] Open
Abstract
The pantropical spotted dolphin in the Eastern Tropical Pacific (ETP) is found in two genetically and phenotypically diverged ecotypes, coastal and offshore. These habitats have distinct acoustic characteristics, which can lead to the evolution of distinct acoustic communication. Whistles are sounds widely used by dolphins to mediate species and individual recognition and social interactions. Here, we study the whistle acoustic structure and repertoire diversity of offshore and coastal pantropical spotted dolphins. Our results show that there is significantly more within- and across-group variation in whistle fundamental frequency between ecotypes than between offshore groups and between coastal groups. A Random Forest classification analysis performed with an accuracy of 83.99% and identified duration, peak and minimum frequency as the most informative variables for distinguishing between ecotypes. Overall, coastal spotted dolphins produced significantly shorter whistles that were significantly lower in frequency (peak, minimum and maximum, and start and end) than offshore dolphins. Ecotypes produced whistle repertoires that were similar in diversity, but different in contour composition, with the coastal ecotype producing more upsweep whistles than offshore dolphins. The results of this study suggest that acoustic adaptations to coastal and offshore environments could be important contributors to intraspecific variation of dolphin whistle repertoires.
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Affiliation(s)
| | - Julie N Oswald
- Scottish Oceans Institute, Sea Mammal Research Unit, University of St. Andrews, St. Andrews, KY168LB, UK
| | - Joelle De Weerdt
- Association ELI-S, Education, Liberté, Indépendance - Scientifique, Allée de Verdalle 39, 33470, Gujan-Mestras, France
- Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium
| | | | - Maia Austin
- Biology Department, University of Vermont, Burlington, VT, USA
| | - Emma Gagne
- Biology Department, University of Vermont, Burlington, VT, USA
| | | | | | - Gilma Alvarado-Guerra
- Instituto para el Crecimiento Sostenible de la Empresa (ICSEM), C/Hogar Padre Vito Guarato, B1, San Salvador, El Salvador
| | - Laura J May-Collado
- Biology Department, University of Vermont, Burlington, VT, USA.
- Smithsonian Tropical Research Institute, Panama, Panama.
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Carlón-Beltrán Ó, Viloria-Gómora L, Urbán R. J, Martínez-Aguilar S, Antichi S. Whistle characterization of long-beaked common dolphin ( Delphinus delphis bairdii) in La Paz Bay, Gulf of California. PeerJ 2023; 11:e15687. [PMID: 37483973 PMCID: PMC10362854 DOI: 10.7717/peerj.15687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 06/14/2023] [Indexed: 07/25/2023] Open
Abstract
Long-beaked common dolphin (Delphinus delphis bairdii) distribution is limited to the Eastern North Pacific Ocean. Its whistle repertoire is poorly investigated, with no studies in the Gulf of California. The aim of the present study is to characterize the whistles of this species and compare their parameters with different populations. Acoustic monitoring was conducted in La Paz Bay, Gulf of California. Recordings were inspected in spectrogram view in Raven Pro, selecting good quality whistles (n = 270). In the software Luscinia, contours were manually traced to obtain whistle frequencies and duration. Number of steps, inflection points and contour type were visually determined. We calculated the descriptive statistics of the selected whistle parameters and we compared the results with a dolphins population from the Eastern Pacific Ocean. Permutational multivariate analysis of variance (PERMANOVA) was performed to test the intraspecific variation of the whistle parameters among groups. In the present study the mean values (±SD) of the whistle parameters were: maximum frequency = 14.13 ± 3.71 kHz, minimum frequency = 8.44 ± 2.58 kHz and duration = 0.44 ± 0.31 s. Whistles with the upsweep contour were the most common ones (34.44%). The coefficient of variation (CV) values for modulation parameters were high (>100%), in accordance with other studies on dolphins. Whistle parameters showed significant differences among groups. Finally, ending and maximum frequencies, duration and inflection points of the whistles recorded in the present study were lower compared with the parameters of the long-beaked common dolphins from the Eastern Pacific Ocean. This study provides the first whistle characterization of long-beaked common dolphin from the Gulf of California and it will help future passive acoustic monitoring applications in the study area.
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Affiliation(s)
- Óscar Carlón-Beltrán
- Department of Marine and Coastal Sciences, Autonomous University of Baja California Sur, La Paz, Baja California Sur, Mexico
| | - Lorena Viloria-Gómora
- Department of Marine and Coastal Sciences, Autonomous University of Baja California Sur, La Paz, Baja California Sur, Mexico
| | - Jorge Urbán R.
- Department of Marine and Coastal Sciences, Autonomous University of Baja California Sur, La Paz, Baja California Sur, Mexico
| | - Sergio Martínez-Aguilar
- Department of Marine and Coastal Sciences, Autonomous University of Baja California Sur, La Paz, Baja California Sur, Mexico
| | - Simone Antichi
- Department of Marine and Coastal Sciences, Autonomous University of Baja California Sur, La Paz, Baja California Sur, Mexico
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First Description of the Underwater Sounds in the Mediterranean Monk Seal Monachus monachus in Greece: Towards Establishing a Vocal Repertoire. Animals (Basel) 2023; 13:ani13061048. [PMID: 36978589 PMCID: PMC10044229 DOI: 10.3390/ani13061048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/07/2023] [Accepted: 03/08/2023] [Indexed: 03/16/2023] Open
Abstract
The Mediterranean monk seal Monachus monachus is one of the most endangered pinnipeds in the world, and is classified as “Endangered” by the International Union for the Conservation of Nature. Any additional knowledge about the species is invaluable to its effective conservation. In the present study, we deployed an autonomous underwater recorder in an important reproductive area of the Mediterranean monk seal in Greece to describe its underwater vocal repertoire. Over the 330 h of continuous recordings, 9231 vocalizations were labelled as potentially produced by Mediterranean monk seals, and 1694 good quality calls were analyzed. We defined 18 call types divided into three main call categories: harmonic, noisy, and pulsative calls. We also described the soundscape in which this endangered species lives and found that human activities around the two main pupping caves had a strong impact on the sonic environment of these seals: the noise level produced by boat traffic was high, and occurred on an hourly (25 to 50 min/hour) and daily basis (10.8 to 16.9 h/day). Such high levels of noise might not only impair the communication of the species, but also impact its survival, as chronic noise can induce physiological stress.
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Rand ZR, Wood JD, Oswald JN. Effects of duty cycles on passive acoustic monitoring of southern resident killer whale (Orcinus orca) occurrence and behavior. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 151:1651. [PMID: 35364953 DOI: 10.1121/10.0009752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 02/13/2022] [Indexed: 06/14/2023]
Abstract
Long-term passive acoustic monitoring of cetaceans is frequently limited by the data storage capacity and battery life of the recording system. Duty cycles are a mechanism for subsampling during the recording process that facilitates long-term passive acoustic studies. While duty cycles are often used, there has been little investigation on the impact that this approach has on the ability to answer questions about a species' behavior and occurrence. In this study, the effects of duty cycling on the acoustic detection of southern resident killer whales (SRKW) (Orcinus orca) were investigated. Continuous acoustic data were subsampled to create 288 subsampled datasets with cycle lengths from 5 to 180 min and listening proportions from 1% to 67%. Duty cycles had little effect on the detection of the daily presence of SRKW, especially when using cycle lengths of less than an hour. However, cycle lengths of 15-30 min and listening proportions of at least 33% were required to accurately calculate durations of acoustic bouts and identify those bouts to ecotype. These results show that the optimal duty cycle depends on the scale of the research question and provide a framework for quantitative analysis of duty cycles for other marine species.
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Affiliation(s)
- Zoe R Rand
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, KY16 8LB, United Kingdom
| | - Jason D Wood
- SMRU Consulting, Friday Harbor, Washington 98250, USA
| | - Julie N Oswald
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, KY16 8LB, United Kingdom
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Durban JW, Southall BL, Calambokidis J, Casey C, Fearnbach H, Joyce TW, Fahlbusch JA, Oudejans MG, Fregosi S, Friedlaender AS, Kellar NM, Visser F. Integrating remote sensing methods during controlled exposure experiments to quantify group responses of dolphins to navy sonar. MARINE POLLUTION BULLETIN 2022; 174:113194. [PMID: 34902768 DOI: 10.1016/j.marpolbul.2021.113194] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 11/21/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
Human noise can be harmful to sound-centric marine mammals. Significant research has focused on characterizing behavioral responses of protected cetacean species to navy mid-frequency active sonar (MFAS). Controlled exposure experiments (CEE) using animal-borne tags have proved valuable, but smaller dolphins are not amenable to tagging and groups of interacting individuals are more relevant behavioral units for these social species. To fill key data gaps on group responses of social delphinids that are exposed to navy MFAS in large numbers, we describe novel approaches for the coordinated collection and integrated analysis of multiple remotely-sensed datasets during CEEs. This involves real-time coordination of a sonar source, shore-based group tracking, aerial photogrammetry to measure fine-scale movements and passive acoustics to quantify vocal activity. Using an example CEE involving long-beaked common dolphins (Delphinus delphis bairdii), we demonstrate how resultant quantitative metrics can be used to estimate behavioral changes and noise exposure-response relationships.
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Affiliation(s)
- J W Durban
- Southall Environmental Associates, Inc., 9099 Soquel Drive, Aptos, CA 95003, USA; Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, 8901 La Jolla Shores Drive, La Jolla, CA 92037, USA.
| | - B L Southall
- Southall Environmental Associates, Inc., 9099 Soquel Drive, Aptos, CA 95003, USA; Institute of Marine Sciences, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA 95060, USA
| | - J Calambokidis
- Cascadia Research Collective, 218 1/2 W 4th Ave., Olympia, WA 98501, USA
| | - C Casey
- Southall Environmental Associates, Inc., 9099 Soquel Drive, Aptos, CA 95003, USA; Institute of Marine Sciences, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA 95060, USA
| | - H Fearnbach
- SR3 SeaLife Response, Rehabilitation and Research, 2003 S. 216th St. #98811, Des Moines, WA 98198, USA
| | - T W Joyce
- Environmental Assessment Services, 350 Hills St., Suite 112, Richland, WA 99354, USA
| | - J A Fahlbusch
- Cascadia Research Collective, 218 1/2 W 4th Ave., Olympia, WA 98501, USA; Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - M G Oudejans
- Kelp Marine Research, 1624 CJ Hoorn, the Netherlands
| | - S Fregosi
- Southall Environmental Associates, Inc., 9099 Soquel Drive, Aptos, CA 95003, USA
| | - A S Friedlaender
- Southall Environmental Associates, Inc., 9099 Soquel Drive, Aptos, CA 95003, USA; Institute of Marine Sciences, University of California Santa Cruz, 115 McAllister Way, Santa Cruz, CA 95060, USA
| | - N M Kellar
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, 8901 La Jolla Shores Drive, La Jolla, CA 92037, USA
| | - F Visser
- Kelp Marine Research, 1624 CJ Hoorn, the Netherlands; Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, 1090 GE Amsterdam, the Netherlands; Department of Coastal Systems, Royal Netherlands Institute for Sea Research, P.O. Box 59, 1790 AB Den Burg, Texel, the Netherlands
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Vernes SC, Janik VM, Fitch WT, Slater PJB. Vocal learning in animals and humans. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200234. [PMID: 34482718 PMCID: PMC8422595 DOI: 10.1098/rstb.2020.0234] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Sonja C Vernes
- School of Biology, The University of St Andrews, St Andrews, UK.,Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Vincent M Janik
- School of Biology, The University of St Andrews, St Andrews, UK
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Oswald JN, Walmsley SF, Casey C, Fregosi S, Southall B, Janik VM. Species information in whistle frequency modulation patterns of common dolphins. Philos Trans R Soc Lond B Biol Sci 2021; 376:20210046. [PMID: 34482716 PMCID: PMC8419585 DOI: 10.1098/rstb.2021.0046] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2021] [Indexed: 12/14/2022] Open
Abstract
The most flexible communication systems are those of open-ended vocal learners that can acquire new signals throughout their lifetimes. While acoustic signals carry information in general voice features that affect all of an individual's vocalizations, vocal learners can also introduce novel call types to their repertoires. Delphinids are known for using such learned call types in individual recognition, but their role in other contexts is less clear. We investigated the whistles of two closely related, sympatric common dolphin species, Delphinus delphis and Delphinus bairdii, to evaluate species differences in whistle contours. Acoustic recordings of single-species groups were obtained from the Southern California Bight. We used an unsupervised neural network to categorize whistles and compared the resulting whistle types between species. Of the whistle types recorded in more than one encounter, 169 were shared between species and 60 were species-specific (32 D. delphis types, 28 D. bairdii types). Delphinus delphis used 15 whistle types with an oscillatory frequency contour while only one such type was found in D. bairdii. Given the role of vocal learning in delphinid vocalizations, we argue that these differences in whistle production are probably culturally driven and could help facilitate species recognition between Delphinus species. This article is part of the theme issue 'Vocal learning in animals and humans'.
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Affiliation(s)
- Julie N. Oswald
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife KY16 8LB, UK
| | - Sam F. Walmsley
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife KY16 8LB, UK
| | - Caroline Casey
- Southall Environmental Associates, 9099 Soquel Drive, Suite 8, Aptos, CA 95003, USA
| | - Selene Fregosi
- Southall Environmental Associates, 9099 Soquel Drive, Suite 8, Aptos, CA 95003, USA
| | - Brandon Southall
- Southall Environmental Associates, 9099 Soquel Drive, Suite 8, Aptos, CA 95003, USA
- Long Marine Laboratory, Institute of Marine Sciences, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Vincent M. Janik
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife KY16 8LB, UK
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