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Abildtrup Nielsen N, Dawson SM, Torres Ortiz S, Wahlberg M, Martin MJ. Hector's dolphins (Cephalorhynchus hectori) produce both narrowband high-frequency and broadband acoustic signals. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2024; 155:1437-1450. [PMID: 38364047 DOI: 10.1121/10.0024820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 01/25/2024] [Indexed: 02/18/2024]
Abstract
Odontocetes produce clicks for echolocation and communication. Most odontocetes are thought to produce either broadband (BB) or narrowband high-frequency (NBHF) clicks. Here, we show that the click repertoire of Hector's dolphin (Cephalorhynchus hectori) comprises highly stereotypical NBHF clicks and far more variable broadband clicks, with some that are intermediate between these two categories. Both NBHF and broadband clicks were made in trains, buzzes, and burst-pulses. Most clicks within click trains were typical NBHF clicks, which had a median centroid frequency of 130.3 kHz (median -10 dB bandwidth = 29.8 kHz). Some, however, while having only marginally lower centroid frequency (median = 123.8 kHz), had significant energy below 100 kHz and approximately double the bandwidth (median -10 dB bandwidth = 69.8 kHz); we refer to these as broadband. Broadband clicks in buzzes and burst-pulses had lower median centroid frequencies (120.7 and 121.8 kHz, respectively) compared to NBHF buzzes and burst-pulses (129.5 and 130.3 kHz, respectively). Source levels of NBHF clicks, estimated by using a drone to measure ranges from a single hydrophone and by computing time-of-arrival differences at a vertical hydrophone array, ranged from 116 to 171 dB re 1 μPa at 1 m, whereas source levels of broadband clicks, obtained from array data only, ranged from 138 to 184 dB re 1 μPa at 1 m. Our findings challenge the grouping of toothed whales as either NBHF or broadband species.
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Affiliation(s)
- Nicoline Abildtrup Nielsen
- Marine Biological Research Center, Department of Biology, University of Southern Denmark, 5300 Kerteminde, Denmark
| | - Stephen M Dawson
- Department of Marine Science, University of Otago, Dunedin 9054, New Zealand
| | - Sara Torres Ortiz
- Marine Biological Research Center, Department of Biology, University of Southern Denmark, 5300 Kerteminde, Denmark
| | - Magnus Wahlberg
- Marine Biological Research Center, Department of Biology, University of Southern Denmark, 5300 Kerteminde, Denmark
| | - Morgan J Martin
- Center for Marine Acoustics, Bureau of Ocean Energy Management, Sterling, Virginia 20166, USA
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2
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Patris J, Malige F, Hamame M, Glotin H, Barchasz V, Gies V, Marzetti S, Buchan S. Medium-term acoustic monitoring of small cetaceans in Patagonia, Chile. PeerJ 2023; 11:e15292. [PMID: 37334123 PMCID: PMC10276556 DOI: 10.7717/peerj.15292] [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: 01/06/2022] [Accepted: 04/04/2023] [Indexed: 06/20/2023] Open
Abstract
Coastal dolphins and porpoises such as the Chilean dolphin (Cephalorhynchus eutropia), the Peale's dolphin (Lagenorhynchus australis), and the Burmeister's porpoise (Phocoena spinipinnis) inhabit the remote areas of Chilean Patagonia. Human development is growing fast in these parts and may constitute a serious threat to such poorly known species. It is thus urgent to develop new tools to try and study these cryptic species and find out more about their behavior, population levels, and habits. These odontocetes emit narrow-band high-frequency (NBHF) clicks and efforts have been made to characterize precisely their acoustic production. Passive acoustic monitoring is a common way to study these animals. Nevertheless, as the signal frequency is usually higher than 100 kHz, storage problems are acute and do not allow for long-term monitoring. The solutions for recording NBHF clicks are usually twofold: either short duration, opportunistic recording from a small boat in presence of the animals (short-term monitoring) or long-term monitoring using devices including a click detector and registering events rather than sound. We suggest, as another possibility, medium-term monitoring, arguing that today's devices have reached a level of performance allowing for a few days of continual recording even at these extremely high frequencies and in difficult conditions, combined with a long-term click detector. As an example, during 2021, we performed a quasi-continuous recording for one week with the Qualilife High-Blue recorder anchored in a fjord near Puerto Cisnes, Region de Aysen, Chile. We detected more than 13,000 clicks, grouped in 22 periods of passing animals. Our detected clicks are quite similar to precedent results but, due to the large number of clicks recorded, we find a larger variability of parameters. Several rapid sequences of clicks (buzz) were found in the recordings and their features are consistent with previous studies: on average they have a larger bandwidth and a lower peak frequency than the usual clicks. We also installed in the same place a click detector (C-POD) and the two devices compare well and show the same number and duration of periods of animals presence. Passages of odontocetes were happening on average each three hours. We thus confirm the high site fidelity for the species of dolphins emitting NBHF clicks present in this zone. Finally, we confirm that the combined use of recording and detection devices is probably a good alternative to study these poorly known species in remote areas.
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Affiliation(s)
| | - Franck Malige
- Laboratoire Informatique et Systèmes (LIS), CNRS UMR 7020, Toulon, France
| | - Madeleine Hamame
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Coyhaique, Chile
| | - Hervé Glotin
- Laboratoire Informatique et Systèmes (LIS), CNRS UMR 7020, Toulon, France
- Scientific Microsystems for Internet of Things (SMIoT), Université de Toulon et du Var, Toulon, France
| | - Valentin Barchasz
- Scientific Microsystems for Internet of Things (SMIoT), Université de Toulon et du Var, Toulon, France
| | - Valentin Gies
- Scientific Microsystems for Internet of Things (SMIoT), Université de Toulon et du Var, Toulon, France
- Institut Matériaux Microélectronique Nanosciences de Provence (IM2NP), CNRS UMR 7334, Toulon, France
| | - Sebastian Marzetti
- Scientific Microsystems for Internet of Things (SMIoT), Université de Toulon et du Var, Toulon, France
- Institut Matériaux Microélectronique Nanosciences de Provence (IM2NP), CNRS UMR 7334, Toulon, France
| | - Susannah Buchan
- Center for Oceanographic Research COPAS COASTAL, Universidad de Concepción, Concepción, Chile
- Departamento de Oceanografía, Universidad de Concepción, Concepción, Chile
- Centro de Estudios Avanzado en Zonas Aridas (CEAZA), Coquimbo, Chile
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3
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Communication sounds produced by captive narrow-ridged finless porpoises (Neophocaena asiaeorientalis). J ETHOL 2022. [DOI: 10.1007/s10164-022-00755-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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4
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Underwater Chatter for the Win: A First Assessment of Underwater Soundscapes in Two Bays along the Eastern Cape Coast of South Africa. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2022. [DOI: 10.3390/jmse10060746] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In 2014, the South African government launched ‘Operation Phakisa’ under which port developments play a significant role in supporting ocean economic growth. These developments will likely increase vessel traffic to and from South African ports, making it imperative to monitor for changes in underwater sound budgets with potential negative effects on marine life. However, no soundscape studies have been conducted around South Africa, resulting in an absence of baseline measurements. This study provides a first description of the underwater soundscape in St. Francis Bay and Algoa Bay, Eastern Cape. Soundscape measurements identified major soundscape contributors, temporal patterns in broadband sound levels, and underlying environmental drivers. Applicability of modelled vessel noise and wind noise maps to predict large-scale spatial variation in sound budgets was assessed. Our study shows that sounds from biological sources and wind dominated at all recording sites, with fish choruses driving temporal patterns as a function of time of year and position of the sun. Sound from vessels was present at all sites but most notable in long-term spectral levels measured in Algoa Bay. Sound propagation models predicted a further increase in the contribution of vessel noise towards shipping lanes and east Algoa Bay. Our study provides a building block to monitor for shifts in sound budgets and temporal patterns in these two bays under a developing ocean economy. Furthermore, our study raises concerns that vessel noise is likely a significant contributor in shallow waters elsewhere along the South African coast where vessel density is known to be higher (i.e., Durban and Cape Town).
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Zeh JM, Dombroski JRG, Parks SE. Preferred shallow-water nursery sites provide acoustic crypsis to southern right whale mother-calf pairs. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220241. [PMID: 35620006 PMCID: PMC9115009 DOI: 10.1098/rsos.220241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 04/28/2022] [Indexed: 05/03/2023]
Abstract
Adaptations to sound production behaviour can reduce the detectability of animal signals by eavesdroppers in a phenomenon known as acoustic crypsis. We propose that acoustic crypsis can include selection of locations that affect how sound transmits through the environment: habitats with poor acoustic propagation can minimize the range of detectability of animal signals. We investigated the potential for the preferred habitats of southern right whales to confer acoustic crypsis. We modelled acoustic propagation and range of detection of calls from southern right whales in the shallow, sandy, near shore waters where mothers and calves aggregate during the calving season. At three nursery sites across three continents in the southern hemisphere, results showed that the depth at which right whales are most commonly sighted has the most limited acoustic detection range for their calls. Thus, these habitats allow mother-calf pairs to remain acoustically cryptic from potential eavesdroppers, both predators and conspecifics, when their calves are the most vulnerable. Our results provide preliminary evidence that, in addition to other behavioural strategies, the use of habitats with poor acoustic propagation can contribute to acoustic crypsis. This adaptation may be a widespread and underappreciated mechanism for avoidance of eavesdroppers.
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Affiliation(s)
- Julia M. Zeh
- Department of Biology, Syracuse University, Syracuse, NY, USA
| | | | - Susan E. Parks
- Department of Biology, Syracuse University, Syracuse, NY, USA
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Cosentino M, Nairn D, Coscarella M, Jackson JC, Windmill JFC. I beg your pardon? Acoustic behaviour of a wild solitary common dolphin who interacts with harbour porpoises. BIOACOUSTICS 2022. [DOI: 10.1080/09524622.2021.1982005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Mel Cosentino
- Bioacoustics Group, Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, UK
| | | | - Mariano Coscarella
- Cesimar – Cct Cenpat -conicet, Puerto Madryn, Argentina
- Universidad Nacional de la Patagonia San Juan Bosco, Puerto Madryn, Argentina
| | - Joseph C. Jackson
- Bioacoustics Group, Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - James F. C. Windmill
- Bioacoustics Group, Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, UK
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Cetacean Acoustic Welfare in Wild and Managed-Care Settings: Gaps and Opportunities. Animals (Basel) 2021; 11:ani11113312. [PMID: 34828040 PMCID: PMC8614506 DOI: 10.3390/ani11113312] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 02/02/2023] Open
Abstract
Simple Summary Whales and dolphins in managed-care and wild settings are exposed to human-made, anthropogenic sounds of varying degrees. These sounds can lead to potential negative welfare outcomes if not managed correctly in zoos or in the open ocean. Current wild regulations are based on generally broad taxa-based hearing thresholds, but there is movement to take other contextual factors into account, partially informed by researchers familiar with work in zoological settings. In this spirit, we present more nuanced future directions for the evaluation of acoustic welfare in both wild and managed-care settings, with suggestions for how research in both domains can inform each other as a means to address the paucity of research available on this topic, especially in managed-care environments. Abstract Cetaceans are potentially at risk of poor welfare due to the animals’ natural reliance on sound and the persistent nature of anthropogenic noise, especially in the wild. Industrial, commercial, and recreational human activity has expanded across the seas, resulting in a propagation of sound with varying frequency characteristics. In many countries, current regulations are based on the potential to induce hearing loss; however, a more nuanced approach is needed when shaping regulations, due to other non-hearing loss effects including activation of the stress response, acoustic masking, frequency shifts, alterations in behavior, and decreased foraging. Cetaceans in managed-care settings share the same acoustic characteristics as their wild counterparts, but face different environmental parameters. There have been steps to integrate work on welfare in the wild and in managed-care contexts, and the domain of acoustics offers the opportunity to inform and connect information from both managed-care settings and the wild. Studies of subjects in managed-care give controls not available to wild studies, yet because of the conservation implications, wild studies on welfare impacts of the acoustic environment on cetaceans have largely been the focus, rather than those in captive settings. A deep integration of wild and managed-care-based acoustic welfare research can complement discovery in both domains, as captive studies can provide greater experimental control, while the more comprehensive domain of wild noise studies can help determine the gaps in managed-care based acoustic welfare science. We advocate for a new paradigm in anthropogenic noise research, recognizing the value that both wild and managed-care research plays in illustrating how noise pollution affects welfare including physiology, behavior, and cognition.
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Martin MJ, Torres Ortiz S, Reyes Reyes MV, Marino A, Iñíguez Bessega M, Wahlberg M. Commerson’s dolphins (Cephalorhynchus commersonii) can relax acoustic crypsis. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03035-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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9
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Malinka CE, Tønnesen P, Dunn CA, Claridge DE, Gridley T, Elwen SH, Teglberg Madsen P. Echolocation click parameters and biosonar behaviour of the dwarf sperm whale ( Kogia sima). J Exp Biol 2021; 224:224/6/jeb240689. [PMID: 33771935 DOI: 10.1242/jeb.240689] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/11/2021] [Indexed: 11/20/2022]
Abstract
Dwarf sperm whales (Kogia sima) are small toothed whales that produce narrow-band high-frequency (NBHF) echolocation clicks. Such NBHF clicks, subject to high levels of acoustic absorption, are usually produced by small, shallow-diving odontocetes, such as porpoises, in keeping with their short-range echolocation and fast click rates. Here, we sought to address the problem of how the little-studied and deep-diving Kogia can hunt with NBHF clicks in the deep sea. Specifically, we tested the hypotheses that Kogia produce NBHF clicks with longer inter-click intervals (ICIs), higher directionality and higher source levels (SLs) compared with other NBHF species. We did this by deploying an autonomous deep-water vertical hydrophone array in the Bahamas, where no other NBHF species are present, and by taking opportunistic recordings of a close-range Kogia sima in a South African harbour. Parameters from on-axis clicks (n=46) in the deep revealed very narrow-band clicks (root mean squared bandwidth, BWRMS, of 3±1 kHz), with SLs of up to 197 dB re. 1 µPa peak-to-peak (μPapp) at 1 m, and a half-power beamwidth of 8.8 deg. Their ICIs (mode of 245 ms) were much longer than those of porpoises (<100 ms), suggesting an inspection range that is longer than detection ranges of single prey, perhaps to facilitate auditory streaming of a complex echo scene. On-axis clicks in the shallow harbour (n=870) had ICIs and SLs in keeping with source parameters of other NBHF cetaceans. Thus, in the deep, dwarf sperm whales use a directional, but short-range echolocation system with moderate SLs, suggesting a reliable mesopelagic prey habitat.
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Affiliation(s)
- Chloe E Malinka
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark
| | - Pernille Tønnesen
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark
| | - Charlotte A Dunn
- Bahamas Marine Mammal Research Organisation (BMMRO), Sandy Point, Abaco, Bahamas.,Sea Mammal Research Unit, University of St Andrews, St Andrews KY16 8LB, UK
| | - Diane E Claridge
- Bahamas Marine Mammal Research Organisation (BMMRO), Sandy Point, Abaco, Bahamas.,Sea Mammal Research Unit, University of St Andrews, St Andrews KY16 8LB, UK
| | - Tess Gridley
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch 7605, South Africa.,Sea Search Research and Conservation, Muizenberg, Cape Town 7945, South Africa
| | - Simon H Elwen
- Department of Botany and Zoology, Stellenbosch University, Stellenbosch 7605, South Africa.,Sea Search Research and Conservation, Muizenberg, Cape Town 7945, South Africa
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10
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Yang L, Sharpe M, Temple AJ, Berggren P. Characterization and comparison of echolocation clicks of white-beaked dolphins (Lagenorhynchus albirostris) off the Northumberland coast, UK. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 149:1498. [PMID: 33765828 DOI: 10.1121/10.0003560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Odontocetes produce ultrasonic clicks for navigation and foraging. These are commonly categorized as regular or buzz clicks based on the inter-click interval. Buzz clicks are linked to foraging behaviors and may be subdivided into slow buzz clicks for prey chase, and regular buzz clicks for prey capture. This study recorded these three click types produced by white-beaked dolphins (Lagenorhynchus albirostris) off the Northumberland coast, UK. Acoustic parameters (including duration, centroid frequency, and root-mean-squared bandwidth) were calculated and compared across the three click types. The results showed that the regular clicks had shorter durations and higher frequencies than both the buzz click types. The regular buzz clicks had longer durations, lower frequencies, and narrower bandwidths than the slow buzz clicks. Additionally, regardless of click type, about 30% of the clicks had high-frequency (200-250 kHz) secondary peaks and >90% of the clicks displayed spectral peak and notch patterns between 20 and 80 kHz. These findings are useful for future quantitative assessment of the echolocation performance of white-beaked dolphins in the wild. The patterns of spectral peaks and notches identified may facilitate for acoustic identification of this species.
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Affiliation(s)
- Liangliang Yang
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Matt Sharpe
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Andrew J Temple
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Per Berggren
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
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11
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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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12
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Pedersen MB, Fahlman A, Borque-Espinosa A, Madsen PT, Jensen FH. Whistling is metabolically cheap for communicating bottlenose dolphins ( Tursiops truncatus). ACTA ACUST UNITED AC 2020; 223:jeb.212498. [PMID: 31796610 DOI: 10.1242/jeb.212498] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 11/26/2019] [Indexed: 11/20/2022]
Abstract
Toothed whales depend on sound for communication and foraging, making them potentially vulnerable to acoustic masking from increasing anthropogenic noise. Masking effects may be ameliorated by higher amplitudes or rates of calling, but such acoustic compensation mechanisms may incur energetic costs if sound production is expensive. The costs of whistling in bottlenose dolphins (Tursiops truncatus) have been reported to be much higher (20% of resting metabolic rate, RMR) than theoretical predictions (0.5-1% of RMR). Here, we address this dichotomy by measuring the change in the resting O2 consumption rate (V̇ O2 ), a proxy for RMR, in three post-absorptive bottlenose dolphins during whistling and silent trials, concurrent with simultaneous measurement of acoustic output using a calibrated hydrophone array. The experimental protocol consisted of a 2-min baseline period to establish RMR, followed by a 2-min voluntary resting surface apnea, with or without whistling as cued by the trainers, and then a 5-min resting period to measure recovery costs. Daily fluctuations in V̇ O2 were accounted for by subtracting the baseline RMR from the recovery costs to estimate the cost of apnea with and without whistles relative to RMR. Analysis of 52 sessions containing 1162 whistles showed that whistling did not increase metabolic cost (P>0.1, +4.2±6.9%) as compared with control trials (-0.5±5.9%; means±s.e.m.). Thus, we reject the hypothesis that whistling is costly for bottlenose dolphins, and conclude that vocal adjustments such as the Lombard response to noise do not represent large direct energetic costs for communicating toothed whales.
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Affiliation(s)
- Michael B Pedersen
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
| | - Andreas Fahlman
- Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain.,Global Diving Research, Ottawa, ON, K2J 5E8
| | - Alicia Borque-Espinosa
- Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain.,University of Valencia, Av. de Blasco Ibáñez, 13, 46010 Valencia, Spain
| | - Peter T Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus C, Denmark
| | - Frants H Jensen
- Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus C, Denmark.,Scottish Oceans Institute, University of St Andrews, East Sands, St Andrews KY16 8LB, UK.,Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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13
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Martin MJ, Elwen SH, Kassanjee R, Gridley T. To buzz or burst-pulse? The functional role of Heaviside's dolphin, Cephalorhynchus heavisidii, rapidly pulsed signals. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.01.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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14
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Kragh IM, McHugh K, Wells RS, Sayigh LS, Janik VM, Tyack PL, Jensen FH. Signal-specific amplitude adjustment to noise in common bottlenose dolphins (Tursiops truncatus). J Exp Biol 2019; 222:jeb.216606. [DOI: 10.1242/jeb.216606] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 11/01/2019] [Indexed: 11/20/2022]
Abstract
Anthropogenic underwater noise has increased over the past century, raising concern about the impact on cetaceans that rely on sound for communication, navigation, and locating prey and predators. Many terrestrial animals increase the amplitude of their acoustic signals to partially compensate for the masking effect of noise (the Lombard response), but it has been suggested that cetaceans almost fully compensate with amplitude adjustments for increasing noise levels. Here, we use sound-recording DTAGs on pairs of free-ranging common bottlenose dolphins (Tursiops truncatus) to test (i) if dolphins increase signal amplitude to compensate for increasing ambient noise and (ii) whether or not adjustments are identical for different signal types. We present evidence of a Lombard response in the range of 0.1-0.3 dB per 1 dB increase in ambient noise, which is similar to that of terrestrial animals, but much lower than the response reported for other cetaceans. We found that signature whistles tended to be louder and with a lower degree of amplitude adjustment to noise compared to non-signature whistles, suggesting that signature whistles may be selected for higher output levels and may have a smaller scope for amplitude adjustment to noise. The consequence of the limited degree of vocal amplitude compensation is a loss of active space during periods of increased noise, with potential consequences for group cohesion, conspecific encounter rates, and mate attraction.
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Affiliation(s)
- Ida M. Kragh
- Zoophysiology, Department of Bioscience, Aarhus University, C. F. Moellers Allé, 8000 Aarhus C, Denmark
| | - Katherine McHugh
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, 1600 Ken Thompson Pkwy, Sarasota, FL 34236, USA
| | - Randall S. Wells
- Chicago Zoological Society's Sarasota Dolphin Research Program, c/o Mote Marine Laboratory, 1600 Ken Thompson Pkwy, Sarasota, FL 34236, USA
| | - Laela S. Sayigh
- Woods Hole Oceanographic Institution, 266 Woods Hole Rd, Woods Hole, MA 02543, USA
- Hampshire College, 893 West Street, Amherst, MA 01002, USA
| | - Vincent M. Janik
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St. Andrews, St. Andrews, KY16 8LB, UK
| | - Peter L. Tyack
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St. Andrews, St. Andrews, KY16 8LB, UK
| | - Frants H. Jensen
- Woods Hole Oceanographic Institution, 266 Woods Hole Rd, Woods Hole, MA 02543, USA
- Aarhus Institute of Advanced Studies, Aarhus University, Hoegh-Guldbergs Gade 6B, 8000 Aarhus C, Denmark
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15
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Galatius A, Olsen MT, Steeman ME, Racicot RA, Bradshaw CD, Kyhn LA, Miller LA. Raising your voice: evolution of narrow-band high-frequency signals in toothed whales (Odontoceti). Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly194] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Anders Galatius
- Department of Bioscience, Aarhus University, Roskilde, Denmark
| | - Morten Tange Olsen
- Evolutionary Genomics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen O, Denmark
| | | | - Rachel A Racicot
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, USA
- The Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA, USA
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN, USA
| | - Catherine D Bradshaw
- School of Geographical Sciences, University of Bristol, Bristol, UK
- Met Office Hadley Centre, Exeter, UK
| | - Line A Kyhn
- Department of Bioscience, Aarhus University, Roskilde, Denmark
| | - Lee A Miller
- Department of Biology, University of Southern Denmark, Odense, Denmark
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Martin MJ, Gridley T, Elwen SH, Jensen FH. Heaviside's dolphins ( Cephalorhynchus heavisidii) relax acoustic crypsis to increase communication range. Proc Biol Sci 2018; 285:rspb.2018.1178. [PMID: 30051842 DOI: 10.1098/rspb.2018.1178] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 06/26/2018] [Indexed: 11/12/2022] Open
Abstract
The costs of predation may exert significant pressure on the mode of communication used by an animal, and many species balance the benefits of communication (e.g. mate attraction) against the potential risk of predation. Four groups of toothed whales have independently evolved narrowband high-frequency (NBHF) echolocation signals. These signals help NBHF species avoid predation through acoustic crypsis by echolocating and communicating at frequencies inaudible to predators such as mammal-eating killer whales. Heaviside's dolphins (Cephalorhynchus heavisidii) are thought to exclusively produce NBHF echolocation clicks with a centroid frequency around 125 kHz and little to no energy below 100 kHz. To test this, we recorded wild Heaviside's dolphins in a sheltered bay in Namibia. We demonstrate that Heaviside's dolphins produce a second type of click with lower frequency and broader bandwidth in a frequency range that is audible to killer whales. These clicks are used in burst-pulses and occasional click series but not foraging buzzes. We evaluate three different hypotheses and conclude that the most likely benefit of these clicks is to decrease transmission directivity and increase conspecific communication range. The expected increase in active space depends on background noise but ranges from 2.5 (Wenz Sea State 6) to 5 times (Wenz Sea State 1) the active space of NBHF signals. This dual click strategy therefore allows these social dolphins to maintain acoustic crypsis during navigation and foraging, and to selectively relax their crypsis to facilitate communication with conspecifics.
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Affiliation(s)
- Morgan J Martin
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, c/o Sea Search Research and Conservation NPC, 4 Bath Rd, Cape Town 7945, South Africa
| | - Tess Gridley
- Centre for Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, c/o Sea Search Research and Conservation NPC, 4 Bath Rd, Cape Town 7945, South Africa
| | - Simon H Elwen
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, c/o Sea Search Research and Conservation NPC, 4 Bath Rd, Cape Town 7945, South Africa
| | - Frants H Jensen
- Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus C, Denmark.,Biology Department, Woods Hole Oceanographic Institution, 266 Woods Hole Rd, Woods Hole, MA 02543, USA
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