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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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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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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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4
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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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5
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Cosentino M, Guarato F, Tougaard J, Nairn D, Jackson JC, Windmill JFC. Porpoise click classifier (PorCC): A high-accuracy classifier to study harbour porpoises (Phocoena phocoena) in the wild. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 145:3427. [PMID: 31255141 DOI: 10.1121/1.5110908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 05/20/2019] [Indexed: 06/09/2023]
Abstract
Harbour porpoises are well-suited for passive acoustic monitoring (PAM) as they produce highly stereotyped narrow-band high-frequency (NBHF) echolocation clicks. PAM systems must be coupled with a classification algorithm to identify the signals of interest. Here, the authors present a harbour porpoise click classifier (PorCC) developed in matlab, which uses the coefficients of two logistic regression models in a decision-making pathway to assign candidate signals to one of three categories: high-quality clicks (HQ), low-quality clicks (LQ), or high-frequency noise. The receiver operating characteristics of PorCC was compared to that of PAMGuard's Porpoise Click Detector/Classifier Module. PorCC outperformed PAMGuard's classifier achieving higher hit rates (correctly classified clicks) and lower false alarm levels (noise classified as HQ or LQ clicks). Additionally, the detectability index (d') for HQ clicks for PAMGuard was 2.2 (overall d' = 2.0) versus 4.1 for PorCC (overall d' = 3.4). PorCC classification algorithm is a rapid and highly accurate method to classify NBHF clicks, which could be applied for real time monitoring, as well as to study harbour porpoises, and potentially other NBHF species, throughout their distribution range from data collected using towed hydrophones or static recorders. Moreover, PorCC is suitable for studies of acoustic communication of porpoises.
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Affiliation(s)
- Mel Cosentino
- Bioacoustics Group, Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, 99 George Street, G1 1RD Glasgow, United Kingdom
| | - Francesco Guarato
- Bioacoustics Group, Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, 99 George Street, G1 1RD Glasgow, United Kingdom
| | - Jakob Tougaard
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - David Nairn
- Clyde Porpoise CIC, 1-1 Allanton Park Terrace, KA29 0AW Fairlie, United Kingdom
| | - Joseph C Jackson
- Bioacoustics Group, Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, 99 George Street, G1 1RD Glasgow, United Kingdom
| | - James F C Windmill
- Bioacoustics Group, Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, 99 George Street, G1 1RD Glasgow, United Kingdom
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6
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Sørensen PM, Wisniewska DM, Jensen FH, Johnson M, Teilmann J, Madsen PT. Click communication in wild harbour porpoises (Phocoena phocoena). Sci Rep 2018; 8:9702. [PMID: 29946073 PMCID: PMC6018799 DOI: 10.1038/s41598-018-28022-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/13/2018] [Indexed: 11/09/2022] Open
Abstract
Social delphinids employ a vocal repertoire of clicks for echolocation and whistles for communication. Conversely, the less social and acoustically cryptic harbour porpoises (Phocoena phocoena) only produce narrow-band high-frequency (NBHF) clicks with properties that appear poorly suited for communication. Nevertheless, these small odontocetes likely mediate social interactions, such as mate choice and mother-calf contact, with sound. Here, we deployed six tags (DTAG3) on wild porpoises in Danish waters for a total of 96 hours to investigate if the patterns and use of stereotyped NBHF click trains are consistent with a communication function. We show that wild porpoises produce frequent (up to 27 • min-1), high-repetition rate click series with repetition rates and output levels different from those of foraging buzzes. These sounds are produced in bouts and frequently co-occur with emission of similar sounds by nearby conspecifics, audible on the tags for >10% of the time. These results suggest that social interactions are more important to this species than their limited social encounters at the surface may indicate and that these interactions are mediated by at least two broad categories of calls composed of short, high-repetition rate click trains that may encode information via the repetition rate of their stereotyped NBHF clicks.
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Affiliation(s)
- P M Sørensen
- Zoophysiology, Department of Bioscience, Aarhus University, C.F. Moellers Allé 3, DK-8000, Aarhus C, Denmark.
| | - D M Wisniewska
- Zoophysiology, Department of Bioscience, Aarhus University, C.F. Moellers Allé 3, DK-8000, Aarhus C, Denmark.,Hopkins Marine Station, Stanford University, 120 Ocean View Blvd, Pacific Grove, CA, 93950, USA
| | - F H Jensen
- Aarhus Institute of Advanced Studies, Aarhus University, DK, Høegh-Guldbergs Gade 6b, 8000, Aarhus C, Denmark
| | - M Johnson
- Zoophysiology, Department of Bioscience, Aarhus University, C.F. Moellers Allé 3, DK-8000, Aarhus C, Denmark.,Sea Mammal Research Unit, Scottish Oceans Institute, University of St. Andrews, St. Andrews, Fife, KY16 8LB, United Kingdom
| | - J Teilmann
- Marine Mammal Research, Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - P T Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, C.F. Moellers Allé 3, DK-8000, Aarhus C, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, DK, Høegh-Guldbergs Gade 6b, 8000, Aarhus C, Denmark
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Wisniewska DM, Teilmann J, Hermannsen L, Johnson M, Miller LA, Siebert U, Madsen PT. Quantitative Measures of Anthropogenic Noise on Harbor Porpoises: Testing the Reliability of Acoustic Tag Recordings. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 875:1237-42. [PMID: 26611092 DOI: 10.1007/978-1-4939-2981-8_155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
In recent years, several sound and movement recording tags have been developed to sample the acoustic field experienced by cetaceans and their reactions to it. However, little is known about how tag placement and an animal's orientation in the sound field affect the reliability of on-animal recordings as proxies for actual exposure. Here, we quantify sound exposure levels recorded with a DTAG-3 tag on a captive harbor porpoise exposed to vessel noise in a controlled acoustic environment. Results show that flow noise is limiting onboard noise recordings, whereas no evidence of body shading has been found for frequencies of 2-20 kHz.
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Affiliation(s)
- Danuta M Wisniewska
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark.
| | - Jonas Teilmann
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000, Roskilde, Denmark.
| | - Line Hermannsen
- Department of Bioscience, Aarhus University, 8000, Aarhus C, Denmark.
| | - Mark Johnson
- Sea Mammal Research Unit (SMRU), Scottish Oceans Institute, University of St. Andrews, St. Andrews, Fife, KY16 8LB, UK.
| | - Lee A Miller
- Department of Biology, University of Southern Denmark, 5230, Odense M, Denmark.
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover, Foundation, 30173, Hannover, Germany.
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Culik B, von Dorrien C, Müller V, Conrad M. Synthetic communication signals influence wild harbour porpoise ( Phocoena phocoena) behaviour. BIOACOUSTICS 2015. [DOI: 10.1080/09524622.2015.1023848] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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Tougaard J, Wright AJ, Madsen PT. Cetacean noise criteria revisited in the light of proposed exposure limits for harbour porpoises. MARINE POLLUTION BULLETIN 2015; 90:196-208. [PMID: 25467877 DOI: 10.1016/j.marpolbul.2014.10.051] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 05/17/2023]
Abstract
The impact of underwater noise on marine life calls for identification of exposure criteria to inform mitigation. Here we review recent experimental evidence with focus on the high-frequency cetaceans and discuss scientifically-based initial exposure criteria. A range of new TTS experiments suggest that harbour and finless porpoises are more sensitive to sound than expected from extrapolations based on results from bottlenose dolphins. Furthermore, the results from TTS experiments and field studies of behavioural reactions to noise, suggest that response thresholds and TTS critically depend on stimulus frequency. Sound exposure levels for pure tones that induce TTS are reasonably consistent at about 100 dB above the hearing threshold for pure tones and sound pressure thresholds for avoidance reactions are in the range of 40-50 dB above the hearing threshold. We propose that frequency weighting with a filter function approximating the inversed audiogram might be appropriate when assessing impact.
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Affiliation(s)
- Jakob Tougaard
- Aarhus University, Department of Bioscience, Frederiksborgvej 399, DK-4000 Roskilde, Denmark.
| | - Andrew J Wright
- Aarhus University, Department of Bioscience, Frederiksborgvej 399, DK-4000 Roskilde, Denmark; Department of Environmental Science and Policy, George Mason University, 4400 University Drive, Fairfax, VA 22030, USA
| | - Peter T Madsen
- Aarhus University, Department of Bioscience, DK-8000 Aarhus C, Denmark; Murdoch University Cetacean Research Unit, Murdoch University, WA, Australia
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10
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Kimura S, Akamatsu T, Wang D, Li S, Wang K, Yoda K. Variation in the production rate of biosonar signals in freshwater porpoises. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 133:3128-3134. [PMID: 23654415 DOI: 10.1121/1.4796129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The biosonar (click train) production rate of ten Yangtze finless porpoises and their behavior were examined using animal-borne data loggers. The sound production rate varied from 0 to 290 click trains per 10-min time interval. Large individual differences were observed, regardless of body size. Taken together, however, sound production did not differ significantly between daytime and nighttime. Over the 172.5 h of analyzed recordings, an average of 99.0% of the click trains were produced within intervals of less than 60 s, indicating that during a 1-min interval, the number of click trains produced by each porpoise was typically greater than one. Most of the porpoises exhibited differences in average swimming speed and depth between day and night. Swimming speed reductions and usage of short-range sonar, which relates to prey-capture attempts, were observed more often during nighttime. However, biosonar appears to be affected not only by porpoise foraging, but also by their sensory environment, i.e., the turbid Yangtze River system. These features will be useful for passive acoustic detection of the porpoises. Calculations of porpoise density or abundance should be conducted carefully because large individual differences in the sound production rate will lead to large estimation error.
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Affiliation(s)
- Satoko Kimura
- Graduate School of Environmental Studies, Nagoya University, Nagoya, 464-8601, Japan.
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Lemonds DW, Kloepper LN, Nachtigall PE, Au WWL, Vlachos SA, Branstetter BK. A re-evaluation of auditory filter shape in delphinid odontocetes: evidence of constant-bandwidth filters. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2011; 130:3107-3114. [PMID: 22087939 DOI: 10.1121/1.3644912] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The auditory filter shape of delphinid odontocetes was previously considered to be typically mammalian constant-quality in which filter bandwidths increase proportionally with frequency. Recent studies with porpoises demonstrate constant-bandwidth portions of the auditory filter. The critical ratios for a bottlenose dolphin were measured between 40 and 120 kHz by behaviorally determining the subject's ability to detect pure tones in the presence of white noise. Critical ratios as a function of frequency were constant, indicating the auditory filter acts as a constant-bandwidth system in this frequency range. Re-analysis of past studies supports these findings, and suggests the delphinid auditory system is best characterized as a constant-Q system below 40 kHz and a constant-bandwidth-like system between 40 kHz and 120 kHz before returning to a constant Q pattern at the highest frequencies.
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Affiliation(s)
- D W Lemonds
- Lockeed Martin, 3375 Koapaka Street, Suite I-500, Honolulu, Hawaii 96819, USA
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CLAUSEN KARINTUBBERT, WAHLBERG MAGNUS, BEEDHOLM KRISTIAN, DERUITER STACY, MADSEN PETERTEGLBERG. CLICK COMMUNICATION IN HARBOUR PORPOISESPHOCOENA PHOCOENA. BIOACOUSTICS 2011. [DOI: 10.1080/09524622.2011.9753630] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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13
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Kastelein RA, Hoek L, de Jong CAF, Wensveen PJ. The effect of signal duration on the underwater detection thresholds of a harbor porpoise (Phocoena phocoena) for single frequency-modulated tonal signals between 0.25 and 160 kHz. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2010; 128:3211-22. [PMID: 21110616 DOI: 10.1121/1.3493435] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The underwater hearing sensitivity of a young male harbor porpoise for tonal signals of various signal durations was quantified by using a behavioral psychophysical technique. The animal was trained to respond only when it detected an acoustic signal. Fifty percent detection thresholds were obtained for tonal signals (15 frequencies between 0.25-160 kHz, durations 0.5-5000 ms depending on the frequency; 134 frequency-duration combinations in total). Detection thresholds were quantified by varying signal amplitude by the 1-up 1-down staircase method. The hearing thresholds increased when the signal duration fell below the time constant of integration. The time constants, derived from an exponential model of integration [Plomp and Bouman, J. Acoust. Soc. Am. 31, 749-758 (1959)], varied from 629 ms at 2 kHz to 39 ms at 64 kHz. The integration times of the porpoises were similar to those of other mammals including humans, even though the porpoise is a marine mammal and a hearing specialist. The results enable more accurate estimations of the distances at which porpoises can detect short-duration environmental tonal signals. The audiogram thresholds presented by Kastelein et al. [J. Acoust. Soc. Am. 112, 334-344 (2002)], after correction for the frequency bandwidth of the FM signals, are similar to the results of the present study for signals of 1500 ms duration. Harbor porpoise hearing is more sensitive between 2 and 10 kHz, and less sensitive above 10 kHz, than formerly believed.
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Affiliation(s)
- Ronald A Kastelein
- Sea Mammal Research Company, Julianalaan 46, 3843 CC Harderwijk, The Netherlands
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14
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Kyhn LA, Jensen FH, Beedholm K, Tougaard J, Hansen M, Madsen PT. Echolocation in sympatric Peale's dolphins (Lagenorhynchus australis) and Commerson's dolphins (Cephalorhynchus commersonii) producing narrow-band high-frequency clicks. J Exp Biol 2010; 213:1940-9. [DOI: 10.1242/jeb.042440] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
An increasing number of smaller odontocetes have recently been shown to produce stereotyped narrow-band high-frequency (NBHF) echolocation clicks. Click source parameters of NBHF clicks are very similar, and it is unclear whether the sonars of individual NBHF species are adapted to specific habitats or the presence of other NBHF species. Here, we test whether sympatric NBHF species sharing the same habitat show similar adaptations in their echolocation clicks and whether their clicks display signs of character displacement. Wide-band sound recordings were obtained with a six-element hydrophone array from wild Peale's (Lagenorhynchus australis) and Commerson's (Cephalorhynchus commersonii) dolphins off the Falkland Islands. The centroid frequency was different between Commerson's (133±2 kHz) and Peale's (129±3 kHz) dolphins. The r.m.s. bandwidth was 12±3 kHz for both species. The source level was higher for Peale's dolphin (185±6 dB re 1 μPa p.–p.) than for Commerson's (177±5 dB re 1 μPa p.–p.). The mean directivity indexes were 25 dB for both species. The relatively low source levels in combination with the high directivity index may be an adaptation to reduce clutter when foraging in a coastal environment. We conclude that the small species-specific shifts in distribution of centroid frequencies around 130 kHz may reflect character displacement in otherwise-stereotyped NBHF clicks.
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Affiliation(s)
- L. A. Kyhn
- National Environmental Research Institute, Department of Arctic Environment, Aarhus University, Frederiksborgvej 399, DK-4000, Roskilde, Denmark
- Zoophysiology, Department of Biological Sciences, Aarhus University, C. F. Møllers Allé Building 1131, DK-8000 Aarhus, Denmark
| | - F. H. Jensen
- Zoophysiology, Department of Biological Sciences, Aarhus University, C. F. Møllers Allé Building 1131, DK-8000 Aarhus, Denmark
| | - K. Beedholm
- Zoophysiology, Department of Biological Sciences, Aarhus University, C. F. Møllers Allé Building 1131, DK-8000 Aarhus, Denmark
| | - J. Tougaard
- National Environmental Research Institute, Department of Arctic Environment, Aarhus University, Frederiksborgvej 399, DK-4000, Roskilde, Denmark
| | - M. Hansen
- Zoophysiology, Department of Biological Sciences, Aarhus University, C. F. Møllers Allé Building 1131, DK-8000 Aarhus, Denmark
| | - P. T. Madsen
- Zoophysiology, Department of Biological Sciences, Aarhus University, C. F. Møllers Allé Building 1131, DK-8000 Aarhus, Denmark
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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15
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DeRuiter SL, Hansen M, Koopman HN, Westgate AJ, Tyack PL, Madsen PT. Propagation of narrow-band-high-frequency clicks: measured and modeled transmission loss of porpoise-like clicks in porpoise habitats. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2010; 127:560-567. [PMID: 20059001 DOI: 10.1121/1.3257203] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Estimating the range at which harbor porpoises can detect prey items and environmental objects is integral to understanding their biosonar. Understanding the ranges at which they can use echolocation to detect and avoid obstacles is particularly important for strategies to reduce bycatch. Transmission loss (TL) during acoustic propagation is an important determinant of those detection ranges, and it also influences animal detection functions used in passive acoustic monitoring. However, common assumptions regarding TL have rarely been tested. Here, TL of synthetic porpoise clicks was measured in porpoise habitats in Canada and Denmark, and field data were compared with spherical spreading law and ray-trace (Bellhop) model predictions. Both models matched mean observations quite well in most cases, indicating that a spherical spreading law can usually provide an accurate first-order estimate of TL for porpoise sounds in porpoise habitat. However, TL varied significantly (+/-10 dB) between sites and over time in response to variability in seafloor characteristics, sound-speed profiles, and other short-timescale environmental fluctuations. Such variability should be taken into account in estimates of the ranges at which porpoises can communicate acoustically, detect echolocation targets, and be detected via passive acoustic monitoring.
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Affiliation(s)
- Stacy L DeRuiter
- IFREMER, Service Acoustique et Sismique, BP 70, 29280 Plouzane, France
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16
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Kastelein RA, Wensveen PJ, Hoek L, Au WWL, Terhune JM, de Jong CAF. Critical ratios in harbor porpoises (Phocoena phocoena) for tonal signals between 0.315 and 150 kHz in random Gaussian white noise. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2009; 126:1588. [PMID: 19739772 DOI: 10.1121/1.3177274] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A psychoacoustic behavioral technique was used to determine the critical ratios (CRs) of two harbor porpoises for tonal signals with frequencies between 0.315 and 150 kHz, in random Gaussian white noise. The masked 50% detection hearing thresholds were measured using a "go/no-go" response paradigm and an up-down staircase psychometric method. CRs were determined at one masking noise level for each test frequency and were similar in both animals. For signals between 0.315 and 4 kHz, the CRs were relatively constant at around 18 dB. Between 4 and 150 kHz the CR increased gradually from 18 to 39 dB ( approximately 3.3 dB/octave). Generally harbor porpoises can detect tonal signals in Gaussian white noise slightly better than most odontocetes tested so far. By combining the mean CRs found in the present study with the spectrum level of the background noise levels at sea, the basic audiogram, and the directivity index, the detection threshold levels of harbor porpoises for tonal signals in various sea states can be calculated.
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Affiliation(s)
- Ronald A Kastelein
- Sea Mammal Research Company, Julianalaan 46, Harderwijk, The Netherlands.
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