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  • 1
    Online Resource
    Online Resource
    Monitoring noise levels and delphinid presence through autonomous acoustic in Rio de Janeiro coastal area
    Acoustical Society of America (ASA) ; 2018
    In:  The Journal of the Acoustical Society of America Vol. 144, No. 3_Supplement ( 2018-09-01), p. 1885-1885
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 144, No. 3_Supplement ( 2018-09-01), p. 1885-1885
    Abstract: In order to investigate the soundscape in a Rio de Janeiro coast site, passive acoustic monitoring was conducted during two non-consecutive weeks in the summer of 2015/2016 by deploying one SM2M + device. The equipment recorded at a 66% duty cycle with sample rate of 96 kHz and 36 dB gain. Third octave levels (TOLs) were calculated for all recordings through PAMGuide software. To search for delphinid presence, a band limited energy detector was employed using Raven 1.5 in a 512 Hann window, 50% overlap. TOLs varied across frequencies and day hours. Light hours were noisier than dark hours in 25 frequency bands (MW, p & lt;0.01), with highest mean level being measured at 794 Hz at 06am (105.4 ± 5.4 dB re 1μPa), and lowest mean level measured at 39.8 kHz at 01am (80.3 ± 3.7 dB re 1μPa). A total of 281 delphinid sound emissions were detected in nine occasions, seven during week 1 and two during week 2. Seven detection events occurred during dark hours. Although more than one species of delphinid is known to occur in Rio de Janeiro coast, these results indicate a frequent nocturnal use of the area, which was only possible to observe through autonomous monitoring.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.5068264
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2018
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    Nocturnal distribution of Guiana dolphins ( Sotalia guianensis ) in a coastal bay: Using the help of local fisherman and passive acoustic monitoring
    Acoustical Society of America (ASA) ; 2020
    In:  The Journal of the Acoustical Society of America Vol. 148, No. 4_Supplement ( 2020-10-01), p. 2481-2481
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 148, No. 4_Supplement ( 2020-10-01), p. 2481-2481
    Abstract: Overlap between dolphin distribution and fishing activities can lead to accidental by-catch. Assessing the nocturnal distribution of a resident population of dolphins can help highlight sensitive areas where by-catch occurs. The goal of this study was to use passive acoustics equipment deployed by local fisherman in different areas of Sepetiba Bay, southeastern Brazil, to assess Guiana dolphins' distribution at night. In total, 64 recording sessions and 316 hours were collected at a sampling rate of 96 kHz, covering the period between 18:00 and 04:00. To detect Guiana dolphin sounds a Raven pro 1.5 band limited energy detector was defined between frequencies of 25 and 48 kHz and SNR & gt;5dB. An experienced observer validated detections, quantifying according to time and area of occurrence. Guiana dolphins were more frequently encountered in two major areas, where they were present between 68% and 33% of recorded hours. The mean concentration of sounds/hour in the bay was 72 (±113), ranging from 0.6 to 325 across areas. In one location, there was also a higher concentration of detections between 18:00 and 19:00. Future work should rely on local knowledge of fisherman to detect major fishing areas during the night and help creating Guiana dolphin conservation plans.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.5146876
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2020
    detail.hit.zdb_id: 1461063-2
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  • 3
    Online Resource
    Online Resource
    Source levels and propagation modelling of whistles from a free-ranging rough-toothed dolphin
    Acoustical Society of America (ASA) ; 2020
    In:  The Journal of the Acoustical Society of America Vol. 148, No. 4_Supplement ( 2020-10-01), p. 2633-2633
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 148, No. 4_Supplement ( 2020-10-01), p. 2633-2633
    Abstract: A lone adult individual of rough-toothed-dolphin had its acoustic behavior recorded with a calibrated system (Fostex FR22: 192 kHz sampling rate; C54 hydrophone: -165.0 dBV, 0.009 Hz–100 kHz). Moments when the animal approached and faced the hydrophone were noted. Whistles were counted in Raven 1.6 (Hann window, 512, 50% overlap). Duration (ms), minimum, maximum and peak frequencies (kHz), number of steps and step frequency (kHz) were extracted of whistles emitted when the animal was in a 1-m radius of the hydrophone. Source levels (SL) were estimated through power spectral density calculation in Matlab. SL at frequency parameters and at each whistle step were extracted and used in bellhop propagation models of a coastal scenario. 63 whistles were emitted within 1m. Frequencies ranged from 1.2 to 9.7 kHz and duration from 115.3 to 825.6 ms. Frequency and SL increased with step number, with 4.5 steps per whistle. Minimum frequencies (1.9 ± 0.6 kHz) had smaller SL (125.2 ± 4.2 dB re 1 μPa) and decreased to 100 dB before 500 m. Peak frequencies (6.7 ± 1.0 kHz) had mean SL of 149.5 ± 8.5 dB re 1 μPa and reached 2500 m with 100 dB. Higher frequencies reached longer distances and depths.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.5147323
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2020
    detail.hit.zdb_id: 1461063-2
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  • 4
    Online Resource
    Online Resource
    Characteristics of Guiana dolphins ( Sotalia guianensis ) burst-pulse sounds emitted during different surface activity rates in Rio de Janeiro’s coast
    Acoustical Society of America (ASA) ; 2018
    In:  The Journal of the Acoustical Society of America Vol. 144, No. 3_Supplement ( 2018-09-01), p. 1978-1978
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 144, No. 3_Supplement ( 2018-09-01), p. 1978-1978
    Abstract: Burst-pulses are still the least studied signals in delphinid acoustic repertoire. In this study, acoustic data were gathered in two Rio de Janeiro coastal bays where groups of Guiana dolphins can be found regularly. The acoustic equipment consisted of a C54XRS hydrophone (-155.8 dBV, 0.006 Hz a 203 kHz) and a Fostex digital recorder (192 kHz sampling rate). During each recording, the surface activity rate of the group was classified as being high or low. Burst-pulses were analyzed using SoundRuler software. Fifty signals were randomly selected and the values for duration (low = 143.9 ± 145.4; high = 82.2 ± 74.8), interpulse interval (low = 2.81 ± 1.92; high = 1.34 ± 1.35), number of pulses (low = 52.6 ± 55.7; high = 71.6 ± 64.5), peak frequency (low = 37.4 ± 2.5; high = 38.5 ± 3.2), and minimum frequency (low = 15.4 ± 6.5; high = 6.7 ± 5.3) were measured. Additionally, a Mann-Whitney U test compared all acoustic parameters of burst-pulses emitted during both surface activity rates. Significant differences between activity rates were found for interpulse interval (p & lt;0.01) and minimum frequency (p & lt;0.01). This scenario could indicate that some burst-pulse parameters are related to group arousal and behavior.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.5068636
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2018
    detail.hit.zdb_id: 1461063-2
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