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  • 1
    Online Resource
    Online Resource
    Individual variability of echolocation and diving behavior of Yangtze finless porpoises
    Acoustical Society of America (ASA) ; 2012
    In:  The Journal of the Acoustical Society of America Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3493-3493
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3493-3493
    Abstract: Passive acoustic monitoring has been widely applied to observe the presence, movement and behavior of the target species. For quantitative analysis, the acoustic cue production rate of the target animals must be observed in advance. We examined the detailed pattern of biosonar and swimming behaviors of 10 Yangtze finless porpoises (1 female and 9 males) obtained by electronic tags attached to the animals. The click trains produced by the tagged animal were identified out of other animals' vocalizations using bearing angles calculated by the time-of- arrival differences of the sounds between the two hydrophones in the acoustic tag. The number of click trains produced in 10 min did not relate to the body size or sex and varied from 0 to 290. Although deeper the animals dive, faster they swam, the speed or maximum depth of the animals had no correlation with the number of click trains produced or body size. All parameters we examined had no diurnal rhythm but had independent aperiodic variation. The sound production rate without day or night bias is suitable for the quantitative passive acoustic monitoring of this species.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4709200
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2012
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    An inter-individual communication biotelemetry system using Pseudo-random noise (Gold code)
    Acoustical Society of America (ASA) ; 2016
    In:  Journal of the Acoustical Society of America Vol. 140, No. 4_Supplement ( 2016-10-01), p. 3305-3305
    Details
    In: Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 140, No. 4_Supplement ( 2016-10-01), p. 3305-3305
    Abstract: Recently, bio-logging techniques involving electronic data-storage tags (data-logger) and acoustic transmitters have been increasingly used to understand migratory fish movements and behaviors. The monitoring of migratory fish can provide important insights into the marine ecosystem dynamics. The number of tags data-loggers used, however, is normally limited due to cost and the data-logger recovery rate is usually low. Therefore, we developed a new system that combines the acoustic communication and data logger. In other words, a data-logger that can share data with each other. One of the challenges is to develop an inter-individual communication biotelemetry system based on hydro-acoustic methods. In this system, we used the phase modulation of pseudo-random noise (Gold code). At the final stage of development, we will be doing conduct a field test of this inter-individual communication biotelemetry system on wild herrings and bonitos in the open sea. We expect this new technology to help overcome the bottleneck of the conventional bio-logging and bio-telemetry, and lead to a breakthrough in marine ecosystem studies.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4970525
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2016
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  • 3
    Online Resource
    Online Resource
    Comparison of stationary acoustic monitoring and visual observation of finless porpoises
    Acoustical Society of America (ASA) ; 2009
    In:  The Journal of the Acoustical Society of America Vol. 125, No. 1 ( 2009-01-01), p. 547-553
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 125, No. 1 ( 2009-01-01), p. 547-553
    Abstract: The detection performance regarding stationary acoustic monitoring of Yangtze finless porpoises Neophocaena phocaenoides asiaeorientalis was compared to visual observations. Three stereo acoustic data loggers (A-tag) were placed at different locations near the confluence of Poyang Lake and the Yangtze River, China. The presence and number of porpoises were determined acoustically and visually during each 1-min time bin. On average, porpoises were acoustically detected 81.7±9.7% of the entire effective observation time, while the presence of animals was confirmed visually 12.7±11.0% of the entire time. Acoustic monitoring indicated areas of high and low porpoise densities that were consistent with visual observations. The direction of porpoise movement was monitored using stereo beams, which agreed with visual observations at all monitoring locations. Acoustic and visual methods could determine group sizes up to five and ten individuals, respectively. While the acoustic monitoring method had the advantage of high detection probability, it tended to underestimate group size due to the limited resolution of sound source bearing angles. The stationary acoustic monitoring method proved to be a practical and useful alternative to visual observations, especially in areas of low porpoise density for long-term monitoring.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3021302
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2009
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  • 4
    Online Resource
    Online Resource
    Acoustic capture-recapture method for towed acoustic surveys of echolocating porpoises
    Acoustical Society of America (ASA) ; 2014
    In:  The Journal of the Acoustical Society of America Vol. 135, No. 6 ( 2014-06-01), p. 3364-3370
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 135, No. 6 ( 2014-06-01), p. 3364-3370
    Abstract: Passive acoustic monitoring for cetaceans mainly employ fixed-location methods or point transect samplings; an acoustic survey from a moving platform to conduct line transects is less common. In this study, acoustic capture–recapture by combining a double-observer method with line transect sampling was performed to observe Yangtze finless porpoises. Two acoustic devices were towed with the distance between them varying 0.5 to 89.5 m. The conditional probabilities that both devices would detect the porpoises within the same time window were calculated. In a 1-s time window, it became smaller as the distance between the devices increased, approaching zero when the distance between them was more than 50 m. It was considered that the devices with less than 50 m distance detected the same signals from the same animals, which means the identical detection. When the distance between them is too great, the recapture rate is reduced and the incidence of false matching may increase. Thus, a separation distance of around 50 m between two devices in acoustic capture–recapture of Yangtze finless porpoises was recommended. Note that the performance of the double detections can change depending on the particular device used and on animal behaviors such as vocalizing interval, ship avoidance.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4875710
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2014
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  • 5
    Online Resource
    Online Resource
    Distribution pattern of finless porpoises at the junction of the Yangtze River and Poyang Lake observed by towed passive acoustic device
    Acoustical Society of America (ASA) ; 2011
    In:  The Journal of the Acoustical Society of America Vol. 130, No. 4_Supplement ( 2011-10-01), p. 2460-2460
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 130, No. 4_Supplement ( 2011-10-01), p. 2460-2460
    Abstract: The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) is an endangered freshwater porpoise subspecies unique to the Yangtze River basin. Without immediate conservation measures, it could soon become extinct, just as the Yangtze River dolphin (baiji, Lipotes vexillifer). We report seasonal change in the local distribution of the porpoises living in the conjunction area of the middle reaches of the Yangtze River, side streams, and appended Poyang Lake. A towed stereo acoustic data-logger, A-tag, was used to detect echolocation signals and sound source bearing angles. The independent sound source directions provided the number of animals present, not just the number of sounds. Passive acoustic surveys were performed regularly from May 2007 to August 2010. The water level was highest in August (summer) and lowest in February (winter) and at mid-level in May (spring) and November (autumn). The average number of porpoises detected in 11 surveys conducted in different seasons varied from 0.53 to 1.26 individuals per km. No significant trend of reducing number of porpoises was detected during 3-y monitoring. The distribution of the porpoises was seasonally site-specific. In May and August, the animals were detected more often at river junctions than in the lake, but vice versa from November to February.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3654880
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2011
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  • 6
    Online Resource
    Online Resource
    Density estimation of Yangtze finless porpoises using passive acoustic sensors and automated click train detection
    Acoustical Society of America (ASA) ; 2010
    In:  The Journal of the Acoustical Society of America Vol. 128, No. 3 ( 2010-09-01), p. 1435-1445
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 128, No. 3 ( 2010-09-01), p. 1435-1445
    Abstract: A method is presented to estimate the density of finless porpoises using stationed passive acoustic monitoring. The number of click trains detected by stereo acoustic data loggers (A-tag) was converted to an estimate of the density of porpoises. First, an automated off-line filter was developed to detect a click train among noise, and the detection and false-alarm rates were calculated. Second, a density estimation model was proposed. The cue-production rate was measured by biologging experiments. The probability of detecting a cue and the area size were calculated from the source level, beam patterns, and a sound-propagation model. The effect of group size on the cue-detection rate was examined. Third, the proposed model was applied to estimate the density of finless porpoises at four locations from the Yangtze River to the inside of Poyang Lake. The estimated mean density of porpoises in a day decreased from the main stream to the lake. Long-term monitoring during 466 days from June 2007 to May 2009 showed variation in the density 0–4.79. However, the density was fewer than 1 porpoise/km2 during 94% of the period. These results suggest a potential gap and seasonal migration of the population in the bottleneck of Poyang Lake.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3442574
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2010
    detail.hit.zdb_id: 1461063-2
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