Estimation of the detection probability for Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis) with a passive acoustic method

2008 ◽  
Vol 123 (6) ◽  
pp. 4403-4411 ◽  
Author(s):  
T. Akamatsu ◽  
D. Wang ◽  
K. Wang ◽  
S. Li ◽  
S. Dong ◽  
...  
2021 ◽  
Vol 9 (1) ◽  
pp. 44
Author(s):  
Maria Ceraulo ◽  
María Paz Sal Moyano ◽  
Fernando Jose Hidalgo ◽  
María Cielo Bazterrica ◽  
Salvatore Mazzola ◽  
...  

Human-generated underwater noise and its effect on marine biota is recognized as an important issue. Boat noise can affect the communication success of fish species that use sounds for spawning purposes. During the reproductive period, males of the black drum Pogonias spp. produce calls ranging from 90 Hz to 300 Hz. In the Mar Chiquita coastal lagoon (Buenos Aires, Argentina), Pogonias courbina is one of the primary fishing species. Although no regulation is directly applied to protect it, a ban protects the reproductive period of other fish species during weekdays. Here, we investigated the potential effect of boat noise on P. courbina vocalizations through a passive acoustic method. Acoustic data were collected, and P. courbina calls were identified and counted. The files with boat noise passages were categorized into classes according to their noise frequency range (A = below 700 Hz, B = over 700 Hz, and C = below and above 700 Hz). The fish call rate was lower in files where boat noise overlapped the fish call frequency (Classes A and C). Only boat noise from Class C was significantly reduced during days with the active fishing ban. These results suggest that anthropogenic noise may affect the P. courbina call rate and underline the importance of including the evaluation of anthropogenic noise in the current management of the area.


2017 ◽  
Vol 43 (5) ◽  
pp. 993-997
Author(s):  
Alfredo Borie ◽  
Natalia P.A. Bezerra ◽  
Sebastian A.L. Klarian ◽  
Paulo Travassos

Acoustic ecology is an emerging and poorly known field of research. Soundscape has been used to infer the behavior of several species in different environments and can serve as a reliable indicator of the habitat type and quality; also, it is believed that it is an important factor for larvae orientation in settlement areas. We used the passive acoustic method to evaluate the soundscape of a management and exploitation area of benthic resources, a rocky reef area in central Chile. It was possible to hear a continuous cracking sound during recording and underwater observations. We detected two distinct frequency bands with similar parameters during the night and day, a band between 90 and 300 Hz, which corresponded to the effects of sea waves (geophony), and a frequency band with a range of 1,500 to 2,700 Hz (biophony), with a fundamental frequency of 2,070 Hz. Both bands had similar energy (~88.0 dB re: 1V/µPa). These results show the relevant acoustic activity in the area, which may have important ecological implications for the recruitment of commercially important benthic resources.


PLoS ONE ◽  
2018 ◽  
Vol 13 (7) ◽  
pp. e0199396 ◽  
Author(s):  
Stiele V. Hagens ◽  
Anthony R. Rendall ◽  
Desley A. Whisson

2006 ◽  
Vol 23 (4) ◽  
pp. 599-618 ◽  
Author(s):  
Richard Manasseh ◽  
Alexander V. Babanin ◽  
Cameron Forbes ◽  
Kate Rickards ◽  
Irena Bobevski ◽  
...  

Abstract A passive acoustic method of detecting breaking waves of different scales has been developed. The method also showed promise for measuring breaking severity. Sounds were measured by a subsurface hydrophone in various wind and wave states. A video record of the surface was made simultaneously. Individual sound pulses corresponding to the many individual bubble formations during wave-breaking events typically last only a few tens of milliseconds. Each time a sound-level threshold was exceeded, the acoustic signal was captured over a brief window typical of a bubble formation pulse, registering one count. Each pulse was also analyzed to determine the likely bubble size generating the pulse. Using the time series of counts and visual observations of the video record, the sound-level threshold that detected bubble formations at a rate optimally discriminating between breaking and nonbreaking waves was determined by a classification-accuracy analysis. This diagnosis of breaking waves was found to be approximately 70%–75% accurate once the optimum threshold had been determined. The method was then used for detailed analysis of wave-breaking properties across the spectrum. When applied to real field data, a breaking probability distribution could be obtained. This is the rate of occurrence of wave-breaking events at different wave scales. With support from a separate, laboratory experiment, the estimated bubble size is argued to be dependent on the severity of wave breaking and thus to provide information on the energy loss due to the breaking at the measured spectral frequencies. A combination of the breaking probability distribution and the bubble size could lead to direct estimates of spectral distribution of wave dissipation.


Author(s):  
S. A. Gavriliev ◽  
M. V. Ivanov

A passive acoustic method is proposed for monitoring the dispersed composition of air bubbles, which determines the efficiency of wastewater treatment in facilities with aeration systems, in treatment facilities with aeration systems. The principal possibility of applying the method has been demonstrated on an experimental plant assembled on the basis of a flotation column. The size of the bubbles created by the flotation column aeration system was determined photometrically. It is shown that the error in determining the bubble radii by the proposed method relative to the photometric method was no more than 17.5%.


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