Advanced Technique for Automatic Detection and Discrimination of a Click Train With Short Interclick Intervals From the Clicks of Ganges River Dolphins (Platanista gangetica gangetica) Recorded by a Passive Acoustic Monitoring System Using Hydrophone Arrays

2014 ◽  
Vol 48 (3) ◽  
pp. 167-181 ◽  
Author(s):  
Harumi Sugimatsu ◽  
Junichi Kojima ◽  
Tamaki Ura ◽  
Rajendar Bahl ◽  
Sandeep Behera ◽  
...  

AbstractTo understand the biosonar click characteristics of Ganges river dolphins (adults, young adults, and calves) in a wild environment along with periodic visual observations, an ongoing program for long-term in situ monitoring has been carried out using a passive acoustic monitoring (PAM) system. During monitoring phase 4 (2012), migrating Ganges river dolphin groups with small calves were visually observed, and click trains having a short interclick interval (ICI: from 6 to 12 ms) were concurrently found from the acoustic data corresponding to the period. Click trains having a short ICI have also been observed in other small-toothed whales during foraging and socializing activities (called buzz) (Thoms, Moss, & Vater, 2004; Simard & Mann, 2008). For analysis of the short ICI click trains produced by the Ganges river dolphins, an advanced technique that automatically detects and discriminates a “short ICI click train” from other click sequences during the selected periods of data recorded by a PAM system was developed. For a robust algorithm, a smaller mean ICI caused by overlapping click trains from multiple dolphins that fulfill the range of ICI values that may get incorrectly labeled as “short ICI click train” was considered to judiciously detect a reliable click train. By applying the selected parameters and ICI values (default or given), the performance of the proposed technique was demonstrated using sample data. The results showed the reliability of the technique for the extraction of a variety of short ICI click trains from other click trains.

Fishes ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 36 ◽  
Author(s):  
Adelaide Lindseth ◽  
Phillip Lobel

Soundscape ecology is a rapidly growing field with approximately 93% of all scientific articles on this topic having been published since 2010 (total about 610 publications since 1985). Current acoustic technology is also advancing rapidly, enabling new devices with voluminous data storage and automatic signal detection to define sounds. Future uses of passive acoustic monitoring (PAM) include biodiversity assessments, monitoring habitat health, and locating spawning fishes. This paper provides a review of ambient sound and soundscape ecology, fish acoustic monitoring, current recording and sampling methods used in long-term PAM, and parameters/metrics used in acoustic data analysis.


2011 ◽  
Vol 130 (4) ◽  
pp. 2536-2536
Author(s):  
Marc O. Lammers ◽  
Lisa Munger ◽  
Pollyanna Fisher Pool ◽  
Kevin Wong ◽  
Whitlow W. L. Au ◽  
...  

2021 ◽  
pp. 53-78
Author(s):  
Anne-Sophie Crunchant ◽  
Chanakya Dev Nakka ◽  
Jason T. Isaacs ◽  
Alex K. Piel

Animals share acoustic space to communicate vocally. The employment of passive acoustic monitoring to establish a better understanding of acoustic communities has emerged as an important tool in assessing overall diversity and habitat integrity as well as informing species conservation strategies. This chapter aims to review how traditional and more emerging bioacoustic techniques can address conservation issues. Acoustic data can be used to estimate species occupancy, population abundance, and animal density. More broadly, biodiversity can be assessed via acoustic diversity indices, using the number of acoustically conspicuous species. Finally, changes to the local soundscape provide an early warning of habitat disturbance, including habitat loss and fragmentation. Like other emerging technologies, passive acoustic monitoring (PAM) benefits from an interdisciplinary collaboration between biologists, engineers, and bioinformaticians to develop detection algorithms for specific species that reduce time-consuming manual data mining. The chapter also describes different methods to process, visualize, and analyse acoustic data, from open source to commercial software. The technological advances in bioacoustics turning heavy, non-portable, and expensive hardware and labour and time-intensive methods for analysis into new small, movable, affordable, and automated systems, make acoustic sensors increasingly popular among conservation biologists for all taxa.


PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260485
Author(s):  
Manuel Castellote ◽  
Aran Mooney ◽  
Russel Andrews ◽  
Stacy Deruiter ◽  
Wu-Jung Lee ◽  
...  

Cook Inlet, Alaska, is home to an endangered and declining population of 279 belugas (Delphinapterus leucas). Recovery efforts highlight a paucity of basic ecological knowledge, impeding the correct assessment of threats and the development of recovery actions. In particular, information on diet and foraging habitat is very limited for this population. Passive acoustic monitoring has proven to be an efficient approach to monitor beluga distribution and seasonal occurrence. Identifying acoustic foraging behavior could help address the current gap in information on diet and foraging habitat. To address this conservation challenge, eight belugas from a comparative, healthy population in Bristol Bay, Alaska, were instrumented with a multi-sensor tag (DTAG), a satellite tag, and a stomach temperature transmitter in August 2014 and May 2016. DTAG deployments provided 129.6 hours of data including foraging and social behavioral states. A total of 68 echolocation click trains ending in terminal buzzes were identified during successful prey chasing and capture, as well as during social interactions. Of these, 37 click trains were successfully processed to measure inter-click intervals (ICI) and ICI trend in their buzzing section. Terminal buzzes with short ICI (minimum ICI <8.98 ms) and consistently decreasing ICI trend (ICI increment range <1.49 ms) were exclusively associated with feeding behavior. This dual metric was applied to acoustic data from one acoustic mooring within the Cook Inlet beluga critical habitat as an example of the application of detecting feeding in long-term passive acoustic monitoring data. This approach allowed description of the relationship between beluga presence, feeding occurrence, and the timing of spawning runs by different species of anadromous fish. Results reflected a clear preference for the Susitna River delta during eulachon (Thaleichthys pacificus), Chinook (Oncorhynchus tshawytscha), pink (Oncorhynchus gorbuscha), and coho (Oncorhynchus kisutch) salmon spawning run periods, with increased feeding occurrence at the peak of the Chinook and pink salmon runs.


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