scholarly journals Presentation of Binning-Based Inter-Click Interval Data from Passive Acoustic Monitoring of Free-Ranging Harbour Porpoises (Phocoena Phocoena)

2020 ◽  
Vol 25 (2) ◽  
pp. 209-218
Author(s):  
Maximilian Ruffert ◽  
Victoria L.G. Todd ◽  
Ian B. Todd
Keyword(s):  
Interval Data ◽  
Acoustic Monitoring ◽  
Phocoena Phocoena ◽  
Passive Acoustic Monitoring ◽  
Equal Rate ◽  
Click Train ◽  
Judicious Choice ◽  
Binned Data ◽  
Passive Acoustic ◽  
Free Ranging

C-PODs are used for Passive Acoustic Monitoring (PAM) of harbour porpoises (Phocoena phocoena) at an offshore open sea location in the German North Sea. Diel patterns of echolocation click trains are extracted from minimum inter-click interval (minICI) data by binning. The aim of this study is to reassess and refine minICI ranges of click train data with particular consideration to the binning widths. Emphasis is also placed on choosing an appropriate visualisation of these binned data. Key ecological results include presence of higher train rates during the day with intermediate minICI values defined by the range 6-28 ms and a higher train rate with short minICI values 1.25-2.00 ms at night. This indicates an increase in porpoise feeding behaviour, or change of style, at night. Click trains with long minICI values > 35 ms occur at an equal rate throughout both diel phases, suggesting a more routine behaviour, such as navigation. Results could be revealed only by judicious choice of binning widths, e.g. previously overlooked patterns within historical echolocation data. The classification methodology can be used to analyse echolocation trains from a variety of species and can be applied to any PAM data with the relevant click parameters.

scholarly journals Comparing Distribution of Harbour Porpoises (Phocoena phocoena) Derived from Satellite Telemetry and Passive Acoustic Monitoring

PLoS ONE ◽  
2016 ◽  
Vol 11 (7) ◽  
pp. e0158788 ◽  
Author(s):  
Lonnie Mikkelsen ◽  
Frank F. Rigét ◽  
Line A. Kyhn ◽  
Signe Sveegaard ◽  
Rune Dietz ◽  
...  
Keyword(s):  
Satellite Telemetry ◽  
Acoustic Monitoring ◽  
Phocoena Phocoena ◽  
Passive Acoustic Monitoring ◽  
Passive Acoustic

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 ◽  
...  
Keyword(s):  
Acoustic Monitoring ◽  
Ganges River ◽  
Passive Acoustic Monitoring ◽  
Advanced Technique ◽  
Acoustic Data ◽  
Click Train ◽  
Passive Acoustic ◽  
The Ganges

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.

scholarly journals Echolocation inter-click interval variation among specific behaviours in free-ranging bottlenose dolphins from the coast of Uruguay

2020 ◽  
Vol 21 (1) ◽  
pp. 141-149
Author(s):  
Javier Tellechea
Keyword(s):  
Natural Environment ◽  
Protected Area ◽  
Marine Protected Area ◽  
Bottlenose Dolphins ◽  
Acoustic Monitoring ◽  
Passive Acoustic Monitoring ◽  
Passive Acoustic ◽  
Free Ranging ◽  
Visual Observations

To assess whether behaviour can be inferred from echolocation trains (inter-click intervals) this study examines acoustic recordings of free-ranging bottlenose dolphins using Passive Acoustic Monitoring (PAM). Inter-click intervals from 17 groups of free-ranging bottlenose dolphins were monitored over a 36 day period in an area within the Cerro Verde (Marine Protected Area), Uruguay. Simultaneous visual observations were made from shore nearby. Results show that inter-click intervals in the echolocation trains had significant differences for three specific behaviours: feeding, socialising and travelling. The natural environment was quiet, with no disturbances in the immediate vicinity from boats, drones or other man-made noises.

scholarly journals Estimating the abundance of the critically endangered Baltic Proper harbour porpoise (Phocoena phocoena) population using passive acoustic monitoring

2021 ◽  
Author(s):  
Mats Amundin ◽  
Julia Carlström ◽  
Len Thomas ◽  
Ida Carlén ◽  
Jens Koblitz ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Acoustic Monitoring ◽  
Harbour Porpoise ◽  
Critically Endangered ◽  
Phocoena Phocoena ◽  
Passive Acoustic Monitoring ◽  
Animal Populations ◽  
Baltic Proper ◽  
The Baltic ◽  
Passive Acoustic

Knowing the abundance of a population is a crucial component to assess its conservation status and develop effective conservation plans. For most cetaceans, abundance estimation is difficult given their cryptic and mobile nature, especially when the population is small and has a transnational distribution. In the Baltic Sea, the number of harbour porpoises (Phocoena phocoena) has collapsed since the mid-20th century and the Baltic Proper harbour porpoise is listed as Critically Endangered by the IUCN; however, its abundance remains unknown. Here, one of the largest ever passive acoustic monitoring studies was carried out by eight Baltic Sea nations to estimate the abundance of the Baltic Proper harbour porpoise for the first time. By logging porpoise echolocation signals at 298 stations during May 2011-April 2013, calibrating the loggers’ spatial detection performance at sea, and measuring the click rate of tagged individuals, we estimated an abundance of 66-1,143 individuals (95% CI, point estimate 490) during May-October within the population’s proposed management border. The small abundance estimate strongly supports that the Baltic Proper harbour porpoise is facing an extremely high risk of extinction, and highlights the need for immediate and efficient conservation actions through international cooperation. It also provides a starting point in monitoring the trend of the population abundance to evaluate the effectiveness of management measures and determine its interactions with the larger neighbouring Belt Sea population. Further, we offer evidence that design-based passive acoustic monitoring can generate reliable estimates of the abundance of rare and cryptic animal populations across large spatial scales.

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