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.

Validating passive acoustic monitoring data loggers by visual observations

2008 ◽  
Vol 123 (5) ◽  
pp. 3208-3208
Author(s):  
Line A. Kyhn ◽  
Jakob Tougaard ◽  
Mats Amundin ◽  
Joanna Stenback ◽  
Jonas Teilmann ◽  
...  
Keyword(s):  
Acoustic Monitoring ◽  
Monitoring Data ◽  
Passive Acoustic Monitoring ◽  
Data Loggers ◽  
Passive Acoustic ◽  
Visual Observations

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 Passive acoustic monitoring of the bottlenose dolphin Tursiops truncatus to determine continuous presence in Ensenada de La Paz, Mexico

2021 ◽  
Vol 55 (3) ◽  
pp. 238
Author(s):  
Marco FW Gauger ◽  
Javier Caraveo-Patiño ◽  
Eduardo Romero-Vivas
Keyword(s):  
Bottlenose Dolphin ◽  
Tursiops Truncatus ◽  
Gulf Of California ◽  
Bottlenose Dolphins ◽  
Acoustic Monitoring ◽  
Passive Acoustic Monitoring ◽  
La Paz ◽  
Custom Made ◽  
Continuous Presence ◽  
Passive Acoustic

Bottlenose dolphins (Tursiops truncatus) are ecosystem sentinels. In the Gulf of California, Mexico, they are found in areas that overlap with human activities, as in the case of the Ensenada de La Paz lagoon. A custom-made recorder -moored at medium depth (2.0 m) in the entrance to the lagoon- recorded acoustic data from June to November 2017 (8 deployments; 293 h). Whistles -an indicative of bottlenose dolphin presences- were pooled over time to acquire acoustic encounters, which were analysed to infer continuity of animal presence and test for statistically significant differences between deployments, day and night, and hours. Whistles were recorded during all deployments and evidenced night-time presence of bottlenose dolphins in the lagoon. Significant differences of acoustic encounters were observed between ‘Jun-Jul’ and ‘Sep-Nov’. Acoustic encounters were higher at night but were not different at an hourly level. Acoustical data proved the continuous presence of bottlenose dolphins, highlighting the importance of the Ensenada de La Paz for their population. This initial study highlights the usefulness of long-term passive acoustic monitoring to inform stake holders involved in management and conservation plans.

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