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

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.

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Evaluating the Effects of Offshore Pile Driving on Phocoena phocoena (Harbor Porpoises) by Using Passive Acoustic Monitoring

Advances in Experimental Medicine and Biology - The Effects of Noise on Aquatic Life ◽

10.1007/978-1-4419-7311-5_63 ◽

2012 ◽

pp. 285-287 ◽

Cited By ~ 2

Author(s):

Klaus Lucke ◽

Michael Dähne ◽

Sven Adler ◽

Anja Brandecker ◽

Kathrin Krügel ◽

...

Keyword(s):

Acoustic Monitoring ◽

Pile Driving ◽

Phocoena Phocoena ◽

Passive Acoustic Monitoring ◽

Passive Acoustic ◽

Harbor Porpoises

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

10.22541/au.162755770.03327482/v1 ◽

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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