Dear colleagues,
I am pleased to announce the publication of the following open access paper in 
Bioacoustics: https://www.tandfonline.com/doi/full/10.1080/09524622.2018.1477071
https://doi.org/10.1080/09524622.2018.1477071
Karin Tubbert Clausen, Jakob Tougaard, Jacob Carstensen, Matthieu Delefosse & 
Jonas Teilmann (2018): Noise affects porpoise click detections - the magnitude 
of the effect depends on logger type and detection filter settings, 
Bioacoustics, DOI: 10.1080/09524622.2018.1477071
Abstract
Automatic click detectors and full-bandwidth sound recorders are widely used in 
passive acoustic monitoring of small cetaceans. Detection of these signals 
depends on a variety of factors, including signal to noise ratio. Passive 
acoustic monitoring is often used to study impact of underwater noise on small 
cetaceans, but as detection probability is affected by changes in signal to 
noise ratio, variable noise levels may affect conclusions drawn from these 
experiments. Therefore, we examine how different detectors and filters perform 
in varying ocean noise conditions. C-PODs and full-bandwidth recorders 
(Wildlife Acoustics, SM2M+) were deployed at two stations in an environment 
with fluctuating ambient noise for 42 days. Noise level and harbour porpoise 
(Phocoena phocoena) click trains simultaneously recorded on both loggers were 
compared. Overall, we found that porpoise click detections by the algorithm 
used to analyse full-band recorder data (Pamguard) paralleled detections by the 
C-POD. However, Pamguard detected significantly more clicks than the C-POD. A 
decrease in detections was seen for both loggers with increasing noise in the 
band 20 -160 kHz, in particular for levels above 100 dB re 1μPa rms. We also 
found that the Pamguard detection function changed the least over varying noise 
conditions when compared to the C-POD detectors. This study sheds light on the 
fact that inference of animal presence/absence or density that are based on 
echolocation cues (here, Porpoise Positive Minutes) shall account for the 
acoustic environments where probability of detecting signals may be affected by 
variability in ambient noise levels.
Best regards
Jonas Teilmann
_______________________________________________
Jonas Teilmann
Senior Scientist, Ph.D.
Phone: (+45) 21 42 42 91
Fax: (+45) 87 16 87 51
E-mail: j...@bios.au.dk<mailto:j...@bios.au.dk>

Marine Mammal Research Section
Department of Bioscience
Aarhus University
Frederiksborgvej 399
DK-4000 Roskilde
Denmark
http://bios.au.dk/en/about-bioscience/organisation/marine-mammal-research/
https://www.facebook.com/Aarhus-University-Section-for-Marine-Mammal-Research-1481125835511699/



_______________________________________________
MARMAM mailing list
MARMAM@lists.uvic.ca
https://lists.uvic.ca/mailman/listinfo/marmam

Reply via email to