Assessment of long-distance detection of gillnets by porpoises:Reply to Dawson and Lusseau

Nielsen et al. (2012; Mar Ecol Prog Ser 453:241-248) analyzed surface observations of harbour porpoises in a small coastal area where a modified gillnet was introduced at randomized time intervals. The study concluded that porpoises reacted to the gillnet at surprisingly large distances (in some cas...

Full description

Bibliographic Details
Published in:Marine Ecology Progress Series
Main Authors: Nielsen, Torben, Wahlberg, Magnus, Dabelsteen, Torben
Format: Article in Journal/Newspaper
Language:English
Published: 2013
Subjects:
Online Access:https://portal.findresearcher.sdu.dk/da/publications/c97dc130-7e6f-4769-9de6-81df8801e34b
https://doi.org/10.3354/meps10338
Description
Summary:Nielsen et al. (2012; Mar Ecol Prog Ser 453:241-248) analyzed surface observations of harbour porpoises in a small coastal area where a modified gillnet was introduced at randomized time intervals. The study concluded that porpoises reacted to the gillnet at surprisingly large distances (in some cases >80 m). Dawson & Lusseau (2013; Mar Ecol Prog Ser 478:301-302) argue that the conclusions of Nielsen et al. (2012) are undermined by pseudo-replication (a matter of concern in many field studies of marine mammals). We acknowledge these concerns, but we think that the conclusions of Nielsen et al. (2012) remain valid, as the data are best explained by harbour porpoises being able to detect and avoid gillnets at very long ranges.