An investigation of acoustic deterrent devices to reduce cetacean bycatch in an inshore set net fishery

  • Published source details Hardy T., Williams R., Caslake R. & Tregenza N. (2012) An investigation of acoustic deterrent devices to reduce cetacean bycatch in an inshore set net fishery. Journal of Cetacean Research and Management, 12, 85-90.


This study is summarised as evidence for the following.

Action Category

Use acoustic devices on fishing gear

Action Link
Marine and Freshwater Mammal Conservation
  1. Use acoustic devices on fishing gear

    A replicated, controlled study in 2009–2010 of three pelagic sites in the Celtic Sea, off the coast of Cornwall, UK (Hardy et al. 2012) found that fishing nets with acoustic devices had lower echolocation activity of harbour porpoises Phocoena phocoena around them than nets without acoustic devices. Overall, 35–51% fewer harbour porpoise clicks were recorded at nets with acoustic devices (total 800–20,000 clicks/site) than at nets without acoustic devices (total 2,000–40,000 clicks/site). Only one entangled porpoise was found during the study, in a net without an acoustic device. Three commercial fishing vessels deployed pairs of ‘tangle’ nets (267 mm mesh; number not reported) between April 2009 and April 2010. Each pair had an experimental net with acoustic devices attached (Aquatec AQUAmark 100, spaced 200 m apart) and a control net with no devices. Acoustic devices emitted 400 ms pulses at 20–140 kHz. Each pair of nets was deployed for approximately five days at depths of 20–100 m to target benthic fish species. Acoustic detectors attached to the nets recorded porpoise echolocation clicks during a total of 640 days in 2009–2010.

    (Summarised by: Anna Berthinussen)

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