Porpoise Alerting Device (PAL): Synthetic harbour porpoise (Phocoena phocoena) communication signals influence behaviour and reduce by-catch

  • Published source details Culik B., Dorrien C. von & Conrad M. (2016) Porpoise Alerting Device (PAL): Synthetic harbour porpoise (Phocoena phocoena) communication signals influence behaviour and reduce by-catch. Progress in Marine Conservation Europe, Stralsund, Germany. BfN-Skripten, 451, 150-155.


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 2013–2014 of two pelagic areas in the North Sea and Baltic Sea, Denmark and Germany (Culik et al. 2016) found that fishing nets with acoustic devices attached had fewer harbour porpoise Phocoena phocoena entanglements than nets without devices in one area but not the other. In the Baltic Sea, no porpoises were entangled in nets with acoustic devices, whereas nine porpoises were entangled in nets without acoustic devices. In the North Sea, the number of entangled porpoises did not differ significantly between nets with acoustic devices (two porpoises) or without (three porpoises). In 2013–2014, commercial fishing vessels simultaneously deployed gill nets (number not reported) with and without acoustic devices across two areas. Acoustic devices (‘PALfi’ Porpoise Alerting Devices) emitted three synthetic porpoise alert calls/minute (1.3 second sweeps consisting of 700 clicks centred at 133 kHz). Devices were attached to the headrope of gill nets, spaced 200 m apart. Fishers reported entangled porpoises. Some fishing trips were additionally monitored by onboard video equipment and scientific observers (number not reported).

    (Summarised by: Anna Berthinussen)

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