Bycatch of vulnerable species: Understanding the process and mitigating the impacts

  • Published source details Northridge S., Kingston A., Mackay A. & Lonergan M. (2011) Bycatch of vulnerable species: Understanding the process and mitigating the impacts. Sea Mammal Research Unit (SMRU) report, Report to DEFRA (project ref. MF1003).


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 controlled study in 2008–2011 of a pelagic area in the North Atlantic Ocean, off the coast of southwest England, UK (Northridge et al. 2011) found that fishing nets with acoustic devices attached had fewer entanglements of harbour porpoises Phocoena phocoena than nets without acoustic devices. Porpoise entanglement rates were lower in fishing nets with acoustic devices attached (0.007 porpoises/haul) than in those without acoustic devices (0.02 porpoises/haul). Fishing vessels (>12 m) deployed fleets of gill nets (up to 8 km in length) with acoustic devices attached (total 999 hauls) and without acoustic devices (total 907 hauls). Dolphin Dissuasive Devices (model DDD-02, STM Products) were either attached to the middle of each section of 20 net panels (in 2008) or to the end ropes and 10 m above the anchor (in 2009–2011). Between August 2008 and April 2011, entangled porpoises were recorded during each haul by independent observers (1,709 hauls) or fishers (197 hauls).

    (Summarised by: Anna Berthinussen)

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