Seal exclusion devices in cod pots prevent seal bycatch and affect their catchability of cod

  • Published source details Konigson S., Lovgren J., Hjelm J., Ovegard M., Ljunghager F. & Lunneryd S.G. (2015) Seal exclusion devices in cod pots prevent seal bycatch and affect their catchability of cod. Fisheries Research, 167, 114-122.


This study is summarised as evidence for the following.

Action Category

Modify fishing pots and traps to exclude mammals

Action Link
Marine and Freshwater Mammal Conservation
  1. Modify fishing pots and traps to exclude mammals

    A replicated, controlled study in 2009–2010 of three pelagic sites in the Baltic Sea and one seabed site in the North Sea, Sweden (Konigson et al. 2015) found that fishing pots with metal frames installed had fewer trapped grey seals Halichoerus grypus and harbour seals Phoca vitulina than conventional pots. No seals were trapped in pots with metal frames installed, whereas 3–9 seals/site (11 grey seals and 13 harbour seals in total) were trapped in conventional pots without metal frames. Catches of target cod Gadus spp. varied with different designs of metal frame (see original paper for details). In 2009–2010, baited fishing pots (with two chambers and 1–2 entrances) were deployed in 5–12 floating strings of ≤8 pots (three sites), or individually with ≤6 pots secured to the seabed (one site). The pots were deployed for a total of 2–20 months without metal frames installed followed by 3–10 months with frames. Metal frames of five designs were vertically mounted to the narrow end of pot entrances (see original paper for details). Fishers or observers on board fishing vessels checked the pots every 1–28 days in 2009–2010 and recorded the number and species of trapped seals.

    (Summarised by: Anna Berthinussen)

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