Avoidance of unwanted bycatch in the blue whiting fishery in Faroese Fishing Zone by use of a sorting grid system

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Due to bycatch of unwanted species as saithe (Pollachius virens), mackerel (Scomber scombrus), and redfish (Sebastes marinus) in the blue whiting (Micromesistius poutassou) fishery in Faroese fishing zone, the Faroese and Russian fishery authorities decided in 2006 to introduce a special sorting grid system when fishing for blue whiting. This system is mandatory to use in large parts in the Faroese fishing zone. The system consists of a special sorting grid with 55 mm bar space, inserted in a netting section in front of the cod-end. In front of the sorting grid a small leading panel was inserted to lead the blue whiting from the escape opening for by-catch below the sorting grid. Video recordings were used to observe the behaviour of blue whiting in front of the sorting grid. To estimate the amount of the by-catch and the loss of blue whiting the alternate trawl haul method was used. Experiments in 2008 were used to analyse the amount of blue whiting escaping with unwanted species, comparison of unwanted species quantity in presence/absence of the sorting system in the trawl. By using the sorting grid a decrease of bycatch of saithe was obtained ranging from 1.46–3 times, and of all unwanted species (saithe, mackerel, redfish, and haddock) the reduction was 0.25–3.25 times. The efficiency of the sorting grid system as a management tool depends on the abundance of bycatch in the blue whiting fishery.