The cosmos grid: a new design for reducing by-catch in the Nordic shrimp fishery

  • Published source details Grimaldo E. & Larsen R.B. (2005) The cosmos grid: a new design for reducing by-catch in the Nordic shrimp fishery. Fisheries Research, 76, 187-197.


This study is summarised as evidence for the following.

Action Category

Fit a size-sorting escape grid (rigid or flexible) to a prawn/shrimp trawl net

Action Link
Marine Fish Conservation
  1. Fit a size-sorting escape grid (rigid or flexible) to a prawn/shrimp trawl net

    A replicated, controlled study in 2002 of two bottom fishing grounds in the Greenland Sea, off western Svalbard, Norway (Grimaldo & Larsen 2005) found that shrimp trawl nets fitted with size-sorting escape grids (two designs) allowed high quantities of Greenland halibut Reinhardtius hippoglossoides, cod Gadus morhua, haddock Melanogrammus aeglefinus and saithe Pollachius virens to escape capture, but the amounts and sizes of fish released did not differ between grid designs. Average overall reductions in catch weight for four of four species were similar between grid designs (new: 35–184 kg, old: 33–121 kg) representing releases of 81–99% and 69–99% of the fish captured for each grid respectively. The selection length (the length at which fish have a 50% chance of escape) did not differ between grid designs for all four species (new: 14.3–20.2 cm, old: 16.3–19.5 cm). In addition, average catch losses of target Nordic shrimp Pandalus borealis were low (4–5%) for both grids. Trials took place in the areas of Ice Fjord and Minke Bank in December 2002 in depths of 240–415 m. Deployments of trawl nets fitted with either a new design of grid (24 tows) made of lighter artificial materials (Cosmos) or an established grid (10 tows) of high-density material (HDPE) were made (see paper for grid specifications). Each grid had 19 mm bar spacings. A top cover collected escaping fish and shrimp. Cover and codend catches of fish and shrimp were weighed and fish lengths recorded.

    (Summarised by: Chris Barrett)

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