Size selective performance of two flexible sorting grid designs in the Northeast Arctic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) fishery

Published source details Sistiaga M., Brinkhof J., Herrmann B., Grimaldo E., Langård L. & Lilleng D. (2016) Size selective performance of two flexible sorting grid designs in the Northeast Arctic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) fishery. Fisheries Research, 183, 340-351.
Share Tweet Email

Actions

This study is summarised as evidence for the following.

	Action	Category
	Use a different design or configuration of size-sorting escape grid/system in trawl fishing gear (bottom and mid-water) Action Link

Use a different design or configuration of size-sorting escape grid/system in trawl fishing gear (bottom and mid-water)

A replicated, controlled study in 2014 in two areas of seabed in the Barents Sea off Norway (Sistiaga et al. 2016) found that using a new type of size-sorting escape grid system (four panel flexigrid) improved the size-selectivity of undersized cod Gadus morhua but not haddock Melanogrammus aeglefinus compared to a conventional two panel design. For cod, the length at which fish had a 50% chance of escape from the combined grids of the new four panel system was greater compared to the conventional grid system in one of two trials (new: 42 cm, conventional: 18 cm) and was similar in the other (new: 36 cm, conventional: 31 cm). For haddock, there was no difference in the 50% escape length between grid systems in one of one trial at Bear Island (new: 36 cm, conventional: 33 cm). In addition, the four panel grid system retained fewer undersized cod than the conventional grid, but there were no differences in the sizes of haddock caught between grids (data reported as selectivity curves). Data were collected in October 2014 from 51 trawl deployments on a commercial trawler on two separate fishing grounds around Bear Island and Hopen. Separate deployments were made using either a trawl net with a new four panel flexible double grid system (28 hauls) or a conventional two panel system (23 hauls). Both trawls had 138 mm diamond mesh codends. See original paper for full gear specifications. Small mesh covers over each of the grids collected fish escaping through each grid system. The lengths of cod and haddock retained in the codends and covers were measured.

(Summarised by: Chris Barrett)