Size selectivity of redfish (Sebastes spp.) in the Northeast Atlantic using grid-based selection systems for trawls

Published source details Herrmann B., Sistiaga M., Larsen R.B. & Nielsen K.N. (2013) Size selectivity of redfish (Sebastes spp.) in the Northeast Atlantic using grid-based selection systems for trawls. Aquatic Living Resources, 26, 109-120.
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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 study in 1992 in waters in the Northeast Atlantic off Norway (Herrmann et al. 2013) found that using a different configuration of size-sorting escape grid (increased bar spacing) in a fish trawl improved the size-selectivity of unwanted redfish Sebastes spp. The average length at which redfish had a 50% chance of escape via the grid was greater for the widest bar spacing and increased with increasing bar spacing (50 mm: 35 cm, 45 mm: 30 cm, 40 mm: 28 cm). Data were collected in March 1992 from 17 deployments of a trawl fitted with a two-grid size-sorting system (Sort-X) of one of three grid bar spacings: 50 mm (12 hauls), 45 mm grid (three hauls) and 40 mm grid (two hauls). A small mesh cover attached over the grid collected fish escaping through it while a small mesh inner lining in the codend prevented fish escaping through the codend meshes. The number and lengths of redfish collected in both the cover and codend were recorded.

(Summarised by: Leo Clarke)