Study

Size selection of redfish (Sebastes spp.) in a double grid system: Estimating escapement through individual grids and comparison to former grid trials

  • Published source details Larsen R.B., Herrmann B., Sistiaga M., Grimaldo E., Tatone I. & Onandia I. (2016) Size selection of redfish (Sebastes spp.) in a double grid system: Estimating escapement through individual grids and comparison to former grid trials. Fisheries Research, 183, 385-395

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
Marine Fish Conservation
  1. 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 2015 of two seabed areas in the Norwegian and Barents Sea, off Norway (Larsen et al. 2016) found that using a new type of size-sorting escape grid system (four panel double grid) did not improve the size-selectivity of unwanted redfish Sebastes spp., compared to two existing commercial grid systems. The likelihood of redfish being retained at any given length was similar between the new double grid system compared to one of two existing grid systems (Sort-X), but compared to the other existing grid (Sort-V), the new grid retained more redfish between 35–50 cm (data presented as retention probability curves). Data were collected for the new double grid system in February-March 2015, from a total of 19 trawl deployments by a trawler on fishing grounds off the coast of Finnmark and Troms, north Norway. The gear used was a four-panel section of net with two steel sorting grids (upper and lower) fitted in front of a 138 mm diamond mesh codend. The lower grid had 55 mm bar spacing and replaced the polyethylene lifting panel of an existing mandatory steel grid section, and the upper grid was a standard steel grid (Sort-V type) with 55 mm bar spacing (see paper for specifications). Two small mesh covers over each grid collected fish escaping through them. The lengths of redfish >20 cm caught in the codend and covers were measured. Escape data were compared with data previously obtained for single Sort-V and Sort-X grid systems (see original paper for details).

    (Summarised by: Natasha Taylor)

Output references

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