The effect of strengthening bags on cod-end selectivity of a Scottish demersal trawl
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Published source details
Kynoch R.J., O’Dea M.C. & O’Neill F.G. (2004) The effect of strengthening bags on cod-end selectivity of a Scottish demersal trawl. Fisheries Research, 68, 249-257.
Published source details Kynoch R.J., O’Dea M.C. & O’Neill F.G. (2004) The effect of strengthening bags on cod-end selectivity of a Scottish demersal trawl. Fisheries Research, 68, 249-257.
Actions
This study is summarised as evidence for the following.
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Modify the design or configuration of trawl gear (mixed measures) Action Link |
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Modify the design or configuration of trawl gear (mixed measures)
A replicated, controlled study in 2001 in an area of seabed in the North Sea, off the Orkney Islands, UK (Kynoch et al. 2004) found that modifying a bottom trawl by removing the strengthening bag (a large-mesh cover to prevent the codend from splitting when catch is heavy) improved the size-selectivity of haddock Melanogrammus aeglefinus at two mesh sizes. The length at which haddock had a 50% chance of escape was higher without a strengthening bag at both 110 mm codend mesh size (without: 31.4 cm, with: 31.4 cm) and 120 mm mesh codend (without: 34.3 cm, with: 32.4 cm). A total of 26 trawl deployments were completed on a commercial fishing vessel in June 2001: seven each with a 110 mm codend, with and without a strengthening bag, and six each with a 120 mm codend, with and without a strengthening bag (all diamond mesh). Hauls were 120–198 minutes at 68–87 m depth. The strengthening bag used 265 mm diamond mesh and 6 mm diameter twine (see original paper for full gear specifications). A cover attached over the codends sampled fish that escaped through the meshes. Codend and cover catches were sampled, and fish lengths recorded.
(Summarised by: Chris Barrett)
