Diamond vs. square mesh codend in a multi-species trawl fishery of the western Mediterranean: effects on catch composition, yield, size selectivity and discards
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Published source details
Ordines F., Massutí E., Guijarro B. & Mas R. (2006) Diamond vs. square mesh codend in a multi-species trawl fishery of the western Mediterranean: effects on catch composition, yield, size selectivity and discards. Aquatic Living Resources, 19, 329-338.
Published source details Ordines F., Massutí E., Guijarro B. & Mas R. (2006) Diamond vs. square mesh codend in a multi-species trawl fishery of the western Mediterranean: effects on catch composition, yield, size selectivity and discards. Aquatic Living Resources, 19, 329-338.
Actions
This study is summarised as evidence for the following.
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Use a square mesh instead of a diamond mesh codend in a trawl net Action Link |
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Use a square mesh instead of a diamond mesh codend in a trawl net
A replicated, controlled study in 2002–2003 in two areas of seabed on the continental shelf in the Mediterranean Sea, Spain (Ordines et al. 2006, same experimental set-up as Guijarro & Massuti 2006) found that using a square mesh instead of diamond mesh codend in a multi-species bottom trawl fishery reduced the amount of fish discarded in deeper but not shallower shelf areas, and size-selectivity was improved in both areas. Average catch biomass of total discarded fish (80–90% of which were non-commercial species) was lower in the square mesh codend on the deep shelf (square: 10, diamond: 20 kg/30 min) and similar between mesh shapes on the shallow shelf (square: 6, diamond: 10 kg/30 min). The length at which 50% of fish are predicted to escape, where reported, was higher in the square mesh in both shallow and deep areas for all fish (square: 7–29 cm, diamond: 2–19 cm; see paper for species individual data). Fishing deployments were conducted from a commercial trawler in September–October 2002 and May–June 2003 (same experimental set-up as Guijarro & Massuti, 2006), on the shallow (50–78 m, 12 hauls) and deep (147–189 m, 12 hauls) continental shelf off the Balearic Islands. Twelve hauls were carried out in each area: 6 each of a square and diamond mesh codend (both 40 mm mesh size). A small mesh (20 mm) cover installed over the codends sampled catch escaping through the meshes.
(Summarised by: Chris Barrett)
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