The effects of different cod-end design on bottom trawl selectivity in Turkish fisheries of the Aegean Sea

Published source details Lök A., Tokaç A., Tosunoğlu Z., Metin C. & Ferro R.S.T. (1997) The effects of different cod-end design on bottom trawl selectivity in Turkish fisheries of the Aegean Sea. Fisheries Research, 32, 149-156.
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This study is summarised as evidence for the following.

	Action	Category
	Modify the design or configuration of trawl gear (mixed measures) Action Link

Modify the design or configuration of trawl gear (mixed measures)

A replicated, controlled study in 1994 of an area of seabed in the Mediterranean Sea, off Turkey (Lök et al. 1997) found that two different trawl codend designs increased the size selectivity of red mullet Mullus barbatus compared to a standard codend, but there were no differences between codend types for annular seabream Diplodus annularis. The length at which red mullet had a 50% chance of escape was higher in both a ‘shortened lastridge rope’ codend (15.1cm) and a narrowed circumference codend (14.3 cm) compared to the standard (13.7 cm). For annular seabream, the 50% selection length was similar between all codends (short rope: 9.8 cm, narrow: 10.1 cm, standard: 9.9 cm). Data were collected in June and September 1994 in the Aegean Sea, from 40 trawl deployments (40–100 m depth, 50–60 min) of three different codend types: a roped codend rigged onto shortened ropes along each seam (14 hauls), a codend with the circumference reduced to 120 from 150 meshes (12 hauls), and a standard codend of 44 mm diamond mesh and 150 mesh circumference (see original paper for gear specifications). Small mesh covers attached over the codends sampled escaped fish. Codend and cover catches were sampled, and fish (fork) length recorded.

(Summarised by: Chris Barrett)