Square mesh panels in demersal trawls: further data relating haddock and whiting selectivity to panel position

Published source details Graham N., Kynoch R.J. & Fryer R.J. (2003) Square mesh panels in demersal trawls: further data relating haddock and whiting selectivity to panel position. Fisheries Research, 62, 361-375.
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This study is summarised as evidence for the following.

	Action	Category
	Modify the configuration of a mesh escape panel/window in a trawl net Action Link

Modify the configuration of a mesh escape panel/window in a trawl net

A replicated, controlled study in 2000 of an offshore seabed area in the North Sea, Scotland, UK (Graham et al. 2003) found that changing the position of a square mesh escape panel in a trawl net improved haddock Melanogrammus aeglefinus and whiting Merlangius merlangus selectivity. The length at which haddock and whiting had a 50% chance of escaping was larger in nets with a square mesh panel located nearest (3–6 m) to the bag of the codend (haddock: 28.2 cm, whiting: 29.4 cm) than when the panel was located further away , (haddock, 6–9 m: 25.1 cm, 9–12 m: 25.5 cm; whiting, 6–9 m: 26.0 cm, 9–12 m: 27.1 cm) or when not using a panel (haddock:, 23.4 cm; whiting:, 25.0 cm). In August 2000, a twin trawl net was deployed with an experimental net on one side and a small-mesh codend net on the other, towed simultaneously. Nine experimental deployments were carried out with a square mesh panel 3–6 m from the cod-line, six with the panel 6–9 m from the cod-line, eight with the panel 9–12 m from the cod-line and nine without a panel. All codends were 100 mm diamond mesh and 100 mesh circumference. Panels were 3 m long with 90 mm square mesh. Fishing took place in the Buchan Deeps in depths of 68–106 m with tow durations of 2.0–3.5 hours. Fish were identified and lengths measured.

(Summarised by: Chris Barrett)