A year-long trial of a square mesh panel in a commercial demersal trawl

Published source details Bullough L.W., Napier I.R., Laurenson C.H., Riley D., Fryer R.J., Ferro R.S.T. & Kynoch R.J. (2007) A year-long trial of a square mesh panel in a commercial demersal trawl. Fisheries Research, 83, 105-112.
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This study is summarised as evidence for the following.

	Action	Category
	Fit mesh escape panels/windows to a trawl net Action Link

Fit mesh escape panels/windows to a trawl net

A replicated, paired, controlled study in 1999–2000 of a seabed area in the North Sea off Shetland, UK (Bullough et al. 2007) found that fitting a square mesh escape panel to a bottom trawl net reduced the catch of unwanted, small whiting Merlangius merlangus, but not Atlantic cod Gadus morhua, haddock Melanogrammus aeglefinus or monkfish Lophius piscatorius, compared to a net with no panel. The average catch rates of whiting below minimum landing size (27 cm) were reduced by 34% with a panel (with: 6.4 fish/h, without: 9.4 fish/h) and catches of undersized cod ≤35 cm (with: 3.4 fish/h, without: 3.2 fish/hr), haddock ≤30 cm (with: 80.0 fish/h, without: 77.0 fish/hr) and monkfish ≤34 (with: 3.2 fish/h, without: 3.0 fish/hr) were similar. In addition, catches of some commercial sizes of whiting and cod were reduced by 10–41%. Data were collected from a total of 172 deployments of a 100 mm diamond mesh codend fitted with a 90 mm mesh square mesh panel, 6–9 m from the codend and an identical cod-end with no panel, attached to the same net (see paper for specifications). Codends were alternated every 24 h and tows were 2.5–6.0 h. Codend catches were sorted and all haddock, whiting, cod and monkfish were counted, and total length measured.

(Summarised by: Chris Barrett)