Can a square-mesh panel inserted in front of the codend improve the exploitation pattern in Mediterranean bottom trawl fisheries?

Published source details Brčić J., Herrmann B. & Sala A. (2016) Can a square-mesh panel inserted in front of the codend improve the exploitation pattern in Mediterranean bottom trawl fisheries?. Fisheries Research, 183, 13-18.
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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 study (year not stated) of a seabed area in the Tyrrhenian Sea, Italy (Brčić et al. 2016) reported that fitting a square mesh escape panel to a bottom trawl net allowed only a small proportion of the undersized and non-target fish to escape capture. Data were not tested for statistical significance. For four of four fish species (target: Atlantic horse mackerel Trachurus trachurus, European hake Merluccius merluccius, red mullet Mullus barbatus; non-target: poor cod Trisopterus minutus capelanus) total percentage escape of fish through the square mesh was 0.8–5.3%. For fish below the minimum landing size, a total of 8.6% horse mackerel, 0.9% hake and 7.7% of red mullet escaped through the panel, representing 9.1, 1.3 and 25.0% for mackerel, hake and red mullet respectively, of the total escape of undersized individuals (panel and codend combined). Losses of marketable sizes through the panel were 0.5% for horse mackerel, 0% for hake and 0.9% for red mullet. A standard commercial Italian trawl net was fitted with a 50 mm square-mesh panel in the top of the final tapered section trawl body, 8 m in front of the codend. The codend was 6 m long and 50 mm diamond mesh. Eight trawl deployments were carried out (sampling times/year unspecified). Small-mesh (20 mm) covers installed over the square mesh panel and codend collected the escaping individuals. Both the cover and codend catches were weighed and sorted and the length of the three target fish species measured to the nearest 0.5 cm.

(Summarised by: Leo Clarke)