Questioning the effectiveness of technical measures implemented by the Basque bottom otter trawl fleet: Implications under the EU landing obligation

Published source details Alzorriz N., Arregi L., Herrmann B., Sistiaga M., Casey J. & Poos J.J. (2016) Questioning the effectiveness of technical measures implemented by the Basque bottom otter trawl fleet: Implications under the EU landing obligation. Fisheries Research, 175, 116-126.
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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, controlled study in 2011 of bottom fishing grounds in the southern Bay of Biscay, France (Alzorriz et al. 2016) reported that bottom trawl nets fitted with square mesh escape panels did not increase the overall escape of undersized catch of three of three fish species, relative to those escaping from the codend. Data were not statistically tested. For fish under the minimum legal size that entered the net, the square mesh panel allowed 0.7% of hake Merluccius merluccius, 11.9% of poor cod Trisopterus minutus and 0.9% of striped red mullet Mullus surmuletus to escape, while 47.3% of undersized hake, 71.4% of undersized poor cod and 53.9% of undersized red mullet escaped through the meshes of the codend. Data was collected from 15 trawl deployments on a research survey in November-December 2011. A trawl codend of 70 mm diamond mesh fitted with one 100 mm square mesh panel located 13 m from the codend was tested (see paper for specifications). Covers installed over the panel and codend collected escaping fish. Fish in both the cover and codend were identified, counted and lengths measured.

(Summarised by: Leo Clarke)