|Reducing the benthos by-catch in flatfish beam trawling by means of technical modifications|In: Fisheries Research. Elsevier: Amsterdam. ISSN 0165-7836; e-ISSN 1872-6763, meer
beam trawl; benthos; by-catch; selective devices; square mesh window
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In the flatfish beam trawl fisheries the by-catch by weight of invertebrates is several times the amount of marketable fish. In order to reduce the impact of beam trawling on the benthic communities, a number of benthos escape modifications to the trawl were tested. A drop-out opening (escape zone without netting) and large diamond and square mesh escape zones just behind the groundrope were not effective in releasing the benthos by-catch and induced an unacceptable decrease in commercial catch. Square mesh windows inserted in the belly just in front of the cod-end were more promising. With these devices a significant reduction in weight and number of most benthic species could be realised. The penalty is some loss of commercial catch but the results indicate that with an appropriate mesh size in the square mesh window, a balance may be found between a significant benthos by-catch reduction and an acceptable loss of marketable fish.