Reduction of discards by technical modifications of beam trawls

B. van Marlen, A.T.M. van Helmond, E. Buyvoets

Research output: Book/ReportReportProfessional


Experiments were carried out in 2007 and 2008 on discard reducing techniques in flatfish beam trawling onboard FRV “Tridens” in close cooperation with the fishing industry. A total of 38 gear tests were conducted in which modified beam trawls were compared in pair with a conventional 12 m beam trawl. The modifications consisted of a T90 aft part and various Square Mesh Panels (SMPs) in the bottom sheet, top sheet and combinations of both, and variations of a Benthos Release Hole with a guiding V-panel in the bottom sheet. It was found that a panel in the bottom sheet with 160 mm mesh size appeared to perform best without releasing too many marketable fish. The panel should extend relatively far aft just in front of the codend here the netting is offground. Panels placed only in the top sheet are not very suitable in reducing benthos ycatches. In addition the Benthos Release Hole with guiding device seems to be effective in reducing such bycatches. The cooperation between fishermen and scientists worked very well and created better mutual understanding. Further work is advocated to optimise the design of these devices. It is expected that such devices will get wider application in the Dutch beam trawling sector.
Original languageEnglish
Place of PublicationIJmuiden
Number of pages69
Publication statusPublished - 2009

Publication series

NameReport / Wageningen IMARES
PublisherIMARES C003/09


  • fishery management
  • beam trawling
  • fishing gear
  • adverse effects
  • marine ecology
  • discards
  • reduction
  • innovations

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  • Cite this

    van Marlen, B., van Helmond, A. T. M., & Buyvoets, E. (2009). Reduction of discards by technical modifications of beam trawls. (Report / Wageningen IMARES; No. no. C003/09). IMARES.