Evaluating a large-mesh belly window to reduce bycatch in silver hake (Merluccius bilinearis) trawls

  • Published source details Bayse S.M., Rillahan C.B., Jones N.F., Balzano V. & He P. (2016) Evaluating a large-mesh belly window to reduce bycatch in silver hake (Merluccius bilinearis) trawls. Fisheries Research, 174, 1-9.


This study is summarised as evidence for the following.

Action Category

Fit mesh escape panels/windows to a trawl net

Action Link
Marine Fish Conservation
  1. Fit mesh escape panels/windows to a trawl net

    A replicated, controlled study in 2011–2012 of a seabed area in the Gulf of Maine, USA (Bayse et al. 2016) found that fitting a large diamond-mesh escape window to a groundfish trawl net reduced the unwanted catch of one of seven non-target fish species/groups compared to a conventional small-mesh trawl. Catch rate of one of seven non-target fish species/groups (see original paper for species individual data) was reduced by 24% using the escape window (with: 1.4 kg/ha, without: 1.8 kg/ha) but was similar for six (with: 0.3–1.3 kg/ha, without: 0.3–1.4 kg/ha). The catch rate of the target species, silver hake Merluccius bilinearis, was similar with and without the window (with: 33 kg/ha, without: 38 kg/ha). In November 2011 to January 2012, a total of 58 alternating trawl deployments were made of a conventional silver hake trawl net fished either with a large diamond mesh escape window or as an unmodified conventional trawl net. Trawl designs were alternated via the addition or removal of a small-mesh panel zipped over the large mesh window. The escape window was 5 × 7 m large diamond mesh (330 mm) inserted in the lower panel of the trawl near the codend. The trawl net was small-mesh (50 mm) and equipped with a mandatory Nordmøre-type escape grid of 50 mm bar spacings. All catch was sorted and weighed for each tow.

    (Summarised by: Leo Clarke)

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