Study

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.

Actions

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)

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 21

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust