Study

Size selection by diamond- and square-mesh codends in multi-species Mediterranean demersal trawl fisheries

  • Published source details Sala A., Lucchetti A., Piccinetti C. & Ferretti M. (2008) Size selection by diamond- and square-mesh codends in multi-species Mediterranean demersal trawl fisheries. Fisheries Research, 93, 8-21

Actions

This study is summarised as evidence for the following.

Action Category

Use a square mesh instead of a diamond mesh codend in a trawl net

Action Link
Marine Fish Conservation
  1. Use a square mesh instead of a diamond mesh codend in a trawl net

    A replicated, controlled study in 2004 in one shallow inshore and one deeper offshore seabed area in the Adriatic Sea, Italy (Sala et al. 2008) found that for five roundfish species, but not one flatfish species, using a square mesh codend improved the size selectivity of a bottom trawl net compared with a diamond mesh codend. Overall, the length at which 50% of fish are predicted to escape was greater in the square mesh codend for European hake Merluccius merluccius (square: 14 cm, diamond: 8 cm), red mullet Mullus barbatus (square: 11 cm, diamond: 8 cm), common pandora Pagellus erythrinus (square: 10 cm, diamond: 8 cm), Mediterranean horse mackerel Trachurus mediterraneus (square: 13 cm, diamond: 10 cm) and poor cod Trisopterus minutus capelanus (square: 11 cm, diamond: 8 cm), but was lower for one flatfish, scaldfish Arnoglossus laterna (square: 8 cm, diamond: 8 cm). Fishing surveys were done by research vessel on two fishing grounds in the Central Adriatic: in August–September 2004 (15–21 m depth, 5nm off Ancona), and in September–October 2004 (70 m depth, Western Pomo pit). Two trawl codends with the same mesh size (38 mm) but different mesh configuration (square and diamond mesh) were fished daily and alternately on the same trawl for a total of 48 deployments (21 shallow, 27 deeper). A small mesh cover (20 mm) attached over each codend collected the escaping fish catch. Catches in both the codends and covers were sampled by species and fish total length.

Output references

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, terrestrial 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 18

Go to the CE Journal

Subscribe to our newsletter

Please add your details if you are interested in receiving updates from the Conservation Evidence team about new papers, synopses and opportunities.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust