The use of square mesh codends in the Icelandic shrimp (Pandalus borealis) fishery

  • Published source details Thorsteinsson G. (1992) The use of square mesh codends in the Icelandic shrimp (Pandalus borealis) fishery. Fisheries Research, 13, 255-266.


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, paired, controlled study in 1988–1990 of a bottom fishing ground in the Greenland Sea, north Iceland (Thorsteinsson 1992) reported that shrimp trawl nets with square mesh codends caught less small, unwanted fish than conventional diamond mesh codends. Data were not statistically tested. In two of two comparisons, catch rates of fish aged <1 year were lower in square mesh than diamond mesh codends for Atlantic cod Gadus morhua (square: 2–8 fish/ha, diamond: 6–130 fish/ha) and whiting Merlangius merlangus (square: 4–376 fish/ha, diamond: 27–2,472 fish/ha), and in one case for haddock Melanogrammus aeglefinus (square: 0–457 fish/ha, diamond: 0–1,245 fish/ha). Catches of one- and two-year-old fish were low but were typically lower in square mesh codends (see paper for data). Overall capelin Mallotus villosus catch rates (all ages) were lower in square mesh codends in two of two cases (square: 133–284, diamond: 842–1,104 fish/ha). Target shrimp Pandalus borealis catches were lower in square than diamond mesh codends in three of three comparisons. In 1988 and 1990, catches were compared between square mesh codends (36–37 mm) and conventional diamond mesh codends (36–40 mm) in 11 deployments of the two trawl net types towed side by side for 1 h.

    (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