Assessment of relative performance of a square-mesh codend design across multiple vessels in a demersal trawl fishery

  • Published source details Macbeth W.G., Millar R.B., Johnson D.D., Gray C.A., Keech R.S. & Collins D. (2012) Assessment of relative performance of a square-mesh codend design across multiple vessels in a demersal trawl fishery. Fisheries Research, 134-136, 29-41.


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 (year not stated) of a fished area of seabed in the Tasman Sea, Australia (Macbeth et al. 2012) found that a square mesh codend reduced the amounts of discarded total catch (fish and invertebrates) in two target prawn trawl fisheries compared to commercial diamond mesh codends, and the effect on individual categories of discarded fish catch varied between species or the target fishery. Overall numbers of total discarded catch (fish and invertebrates) were reduced by the square mesh codend in both target prawn fisheries, by 48% and 77% (square: 69–382 ind/h, diamond: 287–661 ind/h). For the eastern king prawn Melicertus plebejus fishery, unwanted or undersized catches by number of three of the seven main discarded fish species/categories were reduced in the square mesh codend (by 59–95%), one was higher, and the rest were similar between square and diamond mesh codends. In the fishery targeting school prawns Metapenaeus macleaya, unwanted fish catch of four of the six main discard species/categories were 84–99% lower in the square mesh codend, while there was no difference for the other two between codend types (see paper for individual data). Catch data were collected by observers on seven commercial prawn trawlers operating from four ports off New South Wales: from 42 paired deployments targeting eastern king prawns (41–68 m depth) and 13 targeting school prawns (6–10 m). Each vessel was supplied with a 35 mm square mesh codend with a composite square mesh escape panel to test against the different diamond mesh codends (each with industry-designed square mesh escape panels) being used on each vessel (see paper for gear details). The square mesh codend was towed simultaneously with the industry standard codend on the outer trawls of standard triple-gear trawl configurations. The year the study took place was not reported.

    (Summarised by: Khatija Alliji)

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