Could a T90 mesh codend improve selectivity in the Belgian beam trawl fishery?

  • Published source details Bayse S.M., Herrmann B., Lenoir H., Depestele J., Polet H., Vanderperren E. & Verschueren B. (2016) Could a T90 mesh codend improve selectivity in the Belgian beam trawl fishery?. Fisheries Research, 174, 201-209.


This study is summarised as evidence for the following.

Action Category

Rotate the orientation of diamond mesh in a trawl net

Action Link
Marine Fish Conservation
  1. Rotate the orientation of diamond mesh in a trawl net

    A replicated, paired, controlled study in 2006 of two fished seabed sites in the southern North Sea off Belgium and England, UK (Bayse et al. 2016) found that turning the diamond shaped mesh in the codends of beam trawls by 90° increased the size selectivity of two round-bodied fish species, but not of three flatfish species, compared to standard beam trawl codends. The lengths at which fish had a 50% chance of escaping were greater in turned diamond mesh codends for two round-bodied fish: whiting Merlangius merlangus (turned: 26 cm, standard: 12 cm) and pouting Trisopterus luscus (turned: 19 cm, standard: 11 cm); and for flatfish, they were similar for dab Limanda limanda (turned: 14 cm, standard: 14 cm) and plaice Pleuronectes platessa (turned: 13 cm, standard: 14 cm) and lower for sole Solea solea (turned: 19 cm, standard: 20 cm). By size class, all lengths of whiting and pouting larger than 10 cm had higher size selectivity in turned diamond mesh codends, while dab, plaice and sole larger than 16, 15 and 19 cm, respectively, had lower selectivity (data reported as selection curves). Trials were done by research vessel in January 2006 on fishing grounds along the Belgian coast and in the outer Thames Estuary off England. Data was collected from 15 deployments of two 4 m beam trawls towed side by side, each with a different codend: one with the netting orientation turned by 90°, and the other a traditional diamond mesh orientation (both 80 mm mesh size; see original paper for specifications). Covers attached over each codend collected escaped fish. Lengths of fish captured in the codends and covers were measured (sub-sampled when numbers were very high).

    (Summarised by: Chris Barrett)

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