The effect of grid size on catch efficiency and by-catch in the demersal trawl fishery for Norway pout (Trisopterus esmarkii)

Jesse Brinkhof*, Eduardo Grimaldo, Bent Herrmann, Hermann Pettersen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

91 Downloads (Pure)

Abstract

Norway pout (Trisopterus esmarkii) is caught with large trawls with small meshed codends, inevitably causing the fishery to have large by-catch issues. To reduce the amount of by-catch, a rigid sorting grid was made compulsory in 2010. However, there is still a severe by-catch issue, as well as the loss of target species because of the grid. A possible cause might be clogging of the grid, which could be solved by increasing the grid area. Therefore, this study compared the size selectivity of by-catch species and target species in a double-trawl configuration in which one trawl was equipped with a standard grid (6.30 m2), and the other trawl was equipped with a grid that had a 50% larger surface area (9.45 m2). The results demonstrated that the size selectivity and catch efficiency of the target species were unaffected; neither was there any significant difference between the two grids in terms of wanted by-catch species [blue whiting (Micromesistius poutassou), horse mackerel (Trachurus trachurus), and greater argentine (Argentina silus)]. However, the larger grid caught significantly more unwanted by-catch species [haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), and hake (Merluccius merluccius)]. Approximately one-third of the accumulated catches comprised the target species, one-third of wanted by-catch species, and one-third of unwanted by-catch species, demonstrating the by-catch challenges in this fishery. Simultaneously, none of the by-catch limits were exceeded.
Original languageEnglish
Article number106333
JournalOcean & Coastal Management
Volume229
Number of pages9
ISSN0964-5691
DOIs
Publication statusPublished - 2022

Keywords

  • Norway pout
  • Small-meshed trawls
  • Selectivity
  • Grid
  • Mixed fishery

Fingerprint

Dive into the research topics of 'The effect of grid size on catch efficiency and by-catch in the demersal trawl fishery for Norway pout (Trisopterus esmarkii)'. Together they form a unique fingerprint.

Cite this