The effect of Nordmore grid length and angle on codend entry of bycatch fish species and shrimp catches

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Larsen, Roger B., Sistiaga, Manu, Herrmann, Bent, Brinkhof, Jesse, Tatone, Ivan, Santos, Juan
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: Text; article; ddc:570; Gadus morhua; northern shrimp; Pandalus borealis
• Online Access: https://doi.org/10.1139/cjfas-2018-0069; https://www.openagrar.de/receive/openagrar_mods_00051337; https://www.openagrar.de/servlets/MCRFileNodeServlet/openagrar_derivate_00023272/dn060720.pdf

The Nordmøre grid is regarded as an efficient bycatch-reducing device and is used in various shrimp trawl fisheries globally. However, in some shrimp fisheries, bycatch remains a problem that seriously impacts commercial trawl activities. This study tested and compared the performance of two versions of the Nordmøre grid in the northeast Arctic deepwater (northern) shrimp (Pandalus borealis) fishery, a standard version with an operating angle of approximately 45° and a longer version of the grid (40% longer) with an operating angle of approximately 30°. The grid passage probability for the bycatch of juvenile cod (Gadus morhua), haddock (Melanogrammus aeglefinus), American plaice (Hippoglossoides platessoides), and redfish (Sebastes spp.) increased significantly for certain size ranges of fish when using the longer grid. The longer grid also resulted in a significant increase in grid passage probability for large shrimp. Previous studies have reported that a reduced operating angle can lead to a lower grid passage probability for bycatch fish species and shrimp; however, the results of the current study demonstrate that a longer Nordmøre grid more than compensates for the reduced operational angle. La grille Nordmøre est considérée comme un dispositif de réduction des prises accessoires efficace et est utilisée dans diverses pêches au chalut à crevette à l’échelle planétaire. Dans certaines pêches à la crevette, les prises accessoires demeurent toutefois un problème qui a un important impact sur les activités de pêche commerciale au chalut. L’étude a vérifié et comparé la performance de deux versions de la grille Nordmøre dans la pêche à la crevette nordique (Pandalus borealis) dans le nord-est de l’Arctique, soit une version standard à inclinaison opérationnelle d’environ 45° et une version plus longue (de 40 %) à inclinaison opérationnelle d’environ 30°. La probabilité de passage à travers la grille pour les prises accessoires de morues franches (Gadus morhua), d’aiglefins (Melanogrammus aeglefinus), de ...