The effects of Nordmøre-grid bar spacings on catches in a Brazilian artisanal shrimp fishery

As part of attempts to improve and promote acceptance of the Nordmøre-grid in a Brazilian artisanal penaeid canoe-trawl fishery, the effects of bar spaces on the catches of key teleosts and crustaceans were investigated. Compared to a traditional codend, three Nordmøre-grids comprising 24-, 20- and 17-mm bar spaces, respectively, significantly and incrementally reduced the total weight of unwanted brachyurids (by 75, 95 and 97%), without affecting the catches of targeted seabob shrimp (Xiphopenaeus kroyeri). The various grids had few significant impacts on the catches of any teleosts; attributed to their small sizes and species-specific differences in behavioural responses. The results confirm the utility of the Nordmøre-grid for addressing a key bycatch concern among local fishers, and provide insight into ongoing development of appropriate modifications to improve selectivity in this, and other regional fisheries.

► We tested the effects of Nordmøre-grid bar spaces (24, 20, 17 mm) on bycatch species.
► Nordmøre-grids significantly and incrementally reduced the total weight of brachyurids.
► Grids had few significant impacts on the catches of teleosts.
► Catches of the targeted seabob shrimp were not affected.