Relative efficiency of square-mesh codends in an artisanal fishery in southern Brazil

the relative efficiency of two square-mesh codend designs with the same circumference (~2 m) but different mesh sizes and materials (32 mm polyethylene-pe and 30 mm polyamide-pa) was tested in an artisanal shrimp trawl fishery in paraná, southern brazil. the two square-mesh codends were hauled alternately with a 26 mm diamond-shaped mesh codend (control) in a twin gear configuration. although not significant, the mean numbers of total bycatch were reduced by 16.6 and 10.0% with the 32 and 30 mm square-mesh codends, respectively. the results indicate significant improvement in size selectivity for some species (xiphopenaeus kroyeri and stellifer rastrifer). the operational changes tested can be a suitable technical solution for reducing the capture of immature organisms in the shrimp trawl fishery in paraná, brazil.