Preliminary study on separator shrimp trawl in Dapeng Gulf

Shrimp trawls are characterized by various catch species and high discard ratio. There is little known about the species selectivity of shrimp trawl in the South China Sea. In order to improve the current status of the fisheries and protect the juvenile shrimp and fish resource, shrimp/fish separation experiments were conducted in Dapeng Gulf. Separator panels with different mesh size (130 and 110 mm) and mesh shape (diamond and square) were inserted into the foreside of the codends of shrimp trawl, which is named locally after butterfly trawl. Thus, the codend was divided into two levels: shrimp bag above and fish bag below. The separator ratios of shrimp were estimated. Additional, rigid TED was installed in the extension to improve the separator efficiency. It demonstrated that the shrimp individuals retained by the shrimp bag were larger than those retained by the fish bag. Comprison of separator ratio estimated with different separator panels, it's more for mesh size than for mesh shape, taking significant effect on the separator ratio. Therefore, separator ratios would increase with the installation of TED.