Preliminary Tests of a Shrimp-fish Separator Section for Use in Shrimp Trawls

Abstract

A prototype shrimp-fish separator to be installed between the body and codend of a shrimp trawl was designed and constructed. The separator uses large square meshes to provide an escape path for fish, while funnels constructed of small mesh webbing keep the shrimp away from the big meshes and act as leading panels to guide the fish out of the trawl. A prototype was installed in the cut away after parts of a shrimp trawl, which was then mounted on an oval steel frame and towed just below the surface so that necessary adjustments could be identified and tested. After a satisfactory design had been developed, fishing trials were carried out in May, 1984, and further modifications to improve the separating efficiency were made. Preliminary analysis of this data shows that up to 61% of haddock less than 39 cm escaped, and up to 30% of cod less than 42 cm. Visual observations of a similar separating section were carried out with a remotely controlled underwater TV vehicle, and these are described.