Fishing and Gear Technology

Unit 15 - Selectivity in fishing gear

15.1.By-catch reduction devices in trawl gear

In shrimp fisheries, much effort has been directed to improve selection performance of by-catch reduction devices in the trawl gears.
The first design consisted of larger mesh panel in the side panel of the trawl which guided the fish to escape outlet while shrimp passes through the mesh opening of the panel to the codend. The separator trawl was developed on this principle.
The recent by-catch reduction devices developed in Norway and Canada use a grid in the shrimp trawl. This system consists of a rectangular metallic grid slanting outward and upwards, placed in the aft belly in front of the codend (Fig.2) and a fish outlet on the top of the trawl in front of the grid.