Grid devices to select shrimp size in trawls

Discard of small shrimps and fish is a substantial problem in the fishery for deepwater shrimp in the Northwest Atlantic. In order to solve this problem, different grid devices are under development to sort out discard sized shrimp and fish in the trawl. Successive experiments with three different grid devices were carried out at West Greenland in 1991 and 1992. The ability to sort out small shrimps increased during the trials. However, the most efficient device tested in 1992 also sorted out a great amount of the larger shrimp, making it unsuitable for the commercial fishery at this developmental stage. Small fish with a regular shape such as redfish were well separated by the grids, while flatfish as Greenland halibut were inefficiently sorted and gave rise to blocking of the grid. A future improvement of the grid is discussed in relation to operation and selection abilities