A system and method for sorting fish where the system comprises；—a trawl (2) consisting of at least one trawl bag (3,3′, 3″), and where the at least one trawl bag (3, 3′, 3″) has an opening which covers a part of an inflow area in the trawl (2),—at least one monitoring device (6) arranged in connection with the inflow area and where signals can be transmitted to a processing unit from the at least one monitoring device (6), and—where a device, based on data from the processing unit, can move the opening in the at least one trawl bag (3, 3′, 3″) to a position where fish flow through the inflow area but on the outside of the at least one trawl bag (3, 3′, 3″).
