A device for reducing the catch of unwanted species of organisms in fishing trawls which allows the retention of shrimp and the escape of fish from the trawl. The device features a longer, smaller diameter cylinder nested within a shorter, larger diameter cylinder in such a way as to create a continuous escape opening around the entire circumference of the net. The trawl bag is attached to the downstream end of the outer cylinder and the trawl body is attached to the upstream end of the inner cylinder. Flow blocking plates, set at an approximate 45.degree. angle ahead of the escape opening, create an area of reduced water flow in and around the escape opening. Fish naturally move into the slower water flow and into the escape opening. Fish then move out of the trawl. Shrimp, being weaker in their swimming abilities are unable to move into the slower water areas and are therefore carried into the trawl bag and are captured.