Trapdoor installed into trawl nets used by shrimp fisheries, allowing turtles caught in the net to escape easily without impairing the performance of the net.It consists of a grid of bars with an opening either at the top or the bottom of the trawl net. The grid is fitted into the neck of a shrimp trawl. Small animals such as shrimp pass through the bars and are caught in the bag end of the trawl. When larger animals, such as marine turtles and sharks are captured in the trawl they strike the grid bars and are ejected through the opening. Initial TED designs did not allow for the release of larger leatherback and hardshell turtles and TED openings were later redesigned to address this problem.