One of the threats to endangered sea turtle species is the use of nets by commercial shrimp-fishing boats. When turtles get accidentally caught in the nets, they cannot rise to the surface of the ocean to breathe, and they die. Some people suggest that this problem can be solved through an invention called a turtle excluder device (TED) that is incorporated into the nets. A TED provides a passage through which the turtles can escape. However, TEDs have been criticized for several reasons.
First, some shrimpers (shrimp fishers) argue that turtles get trapped only rarely: it is estimated that on average, one shrimp boat accidentally catches about one turtle every month. On the other hand, using TEDs costs the shrimpers some of their catch. Every time the shrimpers cast the nets, a certain percentage of shrimp manage to escape through the turtle passages. The shrimpers complain that the cost of losing shrimp on a daily basis is too high in comparison with the small chance of saving one turtle.
Second, there are alternative methods of protecting sea turtles that may be more effective than TEDs. One method that can be used is shortening the time limit that shrimp boats are allowed to keep their nets underwater. When the time limit is reached, the nets have to be pulled up to the surface, allowing any turtles caught in the net to get air and also giving shrimpers the opportunity to release the turtles from the nets.
Third, TEDs are not effective for larger species of endangered sea turtles. Some species like loggerhead and leatherback turtles can grow to be quite large and cannot fit through the escape passage that standard TEDs provide. Such turtles cannot escape from the nets even if the nets are equipped with TEDs.