|Equipment Class: Fishing technology||Equipment Type: Environmental measures|
|Turtle Excluder Device (TED) is a device fitted to a net or modification that allows turtles to escape immediatly after capture in the net. TEDs were originally designed to exclude the capture of turtle or other large animals in shrimp nets so as to lend protection to this endangered species from capture.|
TED: Rigid grid, the NAFTED (Turtle Excluder Devices). Click for more.
TEDs can be separated into two different groups, active and passive, depending on how bycatch is excluded. Active TEDs use fish behaviour to separate target from non target animals. These TEDs use windows (holes in the net with selvedged edges) and netting funnels to create escape routes for fish and rely upon natural escape responses of the non target animal. Passive TEDs use physical sorting method to separate target from non target animals. These TEDs are characterized by grids or panels of netting which physically restrict large animals from passing through. TEDs can also be separated into hard TEDs, which contain hard metallic components such as grids and wire, and soft TEDs which use soft components such as netting and rope. Single grid hard TEDs are most popular within the fishing fleet of the USA, followed by soft TEDs and hard TEDs. The efficiency of hard TEDs can be affected by bar spacing, the presence or absence of a flap, the length of the flap, the presence or absence of a funnel, the installation angle and wether it is a top excluder or bottom excluder. Similarly, soft TED performance can be affected by mesh size, presence or absence of a flap, correct installation, whether it is a top or bottom excluder and its design at the apex. Optimum Grid angle for all types of TEDs is between 40 to 60 degrees. There are several models of the turtle excluder devices. The most common is the NAFTED which consists of two oblong end hoops holding a diagonal deflector grid that are sewn into the trawl net ahead of the codend. The devices has a top-opening door.