Turtle excluder devices (TEDs) explained
See also: 
on this page:
- Commercial trawl nets
- How TEDs work in a trawl net
- TEDs and the law
- TED and bycatch reduction device (BRD) research links
Commercial trawl nets
Trawl nets (see figure 1 below) are used to catch prawns and scallops in northern Australia. Unfortunately, trawl nets also catch a wide variety and sometimes large quantity of unwanted species. Sea turtles, sting rays and sharks can also be incidentally caught in the trawl net. TEDs have been developed to reduce the capture of turtles and other large non-target species in commercial trawl nets.
The Pacific Ridley turtle pictured above was caught
in a trawl net and released uharmed.
Figure 1. Diagrammatic representation of
a trawl net
How TEDs work in a trawl net
Turtle Excluder Devices (TEDs) are a modification to the trawl net that allow larger animals to escape after being taken into the net, as it is difficult to prevent or reduce the number of unwanted bycatch animals that enter the trawl net in the first instance.
TEDs are usually fitted into a trawl net at the beginning of the codend (see figure 2 below). At this point in the net, water-flow is fastest and maximises the ability of a TED to separate target animals, such as prawns and scallops, from non-target animals, such as sea turtles.
Figure 2. Diagrammatic representation
of a Turtle Excluder Device fitted to a trawl net
Trawl net in a flume testing tank
showing a bottom opening TED.
TED fitted in a trawl net
TEDs usually include a metal grid, much like a storm-water-drain grate (hard TEDs) or a panel of large mesh webbing (soft TEDs) that is installed at an angle between 40° and 60°. This creates a physical barrier that allows prawns and other animals smaller than the bar spacing of a hard TED or mesh webbing of a soft TED to pass through the TED and into the codend. Sea turtles, other large animals and debris slide along the TED to an exit hole cut in the top (top opening TED) or bottom of the TED (bottom opening TED). The exit hole may be partially covered by a flap of webbing to reduce the possibility of losing prawns.
TEDs come in many designs and like other fishing gear, no single design of TED is suitable for all fishing conditions. When working properly, catch loss associated with these devices should be minimal, with indications that they may improve the quality or the quantity of the prawn catch in certain circumstances. Under poor conditions, these devices may cause major losses in prawn catch.
TEDs and the law
The mandatory use of TEDs is helping to prevent sea turtles from being caught in Australian trawl fisheries. TEDs have been made compulsory in the following trawl fisheries of Australia:
- Queensland East Coast Trawl Fishery daytime and inshore trawling (from January 2000)
- Northern Prawn Fishery (Gulf of Carpentaria, Arnhem land coast and Joseph Bonaparte Gulf) (from April 2000)
- Torres Strait Prawn Fishery (from March 2001)
- Queensland East Coast Trawl Fishery - all areas except river beam trawl (from January 2002)
- Other trawl fisheries in Australia (i.e., in South Australia and Western Australia) have also made TEDs compulsory in their prawn-trawl fisheries.
TED and bycatch reduction device (BRD) research links
Further information about TED and BRD research can be obtained from the following places:
Australian Research Centres:
- Australian Maritime College
- NSW Fisheries Research Institute
- Northern Territory Dept of Primary Industries and Fisheries
- South Australian Research and Development Institute
- Fisheries Department of WA
Overseas agencies:
- Turtle Excluder Devices (TEDS), National Marine Fisheries Service, Southeast Fisheries Science Centre, MS, USA
- University of Georgia Sea Grant , Marine Extension Service, GA ,USA
Page last updated 17 August 2006
