Lighter, stronger nets being tested in the waters off Brownsville could help Gulf shrimpers, who are forced to use turtle-excluder devices, keep more of what they catch, marine researchers say. But the nets, which cost 14 times more than what's commonly used now, may cost more than they are worth, shrimpers say. Every shrimp net is required to be equipped with a TED, which is a grid of bars that slant toward an opening at either the top or the bottom of the net. The grid is fitted into the neck of a shrimp trawl.
Shrimp slip through the bars and are caught in the trawl.
When larger animals such as turtles are caught in the trawl, they are pushed against the grid bars and can escape through the opening. But when mud or hard pieces of trash and debris in the ocean come through the net, they may knock the TED out of alignment and cause the shrimp to escape through the openings intended for the turtle and other bycatch. It has to be at a certain angle. Vessels in deep water encounter a lot of mud. A lot of pressure is placed on the grid and this changes angle of grid.