Benthos Release Panel
A Benthos or Benthic release panel is a panel of larger diamond mesh or square mesh netting fitted into the lower panel of a trawl, usually a beam trawl to release benthic material, seabed debris and immature fish before they pass into the cod end.
This panel is designed to allow small seabed-living creatures escape through the square mesh panel fitted in the lower panel of the beam trawl. It is a 'riddling' mechanism rather than any escape stimulus by the animals that allows them to escape very soon after entering the trawl.
It also releases much of the sand and small stones thereby maintaining the retained catch in better condition in the cod end. The amount and size of creatures released is dependant on the size and orientation of the square mesh or large diamond mesh used as release panel. The size of this mesh has to be finely tuned to release as much of the unwanted benthos as possible without loss of marketable catch
It is accepted that benthos release panels have the capacity to release large amounts of unwanted benthos and debris. This in turn decreases the unnecessary mortality on these animals and makes the on board sorting of catches much easier.
If the mesh size is set correctly, benthos release panels will also release most of the undersized bottom living species that enter the trawl. Thereby helping to address the landing obligation that the vessels have to adhere to.
In some counties they have been experimenting with fitting electronics to emit pulses of electricity around of the benthos release panel to help stimulate the larger fish away from it.
The use of benthos release panels is encouraged in many European Beam trawl fisheries.