Measurements at sea during fishing trials on bottom trawl have revealed that the geometry of the trawl is affected by the catch. A series of 37 hauls of around 3 h were carried out during the French EFFICHALUT project. The aim of this project was to carry out improvements on the fishing gear in order to reduce energy consumption. For this project, numerous sensors were used: for bridle tension, door spread, vertical opening, and door attitude. The measurements show quite clearly that the door spread decreases and the bridle tension increases during most of the hauls. The door spread decreased by 1.35 m/h, with a standard deviation of 1.98 m/h while the top bridle tension increased by 47 kg/h, with a standard deviation of 59 kg/h. The mean catch per haul... |