Essais d'un chalut avec fenêtre à mailles carrées en Mer du Nord

The fragile state of the cod stock in the North Sea and Western Scotland has made the European Commission take a certain amount of measures to reconstitute these stocks since the end of 2001. One of those measures consisted of improving the selection capacity of the bottom otter trawls in order to reduce the capture of juveniles, through a compulsory selection device of square mesh panel type. In this context, the Regional Marine Fisheries Committee of Nord/Pas-de-Calais/Picardie, which is against any increase of the mesh size but agrees with the adoption of a new selection device, decided to organize technical trials along with the IFREMER, so as to evaluate its efficiency. A square mesh panel system was tested in multispecific fisheries in the southern part of the North Sea. The aim was to check the compatibility of the device with the double demand of (1) letting as many cod juveniles escape as possible, and (2) catching enough market fish (including other species than cod) to maintain the job's profitability. A sea trial, with the help of a professional vessel, has quickly been set up, in order to test a system with three different technical configurations in the southern part of the North Sea (Ivc4). The escape of fishes was estimated using the double pack method. In spite of bad trial conditions, the two sea trials enabled us to gather interesting information about the escape of different species (and their size class), as well as to estimate the sales loss.