To draw up an inventory of the "Western Channel" ecosystem by collecting complete data covering a maximum of compartments of this system (hydrology, planktonic compartments including fish eggs and larvae, benthic invertebrates, pelagic, demersal and benthic fish and cephalopods, birds and marine mammals). To determine the impact of climate change in the Channel on the composition of benthic invertebrate assemblages, the integrator group of these changes, through sampling of particular stations for which historical data exist. Carry out an intercalibration with the N/O Gwen Drez so that the CGFS (Channel Ground Fish Survey) data set can be continued on another vessel in the coming years.