The project presented here and named HydroPêche aims to develop a tool for an automatic optimisation of trawl in order to minimize the drag of the gear. For that purpose, different aspects are studied in order: a/ to extend the basis of experimental data on flow characteristics governing the hydrodynamic behaviour of different porous structures ; b/ to develop numerical tools to simulate more realistic flow around porous structures taking into account fluid / structure interactions; c/ to develop automatic optimisation tools to design efficient trawls in terms of energy consumption. The developed tool should provide a substantial gain on the fuel consumed of actual fishing devices while maintaining a comparable fishing efficiency. The developments made will also be extended to study different types of porous structures used for fishing and aquaculture devices and to better understand the development of selectivity devices. Initial results have been achieved: some specific data analysis was carried out from PIV measurements around a cod-end, FreeFem ++ has been used to simulate the flow around a specific cod-end and the first developments of an automatic optimisation tool give good numerical results in terms of energy efficiency for both bottom and pelagic trawls.Read less <