NourDem surveys consist of sampling in estuarine and coastal sectors using the GOV trawl (Large Vertical Opening) "Ifremer / NourDem 11.90-16.45m". This trawl is operated from small professional trawlers, about ten meters in length and less than 2 meters in draft, so as to be able to sample the most upstream sectors of the estuaries (down to zero of salinity), including the foreshore area at high tide, areas where nurseries for many species are located (case of sea bass Dicentrarchus labrax or sole, Solea solea, for example). When fishing, this trawl sweeps the seabed over a width of around 7m, and its vertical opening is between 2.20m and 2.40m. The objective of these campaigns is to produce annual abundance indices for the main species of the estuary, indices which are intended to be used: - or locally, by local managers (Marine Parks, GIP, Communities of municipalities, etc.) as part of their monitoring, preservation, information / popularization of knowledge missions, etc. - or by the working groups of the ICES (International Council for the Exploration of the Sea), in charge, on behalf of the European Union and the Member States, of the assessment of the state of exploited stocks and of development of management recommendations. The cruises last 8 days each, which allows the construction of around 70 trawl tows depending on the sector. The other objective is to be able to take samples for other research projects.