The Thau lagoon is situated in the Languedoc Roussillon region (South East of France), along The Mediterranean border. The Thau lagoon and its surroundings are recognized as sites of Communautary Interest, as an important conservation areas (ZNIEFF, ZICO, NATURA 2000), and the Canal du Midi which is connected to the Thau lagoon is part of world human patrimony (UNESCO).
The Thau lagoon has a surface of 75 km2 and an average depth of 4,5m (max : 10m.). It is under strong marine influence. The lagoon is connected north to the sea by the canal of Sète (90% of exchanges) and South by the Grau de Pisse Saumes. The volume of the lagoon is 280.000.000 m3. During a year a third of this volume is exported to the sea.
Main hydrological regime of rivers is intermittent, only one, the Vene has a permanent output. Precipitation show large interannual variation (from 200 to 1.000 mm per year). The population on the watershed reaches 107.000 inhabitants (density of 380 inhab.km2) with a very strong growing rate (75% on the last ten years), so urbanism are the problem in region.
Some of activities which doing in this area are Shelfish farming (more than 10% of the whole french production), fisheries (clams and fishes), Tourism and recreational activities (bathing, nautism), agriculture (wineyards), and marine industry (Sète harbour).
Most of activities are potentially as a cause of the environmental pressure. Some case are happened ie : Harmfull Algae bloom (PSP : Alexandrium and DSP : Dinophysis); bacteriological contaminations, anoxias, biodiversity changes, alien species (macroalgae), nutriment fluxes, trophic balance changes.
Much effort has been put into the setting up of a first integrated management programm (SMVM for Schema de Mise en Valeur de la Mer) which defines priorities of action about shelfish farming and offer a spatialised plan for the developpment of concurrential activities in the lagoon and on a part of the watershed. The main drawback of this SMVM (the first to be adopted in France) is its fixed frame which is difficult to make evoluting as decision for evolution/modification has to be taken at the summit of the French state (Conseil d’Etat). Other efforts have been put in works on the watershed (Two Contrats d’Etang) as to optimise waste water processing in relation with the occurrence of bacteriological contamination of lagoon waters and shellfish.
The Project will be setting up of a first integrated management plan (SMVM) with priority to shellfishculture activities in the lagoon.