The Gironde estuary is the last Western European estuary where all diadromous fish still migrate. In addition, the Gironde-Garonne-Dordogne basin is the last system known where the production of the Atlantic sturgeon takes place. The Gironde estuary is an essential habitat for the completion of the life history of this diadromous species. A European recovery plan launched in 1994 has shown the significance of the estuary for feeding and acclimatization of juveniles before their first journey to the sea. The Atlantic sturgeon has been threatened in the last 50 years, mostly by gravel extraction in spawning grounds and unadapted fishing regulations that have hed to overfishing. Since the end of the 19th century, several measures connected to navigation have been carried out in the Gironde estuary. This estuary, although only industrialised to a slight extent, has suffered from dredging since the creation of the navigation channel in 1875. Although gravel extraction is commonly recognised as causing serious damage to fish habitats, new gravel extraction projects in the Gironde estuary are under consideration. A qualitative risk factor analysis, based on the latest knowledge on the biology and ecology of the Atlantic sturgeon, shows that these projects lead to maximum risk for the survival of this species. Taking into account the present fragility of the sturgeon population, protective measures must be taken as a precaution. These would rule out any further gravel extraction;