The Site represents the largest natural estuary in northern France composed of vast sand, mudflats, and grassy areas. The exceptional character of the Site is reflected by its avifauna diversity with 365 bird species identified. Located at the confluence of migratory routes, the Site is one of the most important European resting and feeding areas for migrating waterbirds. It also provides a refuge during cold weather events, especially for waders and ducks. During the wintering period, the Site sustains over 1% of the individuals of the biogeographic population of the Northern pintail, Northern shoveller and common shelduck. The Site also supports 275 species of plants, including various rare species such as the fen orchid Liparis loeselii. Human activities include cattle grazing, hunting, commercial fishing, shellfish farming, and tourism. The "Maison Ramsar de la baie de Somme" is one of two study centres at the Site. The main threats to the ecological character of the Site relate to drainage, hunting, invasive species, pollution, and recreational and tourism activities. Silting up of the estuary is accelerating and will alter the food web in the estuary which will in turn become less suitable for migrating and wintering waders. All protected areas on the Site have a management plan and a site-specific management plan covering the whole Ramsar Site is in place for the period of 2014-2022.