The reserve is home to both harbor seals and the larger gray seal, which are often visible on the Banc de l'Ilette.
During peak migration, the bay supports over 300,000 individual birds, including avocets, spoonbills, and various plovers.
The Somme estuary possesses one of the strongest tidal ranges in the world, causing the sea to recede for several kilometers at low tide.
The 'mollières' or salt meadows within the reserve are grazed by the 'pré-salé' sheep, a local breed whose meat is prized for its unique flavor.
The reserve was officially established in 1994 to preserve the biodiversity of the estuary from intensive hunting and development pressure.
The National Nature Reserve of the Somme is the largest estuary in northern France, covering approximately 3,000 hectares of dunes, salt marshes, and mudflats. It is a critical habitat for migratory birds, serving as a key stopover point along the East Atlantic Flyway. The area hosts the largest colony of harbor seals in France, which can be observed resting on the sandbanks at low tide. The reserve is specifically managed to protect fragile coastal ecosystems from human impact. It features a network of trails and observation points designed to allow wildlife viewing without disturbing natural behaviors. The landscape undergoes drastic shifts throughout the day due to the Somme's powerful tidal range. It is integrated into the wider Baie de Somme, which is designated as a site of international importance under the Ramsar Convention.
The observation hides near the Maison de la Baie de Somme which offer elevated views over the mudflats.
Check official tide tables before arrival, as high tide covers most observation areas and access points.
Bring high-quality binoculars or a spotting scope, as wildlife is often located at a significant distance from designated paths.
Stay strictly on marked trails to avoid damaging sensitive salt marsh vegetation and to prevent scaring resting seals.
Attempting to cross the mudflats or sandbanks without a certified guide, as the incoming tide is extremely fast and hazardous.
Paths in sensitive zones may be restricted during peak breeding seasons; visitor centers generally operate with reduced accessibility in mid-winter.
Maintain a minimum distance of 300 meters from seal colonies; do not use drones; keep pets strictly on a leash or prohibited in core zones.
