Site details

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5 stars - Fully protected as a national park or Natura 2000 site by national legislation
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Extensive description of site:

The bay itself is around 20 km wide and this part of the gulf, the depth does not exceed 20 m. The area is characterized by a megatidal regime and benthic communities are distributed in response to hydrodynamic and sedimentary gradients from the coast to the open sea. Moreover, sedimentologists consider the bay as one of the most beautiful models of current sedimentation in the world. The bay is unique in Europe too for the extend of its intertidal zone : mudflats and salt marshes (240 km2). The bay has several important ecological functions : the bay is the most important area of the Channel and North Sea for many fishes and especially for flat fishes. The fishing activities concentrate not only on fishes but also on molluscs and crustaceans. The bay is also one of the most important for shellfish production and is a zone of international importance for wintering water birds, especially waders.

Habitats present:
Seagrass beds 

Description of fauna and flora:

The fauna and flora, especially invertebrates and plants of salt marshes, are well documented, and have been researches since the Marine Station of Dinard (MHHN) was opened in 1928.

Pristiness: High


Mont Saint-Michel and the surrounding bay are the only French world heritage site where both the architectural and natural aspects are listed as very important. The site is pristine with respect to both anthropogenic and natural stresses– relative to the conditions dominant in the region (moderate freshwater input, macrotidal regime)

Human impact:

The area is subjected to low levels of pollution but is one of the major French sites for shellfish farming (6000 tons of Oysters and 10000 tons of mussels per year). The Sabellaria alveolata reefs are locally impacted by various human activities (fishing, ecotourism etc.).


The proximity of the Marine Station of the “Muséum National d’Histoire Naturelle de Dinard” and the existence of national and international scientific programmes.

Available database and website:

The species inventory is available (books, reprints, reports etc.)

Commitment and ongoing research:

The Marine Station of Dinard belongs to the MARS Network and to the "Réseau National des Stations Marines" and is closely connected to the IFREMER Marine Station of Saint-Malo and to the Laboratory of littoral geomorphology and environment of Dinard (EPHE). The Staion is involved in the French National program of coastal environment (PNEC) and supervises environmental research conducted in the Bay.