Atlas thématique de l'environnement marin en baie de Saint-Brieuc (Côtes-d'Armor)

This atlas presents in a synthetic form the hydrodynamical, geological and biological characteristics of one of the most studied region of the French littoral. Geologic and geophysical data of the Saint-Brieuc Bay show that the deep basement consists of pre-palaeozoic or palaeozoic sedimentary series in the centre of the Bay, whereas metamorphic and magmatic formations are dominant in coastal regions. The location of superficial sediments in the Bay, is mainly due to marine currents. A granulometric gradient, from very fine to coarse sediments, appears in two directions: from the coast towards the high sea, and from the west to the east. Rocky substrates disrupt the sediment distribution, with, most of the time, a concentration of coarse sediments near the shoals. On these bottoms, the benthic macrofauna is mainly represented by bivalves, several species of which are exploited or potentially exploited (Pecten maximus, Venerupis rhomboides, Glycymeris glycymeris, Venus verrucosa). But the predominant species actually is Crepidula fornicata, a recently introduced gastropod mollusc, competing with commercial species. The biological diversity of the Bay has induced to carry on many and various professional fishing activities.