Since 2001, an annual stock assessment of Manila (Ruditapes philippinarum) and European (Ruditapes decussatus) clams has been carried out in March in the Gulf of Morbihan and the Noyalo River. The objectives of this survey are: 1) estimate by direct assessment, the biomass of the stock and its geographical distribution; 2) estimate the exploitable biomass and exploitation potential for the sampled sites in particular, in areas reserved for professional fishing; 3) to establish a diagnosis, with a medium-term vision, on the state of the stock; 4) to propose the implementation of appropriate management measures.