Since the mid 80's, a tidal population of the polychaete Lanice conchilega has proliferated along the eastern part of the "Baie des Veys" (Western part of the Bay of Seine). Population density 7 000 individuals per square meter. This proliferation affected significantly the local oyster farming industry, by resulting increased sedimentation rates. This work try to improved understanding the phenomenon by analyzing at various temporal and spatial scales the ecosystem and its relationship with the Lanice conchilega population dynamics. Several field works were carried out (i.e. bottom type mapping, topography, hydrology) to analyse the occurrence and development of this population taking into account the overall changes of the "Baie des Veys" ecosystem.... |