ABSTRACT
The Seine estuary is located at the mouth of a river basin that is highly populated and exposed to important pollutant inputs from industry and agriculture. These inputs are contaminating the food web. Le Havre harbor at the mouth of the estuary and Rouen harbor 80 km upstream generate important sea traffic that has required the fitting of dikes, the dredging of channels, and land reclamation to support ports and industry, changing drastically the morphology of the estuary. A decrease in intertidal area has accompanied these changes and mudflats have been progressively colonised by shore vegetation and brackish reed beds.
