Over the past few decades, environmental issues in coastal areas have acquired an ever-greater importance. Coastal environments provide the setting in which new conflictual relationships between different economic uses (transport, manufacturing, fishing, aquaculture, tourism, outdoor recreation, etc.) take place. At the same time there is broad recognition of the important role that coastal ecosystems, in particular wetlands and other shallow estuarine and coastal habitats, play in providing and maintaining biodiversity and productivity (Pinder and Witherick 1990).