It seldom corresponds to existing administrative or planning units. The natural coastal systems and the areas in which human activities involve the use of coastal resources may therefore extend well beyond the limit of territorial waters, and many kilometres inland. The natural habitats of the shoreline are very varied but also very small in area, and have been shrinking fast for several decades. Eight of the forty priority habitats listed in the Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora are coastal. Approximately a third of the Union's wetlands are located on the coast, as well as more than thirty per cent of the Special Protection Areas designated under the Directive on the Conservation of Wild Birds .
Coastal ecosystems tend to have very high biological productivity.
The reproduction and nursery grounds of most fish and shellfish species of economic value are in the coastal strip, and a significant proportion of the catch of these species comes from this area, which accounts for almost half of the jobs in the fisheries sector. The quality of coastal waters is a major cause for concern. The two most spectacular phenomena in recent years, oil slicks and algal blooms, are illustrations of the fact that coastal communities frequently suffer the consequences of events or developments occurring inland or offshore and therefore beyond their control. Human settlement of the coastal zones and utilisation of their natural resources since early times has created unique forms of rural and urban landscapes, reflecting cultures centred on trade and largely oriented towards the outside. Unfortunately, urbanisation and uniform agricultural and industrial developments have considerably reduced the biological diversity and cultural distinctness of the landscapes in most parts of Europe.