Coastal areas are among the most sensitive and most precious areas on the planet Earth. 20 percent of the world's population live in the 25 km distance and 39 percent live in the 100 km from the sea. It is expected that by the year 2025 this figure will be close to two third of the world population (Pruett & Cimino, 2000).
The economical importance of the sea and coastal areas are because of ports, shipping of goods, fisheries, oil and gas reserves, etc. which do not need explanation. For example, 11.8 percent of the oil and 25 percent of the gas reserves of the world are located in the coastal areas. the World Resource Institute (1995)an estimated the coastal ecosystems around the world to be worth 12x1012 $, while the total value of the global products per year are estimated to be around 33x1012 $ (Costanza et al, 1997). The environmental importance of the coastal areas are due to the existence of a very large diversity in marine and terrestrial biotypes along the protected habitats at the coastal zone such as coral reefs, mangrove forests, see grass, etc. On the other hand, the political and strategic issues related to the sea and the coastal areas have increased the importance of these areas. Fisheries and sea food are other important aspects of the sea because they have always been among the main sources of nutrition of the human being.
Despite all the important issues mentioned above, the 20th century has been witnessing the gradual deterioration of the natural resources, increase in the amount of pollution, and different kinds of over-exploitations that endangered the coastal areas.