ABSTRACT
Worldwide pressures from human activities have affected ecosystem health and their ability to perform essential functions to support human well-being on a long term basis and maintain sustainable development. There major environmental concerns about the marine environment such as overfishing, habitat modification, chemical pollution and eutrophication. Eutrophication is a serious threat especially on a long term basis because it affects almost all aspects of ecosystem functioning. It is also having many transboundary impacts in Europe, Central Asia and Northeast Asia. Unmanaged disposal of sewage from coastal cities, river discharges, agricultural runoff and the tremendous growth of fish culture especially in several East Asian regions are the main sources of the problem. The extreme phase of eutrophication that is oxygen-depleted zones is now present in the Baltic Sea, the Black Sea but also in many other coastal areas where fishery activities have been intensified. Harmful algal blooms are now widespread and fairly often dominated by toxic algal species especially in Asian and African coastal areas. In the present chapter the problem of eutrophication in the main regional seas is assessed and the effectiveness of the measures is discussed.
