Overall, oceans and seas contain more biological diversity than terrestrial and freshwater ecosystems. Marine ecosystems play a key role in climate and weather patterns. Indispensable to life itself, the marine environment is also a great contributor to economic prosperity, social well-being and quality of life.

In light of the increasing concerns in relation to the state of Europe’s oceans and seas, the EU’s 6th Environment Action Programme included a commitment to develop a Thematic Strategy for the protection and conservation of the marine environment with the overall aim "to promote sustainable use of the seas and conserve marine ecosystems".

The need for such a policy stems from the economic, social, and environmental importance of the maritime dimension in Europe, as underlined in the Commission Strategic objectives for 2005-2009. The vision is that of a Europe with a dynamic maritime economy in harmony with the marine environment supported by excellence in marine science.

(COMMUNICATION FROM THE COMMISSION TO THE COUNCIL AND THE EUROPEAN PARLIAMENT, Thematic Strategy on the Protection and Conservation of the Marine Environment, COM(2005)504 final, Brussels 24-10-2005).