The Mediterranean, a semi-enclosed sea
The Convention of 1982 consecrates the notion of an enclosed or semi-enclosed sea, giving their definition  in descriptive and geographic terms which require no particular legal interpretation. The definition is based on four physical factors:
— a sea surrounded by two or more States,
— a sea connected to another sea or the ocean,
— by a narrow outlet (straits),
The semi-enclosed Mediterranean Sea conforms to this geographical description, and, with the exception of the Area, all the categories of areas created by the Convention can apply to it.
However, the Mediterranean has a special past which has created a distance, over the decades, between areas under sovereignty or national jurisdiction (cf. the EEZ and the Mediterranean*).
Yet this particular feature distinguishing the Mediterranean also explains the origins of the appearance of maritime areas not covered by the United Nations Convention on the Law of the Sea of 1982: its very nature as a semi-enclosed sea has led to reflection on legal regimes under which the rights of coastal States can be exercised (cf. Offshoots of the EEZ).
In fact, article 123  of the Convention introduces the idea that the unilateral nature of national jurisdiction should be tempered by the feeling of a shared heritage, giving rise to cooperation among the States bordering the Mediterranean Sea.
Cooperation of States bordering enclosed or semi-enclosed seas
States bordering an enclosed or semi-enclosed sea should cooperate with each other in the exercise of their rights and in the performance of their duties under this Convention. To this end they shall endeavour, directly or through an appropriate regional organization:
a) to coordinate the management, conservation, exploration and exploitation of the living resources of the sea;
b) to coordinate the implementation of their rights and duties with respect to the protection and preservation of the marine environment;
c) to coordinate their scientific research policies and undertake where appropriate joint programmes of scientific research in the area;
d) to invite, as appropriate, other interested States or international organizations to cooperate with them in furtherance of the provisions of this article.
This article 123 is, in itself, a synthesis of governance relying on cooperation among coastal States. Cooperation is here both a goal and a mechanism. It encompasses both the exercise of rights and the fulfilment of obligations. A place is given to appropriate regional organizations. The main activities of States bordering the sea are integrated into the fields covered by cooperation.
One possible interpretation of article 123 is that it is based on the existence of areas under national jurisdiction such as EEZs. It refers to "States bordering the sea"; their rights in the fields of living resources, scientific research, the protection and preservation of the marine environment correspond to rights which arise from the creation of an EEZ or assimilated marine areas.