The term " jurisdictionalisation" is ambivalent, particularly when applied to marine areas.
It may mean the appearance of jurisdiction exercised by a coastal State without any legal foundation, which leads to the deplorable phenomenon in the law of the sea commonly known as "creeping jurisdiction". A State attempts to exercise rights which are not among those to which it is entitled: for example, by attempting to subject the laying of underwater cables to its authority, whereas the law of the sea lays down the principle of freedom to lay cables in an area under its jurisdiction. Any attempt made by a coastal State to extend its rights without any legal basis to that effect can be described as creeping jurisdictionalisation.
It may also mean a coastal State's decision to take advantage of rights which are authorized by the law of the sea, but which may only be exercised through the creation, under the State's national law, of a marine area under its authority. One virtually unique example is that of the Exclusive Economic Zone (EEZ): sovereign rights and jurisdiction as defined by the UNCLOS may only be claimed by the coastal State, and imposed upon Other States, following the creation of the EEZ by its national legal system. When it is a matter of an option (there is no obligation to create such a zone), any move towards the creation of an EEZ enters the jurisdictionalisation category.
While the first kind of jurisdictionalisation can be contested, the second is, from a legal point of view, perfectly well-founded and legitimate.
The confusion felt by a number of players in the field of maritime governance of the Mediterranean arises from the fact that the non-creation of zones under national jurisdiction had become customary and their increasing number over the past few years, under various designations, has resulted in blockage-related hypotheses due to the numerous delimitations to be undertaken, because of overlapping national jurisdictions. This feeling so specific to the Mediterranean region has arisen because it is a semi-enclosed sea in which ecologicial interdependence is even stronger than elsewhere in the open ocean. States must work in solidarity to confront the challenges raised by the fragility of the environment, and jurisdictionalisation, even in its legitimate form, is seen as an additional hurdle in the quest for effective protection.
The effects of jurisdictionalisation and its long series of negotiations for the delimitation of marine areas should not be exaggerated. Creating an area under national jurisdiction in order to exercise recognized rights is a procedure bringing legal clarity; without it being done, the area remains under the regime of the high sea, with all the uncertainties that this can cause: what can be done on the high sea to protect the marine environment? How can protected marine areas be created there?
Jurisdictionalisation via the creation of zones conforming to the UNCLOS provides a possible framework for regional or sub-regional cooperation between States whose boundaries touch each other in the sea; they can jointly address shared problems over and beyond their maritime delimitations, whether they exist already or are to be established. The philosophy behind article 123 of the UNCLOS  is wholly in favour of this interface between cooperation and national jurisdiction.
Jurisdictionalisation of the Mediterranean is a recurrent theme in workshops organized by the IUCN. Sometimes, delimitation issues indeed seem to be inextricable, even impossible, due to the region's history, geography and current geopolitical importance. The heterogeneous arrangements, their uncertainties and contradictions, the wealth of jurisdictions, cloud any prospect of integrated management that would be really effective. Furthermore, the marking of limits or boundaries seems radically incompatible with the ecosystems' dynamics. Also, in many cases, the modus operandi of coastal States contradicts their regulatory duties in the field of cooperation. Finally, the effectiveness of their powers, either recognized or claimed, is sometimes extremely relative.