Delimitation of maritime boundaries and the primacy of geography: reflections on the delineation of Turkish maritime jurisdiction

The International Law of the Sea remains largely customary, although it has been the focus of codification efforts at United Nations (UN) conferences in which Türkiye has actively participated. Maritime Boundary Delimitation Law, a sub-branch of the International Law of the Sea, has no clear written rules and instead has been shaped by judicial decisions. This study has examined the stages of an equitable delimitation of maritime jurisdiction as decided by international judicial decisions, including the consideration of "relevant/special circumstances" in delimitation. Among these circumstances, "geography" as a relevant circumstance, outweighs other relevant/special circumstances in the balancing up of equities. It has been consistently demonstrated through judicial practice that for a state to possess sovereignty over maritime jurisdiction, it must have a "coastline"; sovereignty over land can only extend to the seas through the coast, and coastal geography is given primacy. An equitable delimitation aligns with the most appropriate delimitation for the coastal geography. In this context, coastal geography plays a vital role as a dynamic factor in adapting the provisional line, drawn purely by geometry, to equity; and in testing the proportionality of the equitably adjusted area. Thus, this study discusses the primacy of geography in the delimitation of maritime jurisdictions based on judicial practice. This study evaluates both the theoretical aspects of the delimitation of maritime jurisdiction and the primacy of geography, as well as their practical implications on the delineation of Turkish maritime areas, identifying current practices and disputes among the parties concerned. In conclusion, this thesis has demonstrated that the primacy of geography aligns with equity to a proportional extent in the delimitation of Turkish maritime jurisdiction.