Between Consent and Effectiveness: Incidental Determinations and the Expansion of the Jurisdiction of UNCLOS Tribunals

This paper discusses the legal framework within which the jurisdiction ratione materiae of tribunals established under UNCLOS Part XV can be extended, at least incidentally, over non-UNCLOS issues. The analysis illustrates that, whilst UNCLOS Tribunals—like other international tribunals—have an incidental jurisdiction to determine incidental issues beyond the scope of their principal jurisdiction, a consistent and well-developed doctrine relating to such incidental jurisdiction is still lacking. The Chagos award provides some hints about the features of this jurisdiction, but essentially refers to judicial assessments which remain to a large extent discretionary. The same holds true when it comes to the determination of the legal effects of incidental determinations over external issues. In this paper it is argued that further clarification about such prominent aspects of the adjudication of law of sea disputes is needed. This would help achieving a better balance between the principle of consent and the principle of effectiveness in the exercise of Part XV jurisdiction.