The Cross-Fertilization of UNCLOS, Custom and Principles Relating to Procedure in the Jurisprudence of UNCLOS Courts and Tribunals

Cross-fertilization of international law entails interaction of norms in international law and can occur in the context of interaction between different sources of law; different branches of international law or different subject-matter areas; and interaction between a treaty norm belonging to a one area of international law and a customary norm arising from another area of international law. There are different avenues for cross-fertilization of international law: it can result from the application of Art. 31 (3) (c) of the Vienna Convention on the Law of Treaties (VCLT)1 in the process of interpreting a particular treaty, from the application of other rules of international law together with a particular treaty or from reference to the jurisprudence of other international courts or tribunals by adhering to the approach adopted in this jurisprudence. This article examines the question of cross-fertilization of international law in the context of the jurisprudence of the courts and tribunals operating within the dispute settlement system established under the UN Convention on the Law of the Sea (hereinafter ‘UNCLOS’ or ‘Convention’).2 It will demonstrate how these adjudicatory bodies have employed Art. 31 (3) (c) VCLT, Art. 293 UNCLOS which explicitly enables them to apply other rules of international law not incompatible with the Convention, and the international jurisprudence in order to interpret and apply the UNCLOS while situating it the broader context of international law. Note will be taken of UNCLOS provisions incorporating or referring to other rules of international law which also contribute to the cross-fertilization of international law.