The UN member states have been consulting on the establishment of high seas MPAs under the BBNJ Agreement since December 2017.This issue brings about the potential conflicts between the jurisdiction of the high seas MPAs and the traditional freedom of the high seas. Although it is generally accepted that the freedom of the high seas can be reasonably restricted, it is acknowledged that there are great controversies among States on the specific forms, approaches and applicable scopes of the restrictions of the high seas freedoms by the high seas MPAs. At present, there are four recognized high seas MPAs in the world. The practice of these four MPAs contributes positively to the interpretation of the reasonable restrictions on the freedom of the high seas. Accordingly, this paper concludes that the international community should gradually carry forward future restrictions on the freedom of the high seas with some suggestions.

I. Introduction
II. An Overview of the Principle of the High SeasFreedom and Its Reasonable Restrictions
III. Major Controversies Arising from ReasonableRestrictions on the Principle of the High SeasFreedoms during BBNJ Negotiations
IV. A Positivist Analysis on Reasonable Restriction tothe High Seas Freedoms under the High Seas MPAs
    A. Main Management Measures of the Four High Seas MPAs forthe Contracting Parties
    B. Management Measures of the Four High Seas MPAs for NoncontractingParties
    C. The Jurisdiction Regime of the Four High Seas MPAs over IllegalShips
V. General Ideas Restricting the High SeasFreedoms by the MPAs
    A. Reality and Graduality
    B. Positive Law
    C. Legal Objectivity
VI. Details for the Reasonable Restrictionson the High Seas Freedoms
    A. The Management Measures of the High Seas MPAs without theObligations on Non-Contracting Parties
    B. The Management Measures of High Seas MPAs under the Rightto Visit and the Long-arm Jurisdiction
    C. Soft Law and Exception Rules
VII. Conclusion

• Yong Wang(International Law at East China University of Political Science and Law (“ECUPL”))