Abstract

Several decades ago，human activities are limited in the areas within national jurisdiction.Recently，with the development of science and technology，the impacts of human activities within the areas beyond national jurisdictions（ABNJ）continue to deepen，and the ecological environment of high seas has begun and is continuing to decline.The status of the high seas is unique in international law，which leads to the fragmented regulations and inadequate governance，thereafter，traditional marine legal instruments are ineffective to prevent further decline.Under this circumstance，two types of international law practices of setting up High Seas Marine Protected Areas（HSMPAs）began to attract the attention of the international community.The first type is the HSMPAs established and managed by regional marine organizations，for instance，the Commission for the Conservation of Antarctic Marine Living Resources（CCAMLR）and the Commission for the Protection of the Marine Environment of the Northeast Atlantic（OSPAR），which have successively set up several HSMPAs.The other type is the Area-based Management Tools（ABMTs）by international organizations，according to some international conventions’ authorizations to carry out their functions of protecting the marine environment，for instance，the“Special Areas”and“Particularly Sensitive Seas”of the International Maritime Organization.These practices have proven that well-managed HSMPAs will have a positive effect.Although the international community has repeatedly called for the protection of the global oceans through the establishment of HSMPAs，at the legal level，in addition to the only definition proposed by the Ad Hoc Technical Expert Group on Biodiversity COP in 2004，there is no generally-accepted definition for the HSMPAs.

Taking into consideration the fragmentation of regulations and governance in the high seas，the UN General Assembly，in its resolution 59/24 of 2004，decided to establish an Ad HocOpen-ended Informal Working Group to study issues relating to the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction（BBNJ）.On the outcome of the Working Group，the UN General Assembly in its resolution 69/292 of 2015 decided to establish a Preparatory Committee for development of an International Legally Binding Instrument（ILBI）under the United Nations Convention on the Law of the Sea（UNCLOS）on BBNJ conservation and sustainable use.The resolution also indicated that negotiations will address topics as a whole in this process，namely：MGRs，including questions on benefit-sharing；measures such as EIAs and ABMTs，including MPAs；and capacity building and marine technology transfer.No matter during the Working Group or the Preparatory Committee series meetings，representatives fully discussed the legal definitions of ABMTs and HSMPAs，including the progressive approach，the management measures，the objective of protecting，the existing practices in international law，etc.However，so far no effective consensus has been reached.

In the framework of international law，there are no legal authorities on the definition of HSMPAs.The only legal source is the definition under the Convention on Biological Diversity（CBD）by incorporating the MPAs definition system from the International Union for Conservation of Nature（IUCN）.Considering that IUCN is the pioneer and adherent to promoting the practices of MPAs and has conducted a large number of professional researches，its MPAs definition system is influential to both international law and domestic law.Many legal documents and institutions have a direct reference to IUCN's concept，including the Arctic Council and the Convention of CCAMLR.By analyzing the elements of IUCN MPAs definition，like defined geographical space，management tools，protection objects and objectives，we can find that this definition is very rigorous and operational.With further amendments to the relevant expressions and conceptual elements，IUCN MPAs definition has the potential to be applied in the high seas.

The precondition for IUCN MPAs definition to be applied to the high seas is whether this concept could be used to describe the existing international practices of HSMPAs and ABMTs.HSMPAs by regional marine organizations basically meet the elements required by IUCN's concept.These practices have provided vivid case materials for enriching the legal implications of HSMPAs，and further confirm the feasibility and necessity of establishing MPAs within high seas.The controversies and doubts in the practices also have posed challenges to the IUCN MPAs definition and called for the needs to further improve the concept of HSMPAs.So far no conclusion for the question whether the ABMTs of international organization could be included in the IUCN MPAs definition system.Owing to the different characteristics and purposes of various ABMTs by several international organizations，the existing ABMTs practices deviate from certain conceptual dimensions of the IUCN's definition of MPAs.The uncertainty about the coordination and combination between the ABMTs and HSMPAs is obviously not conducive to the comprehensive protection of the marine ecological environment.

The uncertainties and unclear legal meanings of the HSMPAs' legal implications have aroused many concerns from the international community，for example，some countries may take the opportunity to assert national sovereignty or jurisdiction to high seas and the HSMPAs practices may undermine the freedom of the high seas.Associating with the principle of common heritage of mankind，the continuous decline of the marine environment（especially the high seas）is a common concern of humankind（CCH）.The establishment and management of ABMTs and HSMPAs are effective countermeasures to respond to the common concern.As a treaty-binding concept，CCH provides useful enlightenments to prevent the disputes and questions arising from the international practices of HSMPAs.Therefore，the legal implications of the HSMPAs shall reflect the legal concept of CCH and an underlain principle of common but differentiated responsibilities.The legal implications of CCH is of great significance for assigning the obligations of protecting the high seas marine ecological environment to members of the international community，and attentions should be paid to the differences of developing countries，especially，the land-locked states and geographically disadvantaged states.On the basis of common but differentiated responsibilities illustrated in the international law of the sea and environment law，the legal implications of HSMPAs shall emphasize the specific mechanisms of financial assistance，technology transfer and capacity-building.

In the process of the systematization of international practices on the HSMPAs，China has actively participated in and formulated many useful suggestions on how to define the HSMPAs.Based on China's participation in the establishment and legislation practices of the HSMPAs and ABMTs，some of basic demands and ideas of China could be seen.Taking into account China's identity of being developing country and geographically disadvantaged country，China should balance the differentiated obligation to protect the high seas ecological environment and national interests in ABNJ，like the demand for offshore fishing，the rights to international seabed mining and the rights of scientific research in the polar regions，etc.In the process of developing a new ILBI，China shall promote a broad conceptual proposal of ABMTs（including HSMPAs）on the basis of summarizing the legal elements of the existing international practices，and actively promote the legal elements that are beneficial to China's interests in ABNJ to be stated or reflected in the legal implications of ABMTs（including HSMPAs）.

Keywords：High Seas Marine Protected Areas，International Law Practices，Legal Definition，Areas Beyond National Jurisdiction，Area-based Management Tools