Mauritius v. United Kingdom: Submission of the dispute on the Marine Protected Area around the Chagos Archipelago to arbitration

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Irini Papanicolopulu is Marie Curie Fellow, Faculty of Law, University of Oxford and a Senior Researcher in international law at the University of Milano-Bicocca (on leave).

On 20 December 2010, Mauritius initiated proceedings against the United Kingdom under the dispute settlement provisions of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) (see report here). The dispute, to be submitted to an arbitral tribunal (since both States have opted for different dispute settlement methods under UNCLOS), concerns the creation by the United Kingdom of a marine protected area (MPA) up to the outer limit of the exclusive economic zone of the Chagos Archipelago. According to the notification and statement of claim,

Mauritius requests the Annex VII arbitral tribunal to declare, in accordance with the provisions of UNCLOS and the applicable rules of international law not incompatible with the Convention that, in respect of the Chagos Archipelago:

  • The ‘MPA’ is not compatible with the 1982 Convention, and is without legal effect; and/or
  • The United Kingdom is not a ‘coastal state’ within the meaning of the 1982 Convention and is not competent to establish the ‘MPA’; and/or
  • Only Mauritius is entitled to declare an exclusive economic zone under Part V of the 1982 Convention within which a marine protected area might be declared.

Background to the dispute

The Chagos Archipelago, situated in the Indian Ocean, consists of some 65 islands for a total of approximately 60 sq km, generating marine areas that cover 54,400 sq km of ocean; the biggest island, Diego Garcia, has a surface of 44 sq km (see here and here). Formerly under UK colonial rule, since 1965 the Chagos Archipelago forms the British Indian Ocean Territory (BIOT). In the period 1967-1973 the inhabitants of the islands were forcibly displaced to Mauritius, Seychelles and the United Kingdom and were prevented from returning to the archipelago. This forced removal has been challenged before the courts of the United Kingdom and the United States and a case is now pending before the European Court of Human Rights. From the late 60s, the island of Diego Garcia has been leased to the United States of America, which has constructed and operates a military base. Since its independence in 1968, Mauritius has claimed sovereignty over the Chagos Archipelago including Diego Garcia, while the United Kingdom has repeatedly declared that it will cede the islands to Mauritius when they are no longer needed for defence purposes.

The creation of the MPA

The application of Mauritius was triggered by the creation, in April 2010, by the United Kingdom of a marine protected area (MPA) including the territory, territorial waters and exclusive economic zone of the BIOT, with the exclusion of the military base on Diego Garcia. The MPA is a no-take area, where fishing is completely banned. The reasons given by the British Government for the creation of this MPA were the need to preserve the marine environment and augment the coverage of protected areas globally. As has been affirmed by environmental organisations which have supported the creation of the MPA (including IUCN and Greenpeace)the marine ecosystems of Chagos, including coral reefs, are particularly healthy and pollution in the area is low. The British Government has affirmed that the creation of the MPA is without prejudice to the cession of the Chagos to Mauritius when no longer needed and to the outcome of the case pending before the European Court of Human Rights. The recent publication of some Wikileaks documents, however, shows British officials stating that the creation of the MPA will be the best way to avoid any claim for resettlement of the evicted population (see here).

Claims by Mauritius

In its application, Mauritius contests the legality of the MPA on the basis of different grounds. In the first place, Mauritius contends that the United Kingdom is not the coastal State in this case. Secondly, according to Mauritius, the United Kingdom has failed “to have due regard to the right of Mauritius and those persons forcibly removed from the Chagos Archipelago”, to comply with the UNCLOS and “to seek to reach agreement with Mauritius or appropriate subregional or regional organisations … on measures necessary to ensure conservation”. Finally, referring to the Wikileaks materials, Mauritius considers that “the true purpose of the MPA is not conservation but to prevent the right of return”.

The core issue at dispute is therefore the legality of the MPA, as created by the United Kingdom. While the application just sketches the arguments, there are apparently different grounds on which Mauritius bases its claims, some spelled out clearly, others which may be inferred by the language used in the application. A first argument challenges the right itself of the United Kingdom to act as the coastal State and create a MPA in any zone of the BIOT, and its solution depends on the weight given to the territorial claims of Mauritius and on whether the UK is to be considered, at least for the time being, as the coastal State. Secondly, there is the issue of the compatibility of unilateral action with the requirements set by international law, a line of argument intermingled with the question of the width of the MPA. The unilateral creation of marine protected areas by a State is indeed not prohibited by the UNCLOS, Art. 194(5) rather providing for it, and is expressly provided for in other treaties (e.g. Art. 11 of the 2010 Amended Nairobi Convention for the Protection, Management and Development of the Marine and Coastal Environment of the Eastern African Region). State practice, however, usually consists in the creation of marine protected areas of limited extension and with a, often complex, zoning scheme permitting for both protection and the conduct of other activities not incompatible with environmental conservation. Marine protected areas encompassing tens of thousands of sq km are the exception and measures applicable therein are usually the object of agreement between interested States or within international organisations. While scientists and environmental organizations are requesting bigger and more numerous marine protected areas, the difficulties encountered in ensuring the application of environmental legislation and the possible impact that wide no-take zones may have on nearby waters, which conversely risk over-exploitation, but also, and primarily, the need to adopt a more holistic approach that takes into account the needs and concerns of local populations are also acknowledged (see Thomas Greiber, Melinda Janki, Marcos Orellana, Annalisa Savaresi, Dinah Shelton, Conservation with Justice A Rights-based Approach). In the third place, Mauritius seems to contest the procedure chosen by the United Kingdom for creating the MPA. While the United Kingdom conducted a public consultation before instituting the MPA (the report of the consultation is available here), it is claimed by Mauritius that the final unilateral decision by the British Government also violated the rights of those – States, groups and individuals – more closely concerned with the Chagos Archipelago, by not sufficiently involving them in the decision-making process. In this respect, Mauritius refers to Chapter XI of the United Nations Charter and the principle of permanent sovereignty over natural resources, but also to the fact that the creation of the MPA de facto cancels the fishing rights enjoyed by Mauritius up to 2010. Finally, there is the claim that the British acts do not comply with Art. 300 UNCLOS (Good faith and abuse of rights), motivated by the Wikileaks documents as published by newspapers. Similar claims have failed being accepted by international judges in the past, especially because of the difficulties in proving the subjective element required by such rules. If however they were to be considered in the merits of the present case, then interesting questions as to the admissibility of the Wikileaks material could be raised, that might constitute guidance on the use of similar material in other instances.


All claims outlined above could however never reach the adjudicatory stage, since there might be an issue about the jurisdiction of the arbitral tribunal to decide the case. According to the disputes settlement mechanism of UNCLOS, parties to the Convention must submit their disputes to binding settlement (Art. 286), subject to a previous exchange of views (Art. 283), with the exception of disputes excluded by virtue of Arts. 297 and 298. Art. 297(1) provides that the exercise by a coastal State of its rights and jurisdiction can be submitted to judicial settlement only in specific cases, which include however

 (b) when it is alleged that a State in exercising the aforementioned freedoms, rights or uses has acted in contravention of this Convention or of laws or regulations adopted by the coastal State in conformity with this Convention and other rules of international law not incompatible with this Convention; or

(c) when it is alleged that a coastal State has acted in contravention of specified international rules and standards for the protection and preservation of the marine environment which are applicable to the coastal State and which have been established by this Convention or through a competent international organization or diplomatic conference in accordance with this Convention.

 On the other hand, para. 3 of the same article excludes from binding settlement any dispute “relating to [a coastal State’s] sovereign rights with respect to the living resources in the exclusive economic zone or their exercise”. If its jurisdiction is challenged, as indeed seems probable, the arbitral tribunal will have to address at least two issues: whether the entitlement of a State to be considered the coastal State and therefore to proclaim marine zones, such as the exclusive economic zone, is a matter relating to law or the sea or to law on title to territory, and whether the creation of a no-take protected area encompassing all of the exclusive economic zone of a territory pertains to the exercise of the sovereign rights over resources (under Art. 56(1)(a) UNCLOS) or rather to the exercise of jurisdiction to protect the marine environment (under Art. 56(1)(b)(iii) UNCLOS). These two issues are not necessarily interdependent: the arbitral tribunal could deal with the merits of the second even if it were to decide that it does not have jurisdiction with respect to the first. In any event, the tribunal will be prevented from directly considering aspects of the dispute concerning military activities and law enforcement activities in respect of scientific research and living resources, since the United Kingdom has made a declaration under Art. 298(1)(b).

 The case presents undoubtedly interesting aspects. Even without entering into the merits of the real motivations behind the declaration of the BIOT as a marine protected area and by accepting that environmental concerns where indeed the driving force, this case raises topical questions. In addition to the more detailed ones presented above, the judge might be called to address the interaction and potential conflict – not so much between the protection of the environment and human rights including economic rights – but rather between unilateral and authoritarian ways of furthering strictly environmental agendas, on one hand, and action through multilateral cooperative frameworks that work towards shared decisions and tend to accommodate not only environmental, but also social and economic concerns, on the other.

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