[Coral-List] Chagos Islands - Law of the Sea – Determination that Mauritius is now the ‘coastal State’

[Richard Dunne]

On Jan 28, 2021 the International Tribunal for the Law of the Sea 
(ITLOS) published a judgment in a case concerning the maritime boundary 
between the Maldives and Mauritius (Chagos) 
(https://www.itlos.org/fileadmin/itlos/documents/cases/case_no_28/C28_Judgment_prelimobj_28.01.2021_orig.pdf).

The judgment took account of an earlier decision in 2015 by an Arbitral 
Tribunal concerning the Chagos Marine Protected Area (MPA), an Advisory 
Opinion in 2019 of the International Court of Justice (ICJ), and a UN 
General Assembly Resolution 73/295 of May 22, 2019.

The ITLOS Tribunal held that the ICJ’s Advisory Opinion had been 
determinative of the question of the sovereignty of the Chagos, and 
notwithstanding the fact that the UK currently refuses to end its 
administration, Mauritius is to be regarded as the ‘coastal State’ for 
the purposes of the UN Convention on the Law of the Sea (UNCLOS).

This ruling thus establishes conclusively that under UNCLOS, Mauritius 
now has sovereignty over the territorial sea of the Chagos (claimed by 
Mauritius out to 12nm) and rights and jurisdiction over the EEZ (which 
has also been claimed by Mauritius out to 200nm) and the continental shelf.

The consequences of the ITLOS ruling for the UK’s continued 
administration of the Chagos are serious. For example, the patrolling 
and arrest of fishing vessels by the UK anywhere in the Chagos would now 
be unlawful, and it no longer has the right to grant permissions for 
scientific research. Its claim to an MPA no longer has legal effect. The 
UK will undoubtedly lose its membership of the Indian Ocean Tuna 
Commission later this year. Its fisheries management policies for the 
Chagos are unworkable, with potentially dire consequences for marine 
conservation in the area.

As scientists and other concerned individuals what should we do? 
Firstly, we should now encourage Mauritius to declare a new MPA in the 
Chagos to protect the area and its resources. We should lobby the UK to 
recognise the reality of the situation and to acknowledge that it will 
return the islands to Mauritius promptly and without further delay. 
Finally, we should desist from referring to the Chagos Islands as the 
‘British Indian Ocean Territory’ in our papers and research, in this 
context the recent use of “Mauritius (Chagos)” by UNEP has met with 
approval by Mauritius.

Richard P Dunne

Barnard Castle, Co Durham, UK