Competing Claims to the Sea around Chagos
Figure 1. Mauritian claim to 200 nautical mile Exclusive Economic Zone (EEZ) 1977
The disputes over sovereignty have resulted in competing claims by Mauritius and the UK to the seas around the Chagos. The UK claimed median line between the BIOT and Maldives is also disputed by the Republic of Maldives.
In 1977 Mauritius first claimed a 12nm Territorial Sea and 200nm Exclusive Economic Zone (EEZ) in its Maritime Zones Act 1977. The inclusion of the Chagos into these claims as shown in Figure 1 was first made by a Regulation (Government Notice No 199 of 1984) on 27 December 1984.
On 12 March 2004 the UK deposited a list of coordinates with the UN for a 200 nm Environment (Protection and Preservation) Zone (EPPZ) which it had claimed the previous year (Figure 2) and on 1 April 2010 the UK claimed this same area as a Marine Protected Area.
On 14 April 2004, Mauritius responded to the EPPZ claim with a statement “protesting strongly against this declaration” and reasserting “its complete and full sovereignty over the Chagos Archipelago, including its maritime zones”.
Figure 2. Mauritian 200 nautical mile Exclusive Economic Zone (EEZ) and BIOT Environment (Protection and Preservation) Zone (EPPZ).
In June 2008 following its Maritime Zones Act 2005 which also updated its EEZ claim, Mauritius deposited geographical coordinates of its territorial sea with the UN which included archipelagic baselines in the Chagos. The UK responded by a Note Verbale which “protest[ed] strongly” and stated that the BIOT “is an Overseas Territory of the United Kingdom” followed by a response from Mauritius reasserting its claim to the Chagos.
In May 2009, Mauritius submitted preliminary information to the UN on a claim to an extended Continental Shelf some 170 miles beyond the southern edge of the Chagos EEZ. Preliminary claims are not dealt with by the UN until the full claim is submitted and the last available information (24 December 2015) is that Mauritius is in consultation with the UK with a view to a co-ordinated submission.
Page last updated: 28 October 2023