The British Indian Ocean Territory (BIOT) showing the extent of the 200 nautical mile Exclusive Fisheries Zone.
The Exclusive Fisheries Zone (EFZ)
Environment (Protection and Preservation) Zone
The outer limits of the Exclusive Fisheries Zone (EFZ), which is identical to the Environment (Preservation and Protection) Zone (EPPZ) (declared in 2003 to the United Nations) is the 200 nautical mile Exclusive Economic Zone permitted under UNCLOS (United Nations Convention on the Law of the Sea).
In the north, the UK claims a median line between the Chagos and the Maldives. This is disputed by the Republic of the Maldives whose own EEZ overlaps the BIOT EEZ. This dispute remains unresolved.
Marine Protected Area
A Chagos Islands Marine Protected Area (MPA) was proclaimed by the BIOT Commissioner on 1 April 2010 (Proclamation No 1 of 2010 - see file below for full text). This lies within the EPPZ.
To date there is no legislation for the MPA and no formal declaration that it is not to include the island of Diego Garcia and its 3nm territorial sea, although this appears to be the intention of the United Kingdom.
On 20 December 2010, the Mauritian Government initiated proceedings against the UK Government under UNCLOS to challenge the legality of the MPA. This matter is currently before an Arbitral Tribunal constituted under Annex VII. The case is expected to run until 2014 before any final decision is reached.
At a meeting on 23 March 2012 of the Marine Science Co-ordination Committee Meeting at DEFRA (Department for the Environment and Rural Affairs) the Head of the BIOT Section at the FCO, John McManus, informed attendees that the "sensitive political background, with the ongoing legal cases, has meant that the development of the MPA has been held back to a certain extent."