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Indian Ocean

Positioned around Madagascar, the four European overseas entities of the Indian Ocean region have specific characteristics and form a very mixed area. Réunion island and Mayotte are among the most densely populated areas in Europe, while the Scattered islands and Chagos archipelago are uninhabited.

Because of its very steep volcanic terrain, altitudinal biodiversity in Reunion is relatively well preserved. The issue of the BEST strategy will be related to the preservation of the coastal ecosystems. In Mayotte, if the EEZ is covered by a marine protected area, terrestrial ecosystems have no regulatory protection. The challenge will be to put in place tools to protect these ecosystems while allowing a sustainable development. The Scattered islands and Chagos archipelago are to face the issue of illegal fishing.

Main characteristics of the Region

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  • Two ORs : Reunion and Mayotte and 2 OCTs : Scattered islands (Tromelin, Glorioso, Juan de Nova, Bassas da India, Europa) and British Indian Ocean Territory (BIOT) also called Chagos archipelago formed by 5 atolls and 55 islands.
  • 7 ACP (African, Caribbean and Pacific Group of States) countries : Kenya, Tanzania, Mozambique, Madagascar, Mauritius, Seychelles, Comoros.
  • Location between Equator and Tropic of Capricorn. Tropical climate frequently hit by tropical cyclones. Annual rainfall typically ranges between 1,000 and 3,000 mm (and up to 10,000 mm by location in Reunion)
  • Total land area : Mayotte : 377 km², Reunion : 2,512 km², Tromelin : 1 km², Gloriosos : 7 km², Juan de Nova : 5 km², Bassas da india : 0 km² i.e. this is a high tide covered atoll, Europa: 30 km², BIOT : 60 km².
  • Total marine area : Mayotte : 68,381 km², Reunion : 315,058 km², Tromelin : 280,000 km², Glorioso : 43,614 km², Juan de Nova : 61,050 km², Bassas da India : 123,700 km², Europa : 127,300 km², BIOT : 640,000 km².

Socioeconomic, Policy and Civil Society Context

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  • Mayotte total population : 212,645
  • Reunion total population : 794,107
  • Scattered islands never had indigenous population nor permanent population. Today, there is a continuous human presence in some of these territories (scientists and logistics).
  • Mayotte GDP = 17.65 € per capita/year
  • Reunion GDP = 56.24 € per capita/year
  • Scattered island GDP = n/a
  • BIOT GDP = n/a
  • Environmental regional instruments and organisations : Nairobi Convention (for the protection, management and development of the marine and coastal environmental protection of the region), Commission of the Indian ocean (it supports and encourages national strategies of its member states to promote socio-economic development respectful of the environment).

Facts and Figures

Total Threatened species



Scattered islands


Number of endemic species

42 plants, 63 insects, 54 mollusks, 2 amphibia, 6 reptiles, 2 birds

240 plants, 600 insects, 20 mollusks, 7 reptiles, 11 birds, 1 mammal

2 mollusks in Europa, 1 reptile in Glorioso probably extinct

1 Ctenella chagius, a variety of brain coral believed to be endemic to the atoll

Total protected areas (number and % of the Total land and Total marine area)

Terrestrial : 10,135 ha

Marine : 6,839,515 ha (100% EEZ)

Terrestrial : 210,790 ha

Marine : 3,515 ha

Glorioso MPA : 4,300,000 ha

Europa : terrestrial : 205,800 ha

Marine : 54,400,000 ha (100% EEZ – no take)

Number of transboundary Protected areas

1 (Mayotte and Glorioso MPAs)

Number of BEST projects

1 conducted by Reunion (ONF)




Number of GEF environmental projects and CEPF projects





Main challenges

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  • In Mayotte : soil erosion is one of the major factors of the marine ecosystem degradation
  • Mayotte : maintaining the momentum initiated with the biodiversity strategy
  • Mayotte, Reunion, Scattered islands, BIOT : strategy against Invasive Alien Species

Importance for the Region to be involved in the BEST initiative

New sources of funding are needed to properly protect and manage the environment of Mayotte and Reunion. There is also a benefit to be interconnected with the other Overeas Entities within the initiative, as well as with regional neighbours. That gives the opportunity to capitalize on experiences led by others, in particular in the same area.

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