Chagos Archipelago

Chagos coral reef

Located 500km south of the Maldives, Chagos – also known as the British Indian Ocean Territory (BIOT) - is an archipelago of 55 tiny islands in the central Indian Ocean which are surrounded by some of the most vibrant coral reefs, diverse marine life and cleanest sea water in the world. In response to the action of a number of NGOs, of which ZSL was one, the British Government designated Chagos a no-take marine reserve in 2010. It is now the world's no-take largest marine protected area (MPA) at 640,000 km2, a landmark contribution to marine conservation. ZSL scientists, in collaboration with other organisations and institutions around the world, continue to study the biodiversity of Chagos to ensure the conservation and management of the reserve is effective.

Why we are there

The tropical reefs and islands of the Chagos archipelago cover an area of approximately 19,000km2 in the BIOT. It has a huge diversity of marine and terrestrial species, with some of the most undisturbed coral reefs in the world and eight times more reef fish than anywhere else in the Indian Ocean. This incredible diversity, some of which is unique to Chagos, is still under pressure from threats such as climate change and illegal exploitation.

The world's largest no-take MPA

Over 275,000 people called on the UK government to establish the Chagos region as a protected area in 2010. This decision was one of the most significant ways the UK could contribute to global marine conservation. ZSL was amongst the organisations that contributed to the science case for the reserve and that helped ensure its establishment. This is now the largest no-take marine protected area in the world, totalling more than 640,000km2, an area over twice the size of the UK.

Scientific expeditions

As part of the ongoing work of marine science researchers, ZSL scientists and conservationists join expeditions to study the reefs, islands and, more recently, the open ocean surrounding the Chagos Archipelago. This vital work increases our understanding of this little-studied part of the marine environment and ensures that the associated coastal and open-ocean ecosystems are managed effectively and remain healthy. 

Open ocean monitoring

As part of the ongoing work of marine science researchers, ZSL scientists and conservationists join expeditions to study the reefs, islands and, more recently, the open ocean surrounding the Chagos Archipelago. This vital work increases our understanding of this little-studied part of the marine environment and ensures that the associated coastal and open-ocean ecosystems are managed effectively and remain healthy. 

Connect Chagos: People and wildlife

As part of ZSL’s commitment to global and local conservation capacity building, a multi-phase project to build environmental skills and awareness within the Chagossian community in the UK and overseas has begun. 

Project information

Key species

Coral 

There are at least 220 species of coral on the reefs of the Chagos, including the Chagos brain coral (Ctenella chagius), a species which is probably endemic to these waters. Corals not only created the tiny atoll islands of the archipelago but thick stands of branching species continue to protect them from waves and storm damage.

Sharks & Rays

The Chagos supports a diverse array of sharks and rays from the coastal reef sharks to pelagic species such as the Shortfin Mako, Blue and Oceanic Whitetip sharks which patrol the open-waters. The Chagos is also home to reef manta rays and Whale sharks. 

Tuna

Prior to the MPAs establishment, tuna were commercially fished in the area. The main species targeted were the yellowfin, bigeye and skipjack tunas but a number of other species are also known to inhabit the rich Chagos waters including albacore tuna, dogtooth tuna and various species of mackerel.

People involved

ZSL’s Heather Koldewey manages the Chagos project overall, with Matthew Gollock leading on the pelagic fish studies and co-ordination from Rebecca Short.

David Curnick is a PhD researcher at ZSL and University College London investigating the role of large marine protected areas as a conservation strategy for pelagic tunas and sharks.

Audrey Blancart, Rebecca Short and Rudy Pothin are co-ordinating the community outreach programme.

Partners and sponsors

Chagos Environment Network; Marine Resources Assessment Group; University of Bangor; Chagos Conservation Trust; University of Warwick; University of Western Australia, Bertarelli Foundation, University College London,

Kindly funded by: PEW Charitable Trusts; Darwin Initiative - Overseas Territories Challenge Fund; PEW Environment Group; Defra; FCO; Waterloo Foundation; Blue Marine Foundation; Bertarelli Foundation; University College London; Rufford Small Grants Foundation.

News and blog links

David Curnick’s blog

Chagos expedition blog