Chagos Archipelago

Chagos coral reef

Located 500km south of the Maldives, the Chagos Archipelago – 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 water in the world.

Why we are there

The tropical coral reefs and islands of the Chagos Archipelago cover an area of approximately 19,000km2. It has a huge diversity of marine and terrestrial species, with some of the most pristine 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 the archipelago, is still under pressure from threats such as climate change and illegal exploitation.

The world's largest no-take Marine Reserve

Over 275,000 people and a number of NGOs called on the UK Government to establish the territorial waters of the Chagos Archipelago as a Marine Reserve in 2010. ZSL was amongst the organisations that contributed to the science case for the creation of the reserve and that helped ensure its establishment. It is now the world's largest no-take Marine Reserve at 640,000 km2,an area twice the size of the UK. This decision was one of the most significant ways the UK could make a landmark contribution to global marine conservation. 

The Chagos Archipelago: six years on

It's six years since the waters of the Chagos Archipelago were designated the world's largest marine reserve. Since then, ZSL has been working with many other organisations to research the astounding array of wildlife that lives there, and making significant advances in marine science and conservation. Read more about our discoveries on  Heather Koldewey's blog, and check out our infographic of Chagos in numbers

Scientific expeditions

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

Open ocean monitoring

More recently ZSL has been involved with open-ocean and deep sea monitoring. Using state of the art underwater cameras and tagging technology, presence and movement of top ocean predators is being documented for the first time.

Connect Chagos: People and wildlife

As part of ZSL’s commitment to global and local conservation capacity building, Connect Chagos was created four years ago as a multi-phase project to build environmental skills and awareness within the Chagossian community in the UK and overseas.

Project information

Key species


There are at least 310 species of coral on the reefs of the Chagos Archipelago, including the Chagos brain coral (Ctenella chagius), a species endemic to these waters. Corals not only created the tiny atoll islands of the Archipelago but thick strands of branching species continue to protect them from waves and storm damage.

Sharks & Rays

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


Prior to the Marine Reserve's 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 waters including albacore tuna, dogtooth tuna and various species of mackerel.


People involved

ZSL’s Heather Koldewey manages ZSL's work in the Chagos Archipelago, with Matthew Gollock leading on the pelagic fish studies and co-ordination from Kirsty Richards.

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.


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


Connect Chagos 2015

The Project 

The Connect Chagos Project was created in 2012 to engage with Chagossian communities based in the UK in order to increase environmental awareness and to contribute to the conservation of the Chagos Archipelago.

Staff from the Connect Chagos Project worked in Crawley and Manchester, hosting events such as Environmental Open Days and Tailored Sessions to actively engage with the community and to increase awareness of the extraordinary environment of the Archipelago.

Each summer an Environmental Training Course was run, in partnership with many conservation organisations, which covered a variety of nature-related topics from bird monitoring, habitat management and marine conservation. Individuals who successfully completed the training course were then invited to apply for bursaries to fund advanced training and to join a scientific expedition to the Chagos Archipelago.

From 2012 – 2015 the project actively engaged with >700 community members from Crawley and Manchester. 42 ambassadors completed the environmental training course, 19 of which went on to carry out advanced training which included chainsaw training and gaining SCUBA diving qualifications. 7 ambassadors have joined scientific expeditions and one individual has recently represented the community at a “Big Oceans” meeting in Hawaii. 

Connect Chagos 2015

The Connect Chagos Book

The book was created as a lasting legacy of the project and as a resouce for the community. It's colourful pages contain information on each of the topics covered during the training course. Starting with an "Introduction to Conservation" it not only educates the reader on the wonderful environment of the Chagos Archipelago but provides useful hints and tips for learning about our wildlife here in the UK. A PDF version can be downloaded below, or contact Kirsty Richards to be sent a hard copy.

PDF icon The Connect Chagos Book (5.36 MB)



Connect Chagos Environmental Training Course Film 2014.


Contact Connect Chagos:

Kirsty Richards

Connect Chagos : People & Wildlife 2014 Booklet

PDF icon Connect Chagos 2014 Booklet (9.49 MB)


Foreign and Commonwealth Office

Chagos Conservation Trust

Darwin Initiative

Partners & Supporters

Bangor University



Manchester Museum

Blue Ventures

Yu Diving

London School of Diving

The Deep Aquarium

The Horniman Museum

City of London

The Ness Botanical Gardens

Natural England

Sayers Croft