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 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 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 and a number of NGO's called on the UK Government to establish the territorial waters of the Chagos Archipelago as a Marine Protected Area (MPA) 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. 

Chagos: five years on

It's five years since the waters around Chagos 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 is now in its third year.

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. Chagos is also home to majestic animals such as reef manta rays and whale sharks. 


Prior to the MPA'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 Chagossian 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 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.

Rudy Pothin, Kirsty Richards and Amdeep Sanghera are co-ordinating the Connect Chagos 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


Connect Chagos Reunion Weekend, October 2014
Connect Chagos Reunion Weekend, October 2014
As part of ZSL’s ongoing work focused on the Chagos marine reserve we are delivering an outreach and environmental education project. Through a suite of community days, nature taster sessions and the Connect Chagos Environmental Training Course we aim to connect Chagossian people in the UK and overseas with their natural heritage as well as building employable skills.


Connect Chagos Environmental Training Course Film 2014.


Connect Chagos Environmental Training Course 2015

Connect Chagos Training Course 2015The 2015 Chagos Environmental Training Course is now well underway with 12 new trainees from Manchester and Crawley. We have already completed our introductory session here as ZSL in London where the trainees learnt all about the Connect Chagos project, ZSL and even had a chance to meet some of the zoo's keepers along with Priscilla one of our Galapagos Tortoises and Forest our elusive Kinkajou.

Coming up next is a trip to KEW, Wakehurst followed by our marine sessions learning all about corals and the incredible marine environment of the Chagos Archipelago.




Contact the Connect Chagos team

Connect Chagos Project Support Officer: Amdeep Sanghera

Connect Chagos Outreach Assistant: Rudy Pothin

Connect Chagos Project Co-ordinator: Kirsty Richards

Connect Chagos : People & Wildlife 2014 Booklet

Connect Chagos 2014 Booklet cover

PDF icon Connect Chagos 2014 Booklet (9.49 MB)


Partners, Supporters and Sponsors

Chagos Conservation Trust

Darwin initiative

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