Sea Turtle Expedition to Diego Garcia

by Emma Levy on

After a hugely successful sea turtle expedition to Diego Garcia, British Indian Ocean Territory (BIOT), Nicole Esteban from Swansea University writes an update on the work achieved.

Our recent sea turtle expedition to Diego Garcia ran from 25 June to 18 July 2018. The primary conservation research objective was to increase our understanding of sea turtle movements within and outside of the British Indian Ocean Territory (BIOT). Satellite tags were attached to 12 nesting green turtles, bringing our total number of equipped nesters to 35 since we commenced this work in 2012. Additionally we equipped the first immature turtles, with eight hawksbill and two green turtles being satellite tagged in the Diego Garcia lagoon. Our long-term mark-recapture monitoring programme at Turtle Cove in the south of Diego Garcia lagoon was continued, with some immature turtles first flipper tagged in 1996. Additional objectives were to conduct an island-wide survey of turtle nesting activities and to deploy temperature loggers recording sand temperature to monitor turtle nesting incubation conditions in different beach zones.


Turtle team. DG, BIOT. Nicole Esteban
Members of the expedition team from left: Nicole Esteban, Jeanne Mortimer, Graeme Hays, Antenor Guzman, on the first day of immature turtle surveys at Turtle Cove

We commenced the expedition with a presentation about sea turtle conservation research in BIOT to a packed audience of around 100 military and civilian residents of Diego Garcia. Throughout our work we received tremendous support from personnel on Diego Garcia with 122 volunteers helping with our fieldwork.

Graeme Hays presenting on turtle research and volunteer opportunities. DG, BIOT. Nicole Esteban
Packed audience attend the sea turtle conservation research talk and volunteer sign-up at the start of the expedition.

We wait with baited breath to see the migration destinations of these turtles we equipped this year. In previous years, nesting turtles from Diego Garcia have broken the records for long distance migration with some individuals travelling to the African coast >4,000 km distant.  But not all of the turtles travel so far, with some travelling only 80 km to the Great Chagos Bank. We hope to uncover the reasons for this huge variation in migration distances.

Volunteers assisting with tagging green turtle. DG, BIOT. Nicole Esteban
Volunteers assisting with a satellite tag attachment at night to a green turtle that had completed nesting

This research was kindly funded by the Bertarelli Foundation as part of the Bertarelli Programme in Marine Science.

Select a blog

Careers at ZSL

Our people are our greatest asset and we realise our vision for a world where wildlife thrives through their ideas, skills and passion. An inspired, informed and empowered community of people work, study and volunteer together at ZSL.

Nature at the heart of global decision making

At ZSL, a key area of our work is the employment of Nature-based Solutions – an approach which both adapt to and mitigates the impacts of climate change. These Solutions, which include habitat protection and restoration, are low-cost yet high-impact, and provide multiple benefits to people and wildlife. We ensure that biodiversity recovery is at the heart of nature-based solutions. 

ZSL London Zoo

A blog for lovers of ZSL London Zoo, bringing you extraordinary animal facts and exclusive access to the world's oldest scientific zoo.

ZSL Whipsnade Zoo

Do you love wildlife? Discover more about our amazing animals at the UK's biggest zoo!


We're working around the world to conserve animals and their habitats, find out more about our latest achievements.


From the field to the lab, catch up with the scientists on the cutting edge of conservation biology at ZSL’s Institute of Zoology.


A day in Discovery and Learning at ZSL is never dull! The team tell us all about the exciting sessions for school children, as well as work further afield.

Artefact of the month

Every month, one of the pieces held in ZSL’s Library and at ZSL Whipsnade Zoo will feature here as Artefact of the Month.

Wild About

Read testimonials from our Members and extracts from ZSL's award winning members' magazine, Wild About.

Chagos Expedition

The Chagos archipelago is a rare haven for marine biodiversity. Hear from the team about our projects to protect the environments in the British Indian Ocean Territory (BIOT).

Asia Conservation Programme

ZSL works across Asia, from the famous national parks of Nepal to marine protected areas in the Philippines. Read the latest updates on our conservation.

Remote Sensing in Ecology and Conservation

An Open Access journal for research at the interface of remote sensing, ecology and conservation.