How open source technologies could dramatically reduce the cost of tagging green sea turtles.

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ZSL's Conservation Technology Specialist, Al Davies, travels to the island of Príncipe, West Africa, to test a new, cost effective, open source, green sea turtle tag.

Turtle tagging, Principe

I often like to describe the experience of working with green sea turtles (Chelonia mydas) to that of working with modern day dinosaurs. A reptile – the green sea turtle’s ancestors evolved on land and returned to sea over 140 million year ago, having witnessed both the evolution and extinction of dinosaurs - yet today they are classified as Endangered by the IUCN Red List of Threatened Species.

Threats include habitat destruction and the loss of their nesting beaches, plastic pollution in the ocean (plastic bags can be mistaken for jelly fish by sea turtles and are responsible for a great number of deaths) and bycatch through commercial fishing practices.

As a Technical Specialist within the ZSL Conservation Technology Unit, it’s my job to research and understand how the latest technological advances can be utilised to better protect and conserve species and their habitats globally. I am a firm believer in the implementation of open source technologies and an advocate of knowledge sharing to drive forward open solutions to achieve this. 

In the case of the green sea turtle, we recently embarked on a unique project to dramatically reduce the cost of tagging green sea turtles and acquire spatial and behavioural data using open source principles and technologies for the Príncipe Trust. The Trust’s goal is to promote the sustainable development of Príncipe island through research into nature conservation, tropical agriculture and education. Príncipe is the smaller, northern major island of the country of São Tomé and Príncipe lying off the west coast of Africa.

Their turtle monitoring program actively patrols and protects the many beaches used by sea turtles across the island and they wanted to understand the movement of nesting turtles to better protect their important marine habitats.

It’s traditionally expensive to tag sea turtles and collect spatial data. You need a robust waterproof enclosure capable of protecting the electrical components inside at great depths, satellite connectivity and advances such as salt water switch triggers and fast GPS acquisitions to achieve a GPS lock within seconds when the sea turtles come up to the surface to take a breath.

Commercial tags cost in excess of $2,000, and although well suited for the job and used extensively, we wanted to explore how new advances in open source manufacturing and technologies could achieve the same results, but at a dramatically reduced cost.

Mataki tags with size comparisson next to coins
Mataki tags

To do this, we worked with Luka Mustafa, a Shuttleworth Foundation Fellow and the founder of Inštitut IRNAS Rače. Luka’s team is pushing forward the boundaries of open source hardware development and design and were tasked with the challenge of creating an enclosure to host a low cost Mataki tag and AX3 accelerometer. Mataki tags, developed by Dr Robin Freeman of the Institute of Zoology at ZSL, are capable of transmitting logged data wirelessly via radio to Mataki base stations.

We wanted to place base stations on the known nesting beaches, tag the turtles with the new low cost tag and automagically acquire the logged data recorded by the Mataki when they returned to their nesting beaches. We nicknamed the tag the “Pit stop tag” as we designed it to be removable via a base plate, enabling researchers and beach guards to “swap” a tag out and replace it with a freshly charged tag without needing to apply fresh epoxy to attach and fix the tag in position.

We trialled the tag in January (2016) together with researchers from the University of Exeter. Green sea turtles will lay clutches of eggs 4 – 5 times every 10 – 14 days, so we tagged a turtle on its third clutch (knowing that it was loyal to the beach) and waited patiently for it to return. When it did, we were delighted to successfully communicate with the tag and download its logged data.

The tag’s enclosure costs ~$50 and the internal electronics $200, which is a dramatic cost reduction. Our next challenge is to explore and include an open source approach to rapid GPS acquisition and include a salt water switch to acquire reliable GPS locks when the turtles surface at sea. 

I see a future where open source technologies and the sharing of knowledge revolutionize the monitoring of species. Through the introduction of affordable and effective open solutions that are accessible to all, we can better collect, understand and analyse data, and importantly, act upon the knowledge acquired to make informed conservation decisions and ultimately protect and conserve endangered species such as the remarkable green sea turtle.

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