article / 12 March 2019

Update on Arribada's Low Cost Open Source Sea Turtle Tag

Current efforts to track endangered Green Sea Turtles rely on tags that cost upward of $2000 per unit. The Arribada Initiative and the Zoological Society of London have been developing a new open source solution for tracking marine species. Here Rachael Kemp, who has been leading the project since December 2017, provides updates on progress so far and plans for the future.

In Alasdair Davies’ update from May 2016, he discussed work to deploy Mataki tags inside new custom made enclosures in order to explore how nesting green sea turtles use their environment during their time at sea between nests. The target from this early stage was to reduce the cost of tracking sea turtles by 90%, giving the potential to expand sample sizes ten-fold. This not only helps scientists make more accurate conclusions, but it can help conservationists put pressure on governments to implement marine protection measures.

Where we are now

Since then we’ve come a long way. Mataki tags did obtain some data during these tests but they were not tuned for the marine environment, so we knew that better data would be in reach if we refined this technology. We wanted to create a low cost, open source version of a commercially available sea turtle tag fully optimised to gather data in the marine environment.

Marine animals (inconveniently) are highly specialised for long periods underwater, only surfacing occasionally to take a breath. This means that trackers deployed on such species have only the briefest window of time to wake up and take a ‘fix’ before the animal dives again. Trademarked software (e.g. Fastloc ™) exists to help get an accurate position quickly but this can add further expense. Our mission was to design a tag using off-the-shelf components and open designs to create a flexible, low-cost solution that could still acquire quality data.

tagged turtle

Together with our technical partner, Icoteq Ltd., we have integrated a uBlox GPS module enhanced with pre-loaded almanac tables and paired this with pressure sensors and a saltwater switch to wake our tag and ready the GPS to obtain quicker locks when the animal approaches the surface. The board incorporates a gyrometer, accelerometer, temperature and pressure sensor. Due to its open design, the reference design can be rapidly re-spun with different sensors and capabilities. Bluetooth 5.0 is enabled for high-throughput communications over distances of up to 100m, suitable for downloading data from a female when she returns to the beach to nest.

A small, cost-effective enclosure has been designed and trialed with our partner Institute Irnas, which allows a researcher to use traditional fiberglass/epoxy resin methods to apply the tag to the shell of the green sea turtle. We have a reusable base plate that allows tags to be easily switched with freshly charged ones when a female returns to the beach. The casing has been tested to pressures of 300m and has shown no water ingress during field deployments.


Testing, testing...

The above iteration of the tag was deployed on turtles with the University of Exeter in Cyprus, where all ten tags returned with GPS data. Our tags achieved over four times the total number of fixes at sea compared to an off-the-shelf tag of a similar price point (the i-gotU tag) that had been deployed in Cyprus during the 2013 and 2014 nesting seasons under very similar circumstances. i-gotU tags are simple and affordable GPS devices used for sports tracking, often repurposed for wildlife monitoring, but we believe an open solution would offer a cost reduction and enhanced functionality. This great result highlighted that open source can deliver improved performance without increasing the cost.

As a quick reminder, we have also developed open source optical tags for marine turtles and achieved some great results during deployments on Principe island. This allows researchers to track turtles’ behaviour and interactions with threats beyond what they would usually see, and preliminary results from our deployments so far have shown interactions with plastic in almost a third of the footage. We have been working with WWF Kenya to train their team in the use and application of these tags and they hope that these will be of similar help in tracking the impact of the plastic problem off their shores. In the future, it would be great to combine both the GPS and camera elements so that we can more accurately identify where plastic is found and possible sources.

We have been experimenting with different models for manufacturing and distributing technology to keep costs low to conservationists. By using group purchasing initiatives (e.g. GroupGets) to bulk up orders and reduce the per-unit cost to the user; along with on-demand manufacture initiatives (e.g. CircuitHub), to keep manufacture costs at a minimum; and fulfillment houses to take care of delivery (e.g. Weengs); we have shown that it is possible to produce quality technologies at low cost. This model works particularly well for relatively low-cost, high unit volume technologies such as GPS tags and the Audiomoth. This approach also allows profits to be reinvested to support the technology developers themselves.

This helps avoid a common pitfall with many open source initiatives where technologies can be tied to specific project cycles and funding, with sustainability to maintain and further develop the technology being difficult to achieve.

open source graphic

Looking ahead

We continue to work on software iterations and bug fixes, as well as further deployments to test and harden the product. We are working to optimise battery life and enclosures, ensure tags operate consistently as we expect, and create a user-friendly experience with some simple software, ahead of releasing the designs. We hope that our platform will inspire the open-source conservation community to build on our work, using our designs to create the custom solutions they need. We are really excited about new initiatives such as Open Collar that are already using the Arribada tag as a base to create the first Open Collar tag.

We also have plans to incorporate long-range radio and satellite communications so that migratory species can be tagged, and we hope to decrease the footprint of our tag so that it can be used on a variety of other species.

Over the coming months, I will endeavour to keep you up to date here and in the WILDLABS Wildlife Tracking group. If you want to get in touch or have any questions, please feel free to reach out to me at this address.

About the author

Rachael Kemp is Project Manager for the Zoological Society of London and Arribada Initiative’s collaborative project to develop open source tagging technologies for wildlife. She manages the development of GPS and optical tags for use on turtles, including field testing on Principe in the Gulf of Guinea, Cyprus, Kenya, and Guinea Bissau, and associated community outreach and capacity building work. Rachael has a BSc in Natural Sciences from the University of Bristol and an MRes in Biosystematics from Imperial College London.

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