INTRODUCTION PHOTO ID

Effective marine conservation for threatened species relies heavily on information about that species and its population. This includes abundance and distribution of individuals and life history. In the past, this information has been collected using a capture-mark-recapture technique, this is a fairly invasive method and has its own disadvantages.

However, with the invention of the GoPro most divers now have access to easy to use underwater cameras which we can use to track our turtle and shark populations in a none invasive way. Both our sharks and turtles have areas of their body that can be used like fingerprints to ID them. These sorts of methods have become common place in tracking individuals over time.

This method has many advantages over tagging methods as its low cost and doesn’t directly affect the target species. While the ID itself can be time consuming the development of computer software makes it easy and accessible at home.

HOW DOES IT WORK

Profile pictures involved in this study are collect in two different methods: survey diving with the Gili Shark Conservation research divers, and local divers voluntarily donating pictures of sharks or turtles captured throughout the Gili Matra Marine Reserve. The Gili Islands is a tourist area and a diving hub of Indonesia.

There are over 40 dive centers on all 3 islands taking out hundreds of divers a day. By using these pictures we can grow our databases and have a more accurate idea of where the individual sharks and turtles are. During survey dives with the Research Team additional data is collected including sexing, any damage to carapace of body, and measurements: curved carapace length (CCL) and curved carapace width (CCW)

The photos are sent to us by e-mail (sharks@gilisharkconservation.com) or through the dive centres online Google drive and sharing network (gilisharks@gmail.com).

The Gili Shark Conservation Project Research Team has full access to the database and in charge of it’s correct coding and filing. Successful photographs are selected based on two main criteria:
1. Photographs of high quality (good lighting, in focus, no or very low glare).
2. Turtle: facial scale outlines clearly visible to the eye, shark: total side length and distinguishable markings clearly visible.

We use a computer assisted process using the coding of the facial profiles according to the portion and the shape of the blotches using photographs. The computer program is an easy to use photo recognition and pattern identifier that can give you the best result while limiting human error. As both profiles of the same individual display a unique blotch pattern, right and left profiles are analyzed separately for each individual.

If further photographs were taken of a correctly identified shark or turtle, those photos will be used as a reference and used for later analysis and storage. While you are with us you can be trained up on the photo ID software and can contribute to our overall knowledge of the individual turtles we see on a daily basis.

WHY IS IT IMPORTANT

The identification of individuals within a population and the collection of reliable information on distribution, habitat use, and life history traits are the basic requirement for behavioral and ecological studies of a species. Therefore, this long-term project is designed to provide valuable information to marine biologists around the world to help create better management strategies and educational outlets on the Gili Islands marine mega fauna.

The most endangered species found in the Gili Islands is the Eretmochelys imbricate (hawksbill turtle) which the IUCN states is “Critically Endangered”, and due to it’s common sightings throughout Indonesia is often neglected and mismanaged. The Chelonia mydas (green sea turtle) is also on the IUCN Red List as “Endangered” yet no strategies are currently in place throughout the region to conserve these creatures.

The Gili Islands boasts a large number of pregnant and juvenile reef sharks, however there is a lack of data geared towards population sizes and locations. Through this project, we hope to change the existing parameters of the Gili Matra Marine Reserve to identify and protect critical habitats from fishing and tourism to protect our marine mega fauna.

HOW CAN YOU BE INVOLVED?

You can be involved in our photo identification project in two different ways:

1. Join us at our base on Gili Air and take part in our programmes.
2. Adopt a turtle through our website. You can name the turtle, either green or hawksbill and receive updates on their whereabouts along with a species fact file and regular pictures of your turtle. This adoption allows us to be a visible presence in the water and aids us in protecting the turtles of Gili.

Special thanks to our data collection partner, Gili Shark Foundation and Gili Eco Trust.