Photo-Identification Research Method to Identify Sea Turtles on an Individual Basis
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Sea Turtles 911


volunteer takes photos of wild sea turtle at a beach in Hawaii Sea Turtles 911 volunteer takes photos of a wild sea turtle in Hawaii, where turtles exhibit an unique basking behavior.

Tagging turtles for mark-recapture studies allow us to identify individuals and estimate the population size. Traditionally, physical objects, such as metal tags, are attached onto the turtle's flipper by piercing through the soft skin, which causes discomfort to the turtle and hazards to the researcher, as referenced on pages 7-8 in Factors to Consider in the Tagging of Sea Turtles.

Since animal welfare is very important to the mission of Sea Turtles 911, we do NOT want to capture and restrain animals to tag them with physical objects, as many institutions do. As a volunteer for Sea Turtles 911, we are always advised to use minimally-invasive methods to collect data on sea turtles without disturbing them. This is why we use the photo-identification method to tag turtles without even touching them physically; think of this as tagging your friends on social media to identify them digitally! From a distance, we take photographs of a sea turtle in order to survey the local population. By collecting many photos of turtles, we continue to build a database with thousands of photos and utilize an automated recognition software to identify sea turtles on an individual basis. The more photos we have, the better our software will be at identifying individual turtles; in this way, we indirectly track the turtles non-invasively, learning more about the population and the factors affecting their behavioral ecology. As we determine how many individuals there are in the local population and the potential threats they will encounter, we can communicate the science to other researchers, so we can advise policymakers and the public to make more informed decisions on environmental conservation plans and laws protecting sea turtles.

After reviewing the following research publications for more information on how to identify sea turtles through photo-identification, please write one reflection on what you learned and found the most interesting. The purpose of the writing is not to summarize the content, but to reflect on how this new information has made you more aware and/or more curious. We expect your reflection to be 300-500 words in length, but can be more if you have more to share or ask.

Research Publications on How to Identify Individual Sea Turtles by Photo-Identification:

  1. Leslie (2016) The Internet of Turtles

  2. Dunbar (2015) Picture Perfect Photography for Turtle Monitoring.

  3. Dunbar (2020) HotSpotter: Using a computer-driven photo-id application to identify sea turtles.

  4. Dunbar (2014) Recognition of juvenile hawksbills Eretmochelys imbricata through face scale digitization and automated searching.

  5. Gatto (2018) A novel method for photo-identification of sea turtles using scale patterns on the front flippers.

  6. Carpentier (2016) Stability of facial scale patterns on green sea turtles Chelonia mydas over time: A validation for the use of a photo-identification method.

  7. Su (2015) Applying a fast, effective and reliable photographic identification system for green turtles in the waters near Luichiu Island, Taiwan.

  8. Schofield (2008) Investigating the viability of photo-identification as an objective tool to study endangered sea turtle populations.

  9. Reisser (2008) Photographic identification of sea turtles: method description and validation, with an estimation of tag loss.

  10. Long (2017) Using Photographic Identification To Monitor Sea Turtle Populations At Perhentian Islands Marine Park In Malaysia.

  11. Chew (2015) Photographic Identification of Green Turtles (Chelonia mydas) at Redang Island, Malaysia.

  12. Carter (2014) Automated marine turtle photograph identification using artificial neural networks, with application to green turtles.

  13. Hall (2013) Inferring Sea Turtle Recapture Rates Using Photographic Identification.

  14. Lloyd (2012) Methods of Developing User-Friendly Keys to Identify Green Sea Turtles (Chelonia mydas L.) from Photographs.