SEA TURTLE PHOTO IDENTIFICATION PROJECT

About the project

Over the past few decades, there has been a significant decline in global sea turtle populations. Human activities, such as tourism, have resulted in the degradation of nesting beaches. Additionally, the harvesting of sea turtles for their meat, eggs, and medicinal purposes, along with the unintentional capture of large sea turtles as bycatch in overfishing operations, has led to the majority of sea turtle species being classified as vulnerable or endangered. As a result, these population declines have spurred worldwide conservation initiatives that focus on researching population trends, implementing protective measures, and raising awareness to ensure the survival of these remarkable marine creatures.

Sea turtle photo identification project

In Zanzibar the size of the sea turtle population is still unknown. Meanwhile sea turtles are still hunted for their meat and eggs on a daily basis. This is why getting more information about the population is crucial.

Previous studies relied on standard ‘capture-mark-recapture’ methods based on tagging as a tool to establish population size. Our project relies on the photo-identification technique. This technique, increasingly used as a reliable tool to track individuals over time, has many advantages over tagging. Conventional tagging methods are costly. And they are stressful for the animals. The tags are difficult to apply and easy to fall off. Photo-identification offers high potential as it is non-invasive, low-cost and long-lasting.

A unique photo-ID code for every turtle

The unique and asymmetrical pattern of facial scutes on the cheeks of the sea turtles are like fingerprints. By adding photos of the turtles’ cheeks to a database, we identify individual sea turtles in a population and track them over time. The first step is collecting as many photos as possible. Next, we visually transform the photos into a unique turtle photo-ID code. Having an extensive database, we can ultimately estimate the population size and structure and gather reliable information on their distribution, habitat use and migration patterns. Besides this, we can determine the sex ratio in the population.