Sea Turtle Population Monitoring/Sea Turtle Photo Identification
All sea turtle species are more or less endangered. If you want to get some more detailed information about this, you have to answer the following question:
How many individuals of a certain species live in a defined area?
In other words, you have to identify the species of the observed sea turtles and count the individuals for each species. But how do you do this?
First, you need to be able to identify the species of the observed sea turtles. This is relatively easy for experienced sea turtle observers, as long as it isn't about very young turtles, but can develop into a really difficult task for beginners.
Here's some help, a sea turtle identification key, provided by the Sea Turtle Conservancy, Gainesville, Florida:
When you know now how to to identify sea turtle species, how do you distinguish between different sea turtle individuals of the same species? Size and sex are of very limited value, because the size is dependent on the age of a turtle (Imagine you have three different sea turtles of same species, almost the same age and same size in your area!) , and distinguishing between males and females is only possible after they are at least 20-25 years old.
The key for accurate ID is something else: The facial pattern on both sides of the head is unique for every single turtle. This means: Two different sea turtle individuals will show two different facial patterns.
Let's look at the following example: You see two pictures of hawksbill sea turtles, both pictures are from the Maldives. Task: Do they show the same turtle, or do they show two different turtles?
Confused whether this is the same turtle or not? We now show you the same pictures again, but with some facial parts marked with white lines.
Now it's easy to see that the pattern within the marked sections is different! So the two pictures show two different hawksbills and not the same!
If you like to learn more about sea turtle photo identification, visit the following link to Olive Ridley Project: Turtle Photo-ID – Tracking Turtles Through Images
It should be clear now: What you need to do is taking good quality pictures of both sides of the head of each sea turtle you meet. This is not always feasible, turtles can be quite shy, but you need at least one picture from one side of the head, right or left.
You should further note date, time and location of your sea turtle observation. Most accurate regarding the location information is using GPS coordinates, if available, if not, try to describe the location as accurate as possible.
You can now start to record your sea turtle sightings, using an Excel sheet, for a bigger project a database is certainly a better option.
Your first well-documented sea turtle is your first entry into your recordings, for the second (and any following) observed sea turtle of the same species the situation is different: You have to check whether it is the same turtle of your first observation or not. If it is not found the same individual after comparing the facial patterns, it will get an entry as a new individual.
Here's a possibility to document your observations with an Excel sheet:
It is practical and time saving to use ID software for comparing the sea turtle facial patterns. One possibility is I3S Pattern ID software (Link: https://reijns.com/i3s/i3s-pattern/ ), a free software designed by a small team in the Netherlands.
What we recommend to all who observe turtles during recreational diving or snorkeling: Be active as a citizen scientist and share your pictures and observation data with a local scientific sea turtle project!
Generally, sharing these data is very much appreciated and of great value for scientific long-time monitoring of sea turtle populations.
Here's how you can share your data with the Olive Ridley Project, regarding sea turtle observations in the following countries: Kenya, Maldives, Seychelles, Oman.
What the Olive Ridley Project needs:
Email contact for sharing your observation: email@example.com
When you observe sea turtles in another country, you can share your observations (The requested kind of pictures and type of data are the same!) directly to the following platform: Internet of Turtles
Your data will help scientists to get better insights into the spatial distribution and temporal changes of sea turtle populations in a certain region, to monitor the conservation status of these endangered animals and will enable them to develop and recommend precise protective measures to local administrations and government institutions, measures which fit to local conditions.