When I first read about sea turtle photo identification, I was really excited because it provides an opportunity to study more about the sea turtles at Perhentian Islands. There is a lack of research done on sea turtles here, hence a paucity of data about the population around these islands. Moreover, tagging has not been practised for more than a decade.
Photo identification is a reliable method of identifying every individual turtles. Each turtle has unique facial scale and spot patterns on both sides and these features are visible on photos. It is less invasive to sea turtles as no physical contact is needed. Moreover, tagging only studies the nesting females on the beach but photo identification enables the study of both juveniles, male and female adults at nesting beaches and feeding grounds in the sea. Even if a turtle loses its tags, it is still possible to identify the individual through its face. It also enables the understanding of sea turtle habitat use around the islands. More interestingly, the locals and tourists can participate in the study as many take sea turtle photos when they encounter one. Of course, this is all possible if the photos are clear and sighting data such as date, time and location the photos are accurate.
Out of curiosity, I started looking for sea turtle photos that I have and looked at the facial scale patterns of these turtles. True enough, it is actually possible to identify each and every one of them! Hence, the Perhentian Turtle Project was set up in hope to better understand the sea turtle population size here. As some turtles were seen more than once and for a few years, I realised photo identification is not merely about identifying individuals and knowing their movements. It also enables us to monitor their progress, more of like every photo taken of the same turtle at different times shows how the turtle is at a particular time.
For example, we saw P15F for the first time in May 2012. The next recorded sighting of P15F was in August 2014 and the photos showed a cracked shell, which looks like boat strike. However, lucky for the turtle, it survived and the injury healed. The scar is visible on photos taken in May 2015.
P15F, a female adult green turtle first seen feeding in 2012
When P15F was sighted again in 2014, it had a cracked shell
In 2015, P15F was seen with a scar on its shell that showed a healed injury from boat strike
Unfortunately, P5F, an adult female green turtle, suspected to be hit by boat, may not be that lucky. The first photo of P5F was taken in 2012. In 2013, it was seen having tags on both of her front flippers. After zooming in the photos, the tag numbers showed 5911 (left) and 5912 (right). They were tags from SEATRU (UMT Sea Turtle Research Unit). SEATRU confirmed that P5F was tagged in May 2013 and up to July that year, she laid 9 nests at Redang Islands. It was seen again in September 2013 at Perhentian Islands. It has been around since. It is one of the tame turtles that don’t mind having snorkellers watching it feed. Sadly, when it was seen on 8th September this year, it had a huge crack at its shell. She seemed to be feeding like normal, only God knows how it felt. The crack looked severe and I can only hope it survives the hit and continue to live and breed. It has not gone back to Redang Islands to nest since 2013. If it survives, it may still in the future lay more nests. Most feel for injured animals. In this case, P5F is not just an animal. As it is frequently seen, it feels like I know P5F, which is why the more heartbreaking it is to see this happening to it.
P5F was first spotted in 2012
One year later, it was seen around Perhentian Islands with tags at its front flippers
Recently, P5F was seen with a really bad cracked shell
Every adult female can lay on average of 100-120 eggs, between 2-10 nests a breeding season. Most conservation efforts are put into protecting the eggs and hatchlings because sea turtles have a very high mortality rate when they are young. It is believed only 1 in 1000 to 10000 hatchling survive to adulthood. It takes them an average of 25 years to become sexually matured. The fact that only that small number of hatchlings will make it to adults makes it more important to increase protection measures to protect these adult turtles so that they can continue to breed.
Boats are one of the main threats for sea turtles at Perhentian Project. There are many identified turtles with injuries and scars from boat strike. Some survived, some didn’t. So far this year, the project received 3 reported death of sea turtles. 2 had decomposed and were beyond identification. Meanwhile the other one was not found on the database, meaning it has not been spotted anywhere in the water or on the beach.
Malaysia has started using TEDs to reduce turtle bycatch which is also one of the main threats to sea turtle besides turtle eggs consumption. What about threats from boat propellers? To come up with mitigation measures, that everyone agrees to, is always the hardest part. Everyone acknowledges the problem and when it comes to solutions, there are conflicts. To entirely protect the feeding grounds by not allowing boat traffic is not entirely impossible but locals would disagree because their livelihoods depend on bringing tourists to these areas to see turtles. To enforce a rule that every boat needs to slow down the speed of their boats at feeding grounds needs continuous monitoring which requires manpower that the authorities involved lacks of. Maybe a boat propeller cover can be a solution, as long as it doesn’t affect the speed and fuel usage of the boat.
However, the mortality of juvenile or adult sea turtles is increasing in an alarming rate. Is it really enough to only increase the efforts on nesting beaches without taking more protection measures to mitigate threats to sea turtles in the ocean?
The project is new and we only have photos from 2011. An on-going photo identification research allows a better and more comprehensive understanding of the sea turtle population, their habitat use and movement around these islands. Any turtle photos taken, even from previous years, can be submitted to the project for identification. Conservation efforts can be improved with a strong and sound understanding, which is what the project is trying to achieve.