This year on the gulf has been a relatively ‘cool’ one, if I can call it that! We have experienced lots of wind and rain, but we are finally getting some consistent sun and the diving conditions are becoming wonderfully clear once more, making our conservation dives all the more relaxed, and also making finding cool critters even easier.
Did you know that there are many marine creatures that we can identify to an individual level? I would love to tell you how to go about this, and I will focus on three animals in particular; Turtles, Manta Rays and Whale sharks.
You may wonder why we would want to identify these animals to the individual. Well, marine animals are incredibly variable in their ecology and there is a great deal of difference between how much we actually know about each. Some we have abundances of information on, and others we hardly know anything!
The Whale Shark is a good example of this, where only a couple of young individuals/pregnant females have been observed providing us with some, yet still very little about these varying stages of their lives. For any species of animal though, whether we know lots or little about it can be better understood if we have a grasp on population dynamics, migrations, mating grounds and individuals whereabouts.
For example, here on Koh Tao there is a Turtle identification project which allows us to understand how many turtles actually live in these waters, if new turtles come to the area, and to be able identify individuals which have died and washed up on beaches.
This same can be applied to other animals that we want to understand more about, to broaden our scope of their general habitat, what their population is like and perhaps how we can go about conserving their species.
So! How do we go about this process? Well, it’s actually rather straight forward. Let’s start with turtles.
Most of us probably hadn’t taken much notice to the shape of the scales on the sides of sea turtles faces, but the shapes these take are actually completely unique to each individual. Most of us probably can’t remember the exact patterns their faces have, so taking images is really useful!
These can be layered up next to images of previously documented individuals to see if there are new turtles in an area or to see if they are moving around a lot (if you have many different images from many occasions).
Previously to estimate turtle population sizes, tag and release programs have been used, and while they can be effective by giving individuals colours or numbers, there have been many problems with tags being lost, partially destroyed or covered over by other marine organisms.
This method is easier and certainly the less invasive alternative!
How about mantas?
For these guys, we ignore the face area. They have rather strangely shaped faces compared to many animals anyway! To identify manta rays we must look at their bellies, which each will have black and white patterns or ‘splotches’ splayed across them. I was lucky enough to learn a bit about this and get involved with a bit of manta ray identification work when I was over in Western Australia last year.
There is such massive variation between the complexity and patterning of their bellies, so many different pattern ‘types’ were developed to group mantas into smaller groups in a database, as the region that photos were coming in from had had sightings of hundreds of these awesome elasmobranchs (the cartilaginous fish, such as sharks and rays).
This method certainly helped, but it is still a time consuming (yet still very cool) process.
Lucky last, how do we identify the biggest fish in the sea (Whale Sharks are indeed the biggest, and ironically are filter feeders like many whales!)? If you’ve been lucky enough to encounter a Whale Shark you would have probably noticed that they are quite spotty animals, and have a few stripes and crooked lines chucked in amongst their patterning too.
This is where the magic happens! Specifically, the area above the left pectoral fin is where the magic is for identifying purposes. Like in turtles and manta rays this area on the body when compared to other whale sharks is like a fingerprint.
The left side is chosen to make identification a simpler process. For an animal so large, there is very little known about these animals so really, any new information is good information.
If you’re ever out and about in our ocean, and stumble across any of these animals you can be a part of citizen science projects. Here on Koh Tao, there are facebook groups called ‘Koh Tao Turtles’ and ‘Koh Tao Whale Sharks’ that request photos from the general public when they have encounters, so the images can be used to identify the individuals. Whale sharks also have a global citizen science project, where you can submit photos to a website called whalesharks.org.
Science is sweet, and it’s cool to get involved. I hope you all enjoy identifying some sea creatures in your futures!
‘Til next month xxx