The Manta has got to be one of the most breathtaking creatures on the planet to dive with. The manta ray is a real bucket-list item for all divers all around the world. Once commonly seen here on Koh Tao, there hadn’t been a confirmed sighting of a manta for a very long time but over the last 10 years or so they do seem to be getting witnessed a lot more especially over the last couple of years or so. And yesterday we were very lucky to encounter one at Southwest Pinnacle.
With the diving community absolutely ecstatic over the magnificent manta that paid us a visit, there’s never been a better time to look more closely at these creatures, and investigate what may have brought it here.
So what do we know about the manta ray?
There are 2 species of manta rays: the reef manta (Manta alfredi) and the giant manta ray (Manta birostris). Both are classified as “vulnerable” in the Red List of the International Union for Conservation of Nature, unfortunately. They have the largest brains of all fish apparently, which doesn’t explain why it’s been so long since they came to Koh Tao the ignorant shits.
Fish you say? That’s right, just like Nemo and Dory manta rays are in fact fish, just funny-looking ones. They are actually related to sharks, but are considered gentle creatures which do not represent a significant threat to humans, plus they lack the venomous tail spikes that many of their relatives have.
The largest species is the giant manta ray, whose central disc can measure up to 9 meters wide! Despite their massive size mantas eat only tiny little plankton, which they filter through their gills with something called ‘gill rakers’ – widely sought-after in Chinese medicine due to the ridiculous belief that it can heal anything from colds to cancer. Yeah right China, keep your filthy mitts off them!
So what brought them to us again?
Manta rays are distributed in tropical, subtropical and temperate oceans worldwide. They’re not fans of cold water at all, and with water temperatures on Koh Tao averaging around 30 degrees all year round the conditions are perfect for them to come and say hello!
As plankton eaters, it’s actually quite surprising that we haven’t been seeing them a lot more than one every million years or whatever it is – after all the ocean around Koh Tao is often full of plankton, which is the main reason why we have so many whalesharks visiting our waters all year round.
Could the recent anoxia event (complete lack of oxygen) we’ve been seeing at depth have something to do with it? It’s certainly possible, but I believe the most likely conclusion is that we’ve had an extra-long influx of planktonic matter this year, likely coming from the depths of the South China Sea – when the food comes, the hungry follow. This would also explain the numbers of whalesharks we’ve been seeing, and also the amount of salps and comb jellies we’ve been finding on every dive site and shoreline.
I’d love to be able to say these magnificent mantas are back for good, but only time will tell. Watch this space, and if you’re not already a certified diver then hurry and do something about it soon! Contact Big Blue Diving to see how you can get certified.