Whilst sipping away on a Piña Colada, watching yet another glorious tropical sunset, have you ever stopped to think where your tropical beach comes from? Maybe this is far back in your mind, lazing away under a palm tree, but the answer may surprise you…
Those fine sandy beaches are not just created from millions of years of erosion as your high school Geography teacher may have you think. In fact, we can attribute entire tropical islands to a species of fish which is the bigger, uglier cousin (the cousin that you haven’t really met but you know served a couple of years in juvie for armed robbery) of Koh Tao’s very own Rainbow Parrotfish – the Green Humphead Parrot fish.
Both feast on the algae which grows on rocks and coral, problem is for a beast that can grow up to 1.3m is length is getting at it. The not so elegant solution nature came up with is that the combination of their razor sharp teeth, strong bite and incredible digestion system, mean that a school can devour entire coral reefs when coming to graze. They actually eat the rock and coral, process the algae for energy, and then excrete the unwanted rock in the form of fine sand. A single humphead can produce over two tons of sand a year, meaning that entire beaches and even islands are made up of the sand produced by this species.
Check this link out to see for yourselves…
left: Koh Tao’s rainbow parrotfish; right: green humphead parrotfish
It’s Koh Tao cousin may not be big enough to be responsible for the formation of Koh Nang Yuen, but if your diving around Twins or White Rock, you’ll see these green and pink fish nibbling away on the rock, and then producing a cloud of sand when they finish digesting, go for a dive tomorrow and check it out for yourselves.
So there you have it. The Beach Creator. The Coral Destroyer. Don’t let this put you off your Piña Colada though… the sand still feels amazing between your toes.
By Chris Nuttall