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Beach = parrotfish shit

This is the dream, isn't it? White, sandy beach. Clear waters. Beautiful skies. It's almost picture perfect. 
(Ok, to be honest, I'm not a big fan of beaches... but let's all live in the cliches for a little bit)

Here's the thing though. This beach is in Hawaii. And Hawaii has very little terrestrial sand. It's a naturally sandy place. So where did all this beautiful sand come from?

No one explains this any better than Ling Ong, a marine biologist with Hawaii's SWCA Environmental Consultants: "Almost all of our sand is of biological origin; I like to tell people that the sand you're standing on in Hawaii has probably gone through the gut of something. It'll have gone through the gut of a parrotfish, a sea urchin, some kind of worm.”

Doesn't that give you a warm feeling to match the warm weather in the photo? 

Hawaii Tourism Authority (HTA) _ Tor Joh

Photo credit: Hawaii Tourism Authority (HTA) / Tor Johnson

This fella in the picture - the giant bumphead parrotfish is the main contributor to many of the white sandy beaches we love and roll around in. The parrotfish is really a remarkable creature with several seemingly unbelievable characteristics. 


How does it produce sand? Well.... parrotfishes have a diet of, get this... coral. It eats not only the hard skeleton of coral, rich in calcium carbonate but the soft-bodied organisms (called polyps) that cover the skeleton, as well as the algae (called zooxanthellae) and bacteria living inside the coral skeleton.

It does so using its distinctive forehead to bump off loose coral to munch on

See the white bit sticking out from its mouth? That's the parrotfish's teeth. And what a formidable set of teeth it is. Each parrotfish has roughly 1,000 teeth, lined up in 15 rows so close together that it forms a beak-like structure, which they use for biting into the coral. Parrotfish teeth are made of a material called fluorapatite - the second-hardest biomineral in the world. It is harder than silver or gold!


So strong bumping forehead. Strongest teeth. Something has to give. The parrotfish has no stomach! They simply gnaw off the coral and grind it up with teeth at the back of their throat. The nutritious algae is absorbed by their digestive system while it fires out (i.e. shits out) calcium carbonate as sand.

In a year, one large parrotfish can produce up to 800 - 1,000 pounds of sand. Talk about productivity.

Parrotfishes play a vital role in marine eco biology. Algae is a major threat to corals, covering them and cannibalising on precious light. While parrotfishes do pry away some coral, they play an important role in keeping algae in check. Not only do they remove surface algae which takes up the most light, but some species have also evolved to gnaw below the surface, to reach algae that had penetrated the coral. Corals are the centre of the ecosystem in the oceans, and parrotfishes play a vital role as the coral reef's trusty and indispensable gardener. 

However, parrotfishes face a heavy threat from hunting, due to its large size and... well peculiar sleeping habits. As with its head, its teeth, its diet, and its produce, parrotfishes tend towards extremes. The parrotfish is an incredibly heavy sleeper. They don't wake up easily, making them very easy to hunt. It's also a major problem that it tends to be the larger parrotfishes (more meat) that are the most heavily hunted.

The parrotfish has one more unique characteristic. They are sex-changers. Parrotfishes are all born female. The fishes form into schools. When they mature, the largest female in each school will change into male and assume command over the school. So you know, what were previously her sisters and relatives now become... his harem. You can tell the difference between males and females by colour - females (like the one in the photo above) are dull-coloured, while males are brightly-coloured. Since the largest fishes are the sole male or the most productive females, the hunting of these fishes causes a serious dent into the population of parrotfish.

Let us all work together to save this incredible fish - a sex-changing, hard-headed, coral-saving, sand-producing fish with a real bite. Our marine ecosystems have been heavily damaged by climate change (caused by humans), and further worsened by over-fishing and the dumping of wastes into our seas and oceans. There are such wondrous life in the seas - let us not be the ones to ruin it all. 

NOAA national ocean service.jpg

Photo credit: National Ocean Service, NOAA, USA.

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