The picturesque white sand beaches of Redang have long been a popular draw for tourists. - Photo courtesy of Mukherjeesaikat (CC BY-SA 3.0)
LOVED by tourists and locals alike, Malaysia boasts many beautiful white-sand beaches, especially on the east coast of Malaysia and in Sabah.
From the islands of Redang and Perhentian to Sipadan and the Tip of Borneo in Sabah, travellers flock to our beaches and fall in love with its beautiful powder white sands.
While people bask on the beach enjoying the sun, sea as well as the aforementioned sand, not many deign it necessary to get to the bottom of where all the sand comes from.
Apparently, a vast majority of the white powder sand we enjoy on the beach is the result of fish interacting with its surroundings.
Is it true that white sand beaches are made by fish?
Verdict:
TRUE
Yes, it is true that for the most part, white sand beaches are made by one family of fish, the parrotfish.
Before we get into how parrotfish (or rather, what they "get out") we have to understand what sand is.
Essentially, most sand is just rock or mineral that has been ground down through natural processes to a particle measuring between 0.0625mm to 4.75mm. Anything larger is considered gravel, anything smaller is silt.
The sand that's left will usually maintain the characteristics its "parent" material had.
Bali's black sands are the result of the weathering volcanic material from its Gunung Agung, such as basalt and obsidian (the stuff that killed the White Walkers in Game of Thrones).
On the other hand, some of the islands of the Bahamas boast pink sand beaches which are actually the ground-up shells of a type of marine microorganism called Foraminifera. Not as effective against White Walkers, but pretty nonetheless.
Going back to our white sand beaches, where do they come from?
They are the result of the constant grazing of Malaysia's 27 species of parrotfish.
Parrotfish have a particular type of diet, they eat coral. Specifically coral polyps and the algae that grows within the corral.
A Rusty Parrotfish swimming among the corals. Parrotfish get their name from their beak-like mouths that they use to pulverise coral with. - Photo courtesy of Diego Delso, delso.photo, License (CC-BY-SA)
Now, coral polyps are delicate little animals that are mostly filter feeders who live in huge colonies along our coastline.
Just in case you aren't aware, coral polyps encase themselves in a hard rock-like exoskeleton made of calcium carbonate (essentially limestone).
This does not make for easy eating for the parrotfish. These colourful fishes have had to evolve one of the hardest sets of teeth in the animal kingdom along with one of the strongest bites just so that they can eat dinner.
Parrotfish graze on the coral in much the same way as cattle graze on grass and are more or less eating throughout the day.
While you would think their dietary requirements would be detrimental to the reef, they actually fulfil a vital role in their ecosystem. Along with the coral polyps they continuously munch on, they also nibble on algae and other microorganisms that are far more dangerous to the reef.
As for where the sand comes from, well, after chowing down on some coral, everything passes through the fish.
Seeing that calcium carbonate is not digestible in the least, it comes out the other end as the fine powder sand that blesses our beaches.
Seeing as one large parrotfish can excrete as much 450kg of sand a year, if not more, and these fishes swim in shoals, our beaches will always be topped up with fresh white sand just as long as we keep the coral reefs around them healthy.
References:
1. https://oceanservice.noaa.gov/
2. https://oceana.org/blog/make-
3. https://ocean.si.edu/ocean-
4. https://www.talkaboutfish.com/
5. https://www.
6. https://www.bahamas.com/
7. Glossary of Terms in Soil Science, Agriculture Canada (1976) ~ pdf (sis.agr.gc.ca/cansis/
