By Stacey Venzel
If you find yourself cooped up in front of a fireplace this holiday season pouring out your woes, unable to traverse the pristine white sand beaches acclaimed throughout the world, you might want to rethink your disappointment. Those barefooted, swimsuit-clad friends of yours are actually walking and luxuriating on parrotfish poop.
That’s right, the planet’s coveted white sand coastlines are made up of fish feces. Parrotfish reside in reefs where they gnaw on algae that grow on coral. Their beak-like mouths have two rows of small teeth to scrape off the algae. In fact, if you’ve ever been snorkeling, you’ve likely heard the crunching noise associated with their foraging behavior. Without parrotfish to keep the algae growth under control, coral reefs would be in further peril than they are today with climate change, as would coastal vacation destinations throughout the world.
Inevitably, some coral makes its way into the parrotfish’s digestive tract when it’s munching on an algal meal. The fish have an extra set of teeth in their throat—called pharyngeal teeth—that grinds the coral into sand. Coral, composed of calcium carbonate, creates carbon dioxide when mixed with acid, such as acidic stomach juices. This bubbly concoction creates a lot of gas. But parrotfish lack a stomach, and, therefore, do not have this chemical reaction inside of them. That makes these marine creatures experts at simply extracting nutrients from the algae and excreting the unnecessary, ground up coral.
Mathematicians at the University of Hawaii estimated that there are seven quintillion, five hundred quadrillion grains of sand out there—that we can see. That’s a lot of sand, which also means a lot of fish poop. A large parrotfish is estimated to excrete about 840 pounds of sand annually. In reef-ridden regions like Hawaii where schools of parrotfish thrive, that amounts to hundreds of tons of sand each year.
In the Maldives, parrotfish poop makes up 85 percent of the sand surrounding the reefs. Their excrement has even accumulated enough to form small islands, creating a dotted island chain resembling a necklace in satellite feed. With rising sea levels, the parrotfish’s “superpower” has become increasingly more important; they’re masters at making islands in the middle of the ocean!
A few other species are worthy of mentioning in their excretory contributions to sand, though none create as much sand dung as the parrotfish. Sea urchins also graze on coral algae with their five-pronged dental arrangement, a set-up so unique it has been given its own name: Aristotle’s Lantern. Sponges, oysters and some marine worms contribute a portion to the production of sand. Weathered shells and rock play a small role in the creation of beaches, especially in regions with coarser, less appealing sand. Bermuda’s pink beaches are composed of ground up coral, too, but the pretty rose coloring is thanks to a red-tinted foraminifera protist. Some sandy stretches in places like Hawaii are even black, composed of volcanic glass. But for the most part, those beautiful, ivory coasts are a collection of parrotfish poop particles.
So if you find yourself dodging snow this winter instead of digging your toes into one of the world’s top beaches, privy yourself to a wry smile. Because now you know your vacationing friends are trotting through poop.
- Simon, Matt. “Absurd Creature of the Week: This Goofy Fish Poops Out White-Sand Beaches.” Wired. August 8, 2015. Web Accessed December 7, 2015. http://www.wired.com/2014/08/absurd-creature-of-the-week-parrotfish/
- Cave, James. “Hawaii’s White Sand Beaches Are Made From Parrotfish Poop.” Huffington Post. March 29, 2014. Web Accessed December 8, 2015. http://www.huffingtonpost.com/2014/03/29/hawaii-beaches-parrotfish-poop_n_5052935.html
- Meyers, B., Rosen, J. & Augenbraun, E. “Parrotfish Poop Makes Beautiful Beaches.” Scientific American. June 10, 2015. Web Accessed December 7, 2015. http://www.scientificamerican.com/video/parrot-fish-poop-makes-beautiful-beaches/
- “Sea Urchins’ Teeth and Aristotle’s Lantern.” The Living Coast. February 19, 2015. Web Accessed December 7, 2015. http://www.thelivingcoast.org/sea-urchins-teeth-and-aristotles-lantern/
- Castro, Joseph. “What is Sand?” Live Science. May 28, 2013. Web Accessed December 7, 2015. http://www.livescience.com/34748-what-is-sand-beach-sand.html