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The big-beaked, rock-munching fish that protect coral reefs - Mike Gil

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As the sun rises over a quiet coral reef, one animal breaks the morning silence. Named for its vibrant scales and beak-like teeth, the parrotfish devours a particularly crunchy breakfast: rocks. Why would any creature take bites out of the seafloor? Mike Gil explores how these quirky and flashy foragers play a key role in defending the essential coral reef ecosystem.

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Parrotfish are odd-looking coral reef fish species that are specially adapted to chew on and eat rocks. Deploying large, multi-video-camera systems in coral reefs, scientists are spying on parrotfish and analyzing their behavior with the help of artificial intelligence. Could these data help us understand how to better protect coral reefs?

Coral reefs are complex ecosystems that house an incredible amount of biodiversity and provide vital services to humankind. This makes coral reefs pressing and fascinating, though challenging study systems for researchers to probe to understand how nature works, particularly in the face of anthropogenic (i.e., human-driven) environmental change.

We remain at the forefront of our understanding of just how interconnected life in coral reefs may be. We know that the transfer of energy through trophic interactions (who eats who; e.g., herbivory, predation) plays a critical role in driving feedback loops that shape the communities of fishes and invertebrates that we see when we visit a coral reef. However, recent research suggests that a second, more hidden currency likely also plays a critical role: information.

Every cubic foot in a healthy coral reef is bustling with life forms that have evolved to use information from the environment to inform their decisions in the vicious quest to survive and reproduce. Much of this information can come from surrounding life forms, including different species. For coral reef fishes, including the peculiar, sand-pooping parrotfish, scientists are in the midst of developing tools (like the invention and deployment of this video camera array) to carefully measure what information is being shared both within and across species; for example, marine biologists have used algorithms from video games to measure exactly what fish see — including neighboring fish — before they decide whether to flee from a threat!

Importantly, researchers are also rigorously investigating what these social interactions mean for the greater ecosystem. So far, this work has revealed that reef fish social networks appear to make individual fish bolder and more likely to feed in dangerous areas of the reef exposed to predators, like sharks and barracudas (see this TED talk for more information). At the ecosystem level, this suggests that coral reefs may be more vulnerable than we thought, because reducing the abundance of fish populations (e.g., through unsustainable fishing practices) not only reduces how many fish are left to control algae but this could also make remaining fish more timid and less effective at controlling algae.

But the importance of understanding how animal social networks can shape ecosystems is far from limited to coral reefs. Modern technologies are suddenly allowing us to understand animal behavior at an unprecedented scale and resolution, and with these insights, we will be better equipped to inform conservation and management efforts to sustain natural ecosystems like coral reefs for future generations (see this TED-Ed video about coral reef management plans).

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TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

Meet The Creators

  • Educator Mike Gil
  • Director Franz Palomares
  • Narrator Addison Anderson
  • Illustrator Tara Sunil Thomas
  • Sound Designer Carlos Palomares
  • Composer Carlos Palomares
  • Director of Production Gerta Xhelo
  • Editorial Director Alex Rosenthal
  • Producer Bethany Cutmore-Scott
  • Editorial Producer Dan Kwartler
  • Script Editor Alex Gendler
  • Fact-Checker Julia Dickerson

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