The crown-of-thorns starfish (Acanthaster planci) is one of the largest starfish in the world, and it is the scourge of the hard corals in the beautiful, colorful reefs of the Indo-Pacific and Australia.
The crown-of-thorns starfish even LOOK like scary baddies. Those are poisonous spikes in the photo below.
You wouldn't want that landing on your coral city like an alien spaceship.
The crown-of-thorns starfish can have up to 21 arms. With all those arms and a voracious appetite for coral (on which it feeds by spreading its stomach over corals and dissolving their polyps with digestive juices), they can denude a reef of every living coral, leaving just calcium carbonate crumbs leftover.
But never fear, reef keepers, the crown-of-thorns starfish has a nemesis!
The crown-of-thorns starfish's nemesis is the giant triton snail, genus Charonia. Watch is take down a crown-of-thorns starfish with a badass surfer-rock guitar soundtrack in this video from New Scientist.
Giant triton snails are the business. They're some of the biggest mollusks on the reef. The shell of Charonia tritonis can be over 2 feet long. These guys have a great chemical sense of smell, and sniff out their starfish prey.
"It sounds like something out of a sci-fi movie," says the news anchor, below. But the giant triton snail would be the protagonist, not the antagonist, in this hypothetical, we'd-totally-watch sci-fi film — because these bulky bivalves could save the Great Barrier Reef from crown-of-thorns starfish.
But there are few snails on the reef — giant triton snails are rare. So scientists are raising them.
They're being raised to be released onto Australian reefs for the express purpose of — erm, what's the nicest way of saying this? removing? mitigating? — crown-of-thorns starfish because the snail is one of the few animals that thinks the spiky coral-destroyer is yummy. Snail win.