What eats crown-of-thorns starfish?
Natural predators of crown-of-thorns starfish include the giant triton snail, some pufferfish and triggerfish, the humphead Maori wrasse, and certain shrimps and worms that eat their young.
The giant triton is a large sea snail with a beautiful shell. It hunts starfish, injecting saliva that paralyses them. Tritons were heavily collected for their shells in the past, and some scientists think this may have contributed to outbreaks.
Fish such as the starry pufferfish and the titan triggerfish can attack adult starfish, while many small reef animals eat juvenile starfish and larvae. Scientists have found that predators of juveniles may play a key role in controlling numbers.
Using predators to help reefs
Researchers have studied whether the smell of giant tritons can keep starfish away from reefs, and are investigating breeding tritons.
Studies have found that outbreaks are less common on reefs closed to fishing, suggesting that healthy fish populations help keep starfish in check.
Divers also remove starfish directly by injecting them with vinegar or bile salts, which is currently the most effective tool on high-value tourism and research reefs. Scientists combine this with monitoring to catch outbreaks early, when starfish numbers are still small enough to manage.
Did You Know?
Crown-of-thorns starfish can regrow lost arms, making them hard for predators to kill.