What is the enemy of Great Barrier Reef?

Crown-of-thorns starfish is the enemy of the Great Barrier Reef. It is a large, starfish that feeds on coral polyps. When these starfish reach high densities, they can cause extensive damage to coral reefs. Outbreaks of crown-of-thorns starfish have been linked to human activities, such as overfishing and pollution, which have damaged coral reefs and increased the availability of food for starfish. Climate change, which has caused the ocean temperature to rise, has also contributed to outbreaks of crown-of-thorns starfish, as the warmer water stress corals and make them more susceptible to predation by starfish.