Crown-of-thorns starfish (Acanthaster planci) is a starfish that has between 8 to 21 arms from the central disc. They have large and venomous spines that protect them when they are eating out in the open. An Acanthaster planci primary diet consists of hard corals. Each day, 478 cm² of live coral can be eaten by an average size adult of 40 cm. Acanthaster planci is said to have a role in creating a diversity habitat, as they create bare areas of coral rock that are available for new settlement and recruitment of other species of sessile invertebrates. But if coral cover is drastically reduced, animals that depend exclusively on coral cover for food and shelter may decrease. So, the impact of Acanthaster planci in their environment depends on how abundant they become (Glynn, 1976 Keesing and Lucas, 1992 Wilson, et al., 2008).

The phenomenon of Acanthaster planci outbreak is when there are too many Acanthaster planci in an area that ends up making the existence of coral scarce. The population outbreaks of Acanthaster planci can possibly result in up to 80% mortality of corals (Pratchet et al, 2014).  The causes of this outbreak vary from one area to another. It is still not known for certain about the impact of human activity related to Acanthaster planci outbreaks.

A solution for this Acanthaster planci outbreak is by injecting a type of chemical into Acanthaster planci body, in which it will die by it self. But since injecting chemical is a rather costly method, a price saving method that was created is to capture Acanthaster planci where they are then buried on land.  The later method is also very useful to prevent the outbreak.  However, due to very huge coral reef locations and with very limited resources, regular observation on Acanthaster planci population is focused on tourist destination.