Tag: Crown Of Thorns Starfish (Acanthaster Planci)

Growing to a maximum diameter of around 40cm, the Crown Of Thorns Starfish (Acanthaster Planci) is the second largest starfish in the world, and almost certainly the most notorious.

The Crown of Thorns is a voracious predator of Coral Polyps (the correct term being "coralivore") and can, in times of increased population, cause massive damage to reef structures.

However, when populations are in balance with their surroundings, the Crown of Thorns plays an important part in inhibiting the overgrowth of faster growing coral species, allowing some of the slower growing species time to gain a foothold.

In local waters, the Crown of Thorns is almost always a slate gray colouration (a dark purple variation is common in many areas), with clusters of small red-ish spots called papullae between its long venomous spines.

The Crown of Thorns has very few natural predators due the venomous spines, making careful monitoring of its numbers a matter of importance.

Growing to a maximum diameter of around 40cm, the Crown Of Thorns Starfish (Acanthaster Planci) is the second largest starfish in the world, and almost certainly the most notorious.

The Crown of Thorns is a voracious predator of Coral Polyps (the correct term being "coralivore") and can, in times of increased population, cause massive damage to reef structures.

However, when populations are in balance with their surroundings, the Crown of Thorns plays an important part in inhibiting the overgrowth of faster growing coral species, allowing some of the slower growing species time to gain a foothold.

In local waters, the Crown of Thorns is almost always a slate gray colouration (a dark purple variation is common in many areas), with clusters of small red-ish spots called papullae between its long venomous spines.

The Crown of Thorns has very few natural predators due the venomous spines, making careful monitoring of its numbers a matter of importance.

Alan's picture
Crown Of Thorns Starfish (Acanthaster Planci)

Another close-up of the infamous Crown Of Thorns Starfish (Acanthaster Planci). This individual was just one from the few seen during a single dive at Shark Island, Koh Tao.

Alan's picture
Crown Of Thorns Starfish (Acanthaster Planci)

A close-up of the venomous spines and papullae (the small red spots on the skin) of the Crown Of Thorns Starfish (Acanthaster Planci).

Alan's picture
Crown Of Thorns Starfish (Acanthaster Planci)

The notorious Crown Of Thorns Starfish (Acanthaster Planci) appears, thankfully, to be present in numbers which do not pose a considerable threat to local reef systems.