Acanthaster planci

Abstract

Acanthaster planci (family Acanthasteridae), also known by the common names crown-of-thorns sea star and crown-of-thorns starfish, is a large coral-eating asteroid that has gained notoriety due to the enormous amount of loss it can inflict on coral reefs and to its large population fluctuations (Fig. 13.1). A. planci occurs throughout the tropical and subtropical Indo-Pacific, from the Red Sea, Gulf of Oman and east African coast in the west, to the tropical eastern Pacific including the Galapagos, Panama coast, and the Gulf of California in the east. Its latitudinal limit is about ∼33° latitude north and south, being confined by the distribution of coral reefs. A. planci does not occur in the Atlantic Ocean. The asteroids typically have 14 to 18 arms and range from 20 to 40 cm in diameter, although individuals >70 cm in diameter have been recorded. They are covered with 4 to 5 cm long poisonous spines and contain several types of saponin toxins that act as anti-predatory agents (see Chapter 8). Depending on geographic region or diet, individuals are purple, purple-blue, reddish grey or brown with red spine tips, or green with yellow spine tips.