Acanthaster planci on the Great Barrier Reef
The organism Acanthaster planci, commonly known as the crown of thorns starfish, has a drastic effect on the health of coral reefs all over the world, including the Great Barrier Reef of Australia. This poisonous echinoderm feeds upon the coral, and although this should be a healthy and natural part of the ecosystem, the population explosions of the starfish have caused devastation in many portions of the Great Barrier Reef. Reef sections take anywhere from ten to fifteen years to recover, and some never recover completely with the same species distribution. The starfish outbreaks seem to travel southward down the reef with the two primary outbreaks reported in the last 40 years both beginning around Green Island and ending between Cairns and Townsville. The cause of these outbreaks is still unknown. They may be natural phenomena occurring throughout history, or they may be caused by human influences. The most effective control method currently is the injecting of sodium bisulfate into the starfish which kills the organism in a matter of days. However, this method is costly and is not a permanent solution to the problem. The Cooperative Research Centre for the Great Barrier Reef World Heritage Area and the Australia Institute of Marine Science Research are conducting various research projects looking for environmentally sound and economically practical methods of controlling Acanthaster planci populations.
Acanthaster planci, commonly known as the crown-of-thorns starfish, is an echinoderm that has attracted much attention and has been the focus of much research over the past few decades. Although the starfish has interesting physical biology, this is not what has sparked the sudden interest. Instead, it is A. planci’s distribution and population dynamics that worry scientists. Population explosions, or outbreaks, of the starfish occurring over the past 30 to 35 years have caused concern because of A. planci predation of the coral. An outbreak of the starfish can devastate a reef. The scientific community has so far been unable to pinpoint a specific cause for these outbreaks. Some suggest that the population explosions are natural phenomena that have occurred for thousands of years. However, others believe that the outbreaks are a recent occurrence caused by human interference in the reefs, mainly human elimination of starfish predators. Currently, methods of starfish control, possible causes of outbreaks, and general starfish biology are being vigorously researched in hopes that a solution to the problem will come to light.
Acanthaster planci is an echinoderm of the class Asteroidea. An adult organism may grow anywhere from 25 to 35 cm in diameter with the largest recorded individual being 80 cm. The organism’s size is dependent on what it eats, availability of food, and the number of other starfish in the population. The...