Attempts have been made to explain the sudden increases in Acanthaster populations since the mid-1950s and their impact on coral reefs. A. Larvae Acanthaster populations have preyed on coral reefs and caused the loss of coral cover over large areas and the collapse of some coral reef communities. B. Acanthaster outbreaks have been attributed to natural phenomena such as stroms that have created favorable conditions for the rapid development of the starfish larvae. C. Acanthaster ourbreaks are the results of natural processes that have led to some increases in the past, as well as of human impact that has sped up the frequency and severity of the outbreaks. D. There are several hypotheses trying to explain the Acanthaster outbreaks but none have elements of the truth because they contradict each other. E. The crown of thorns starfish, Acanthaster Tlanci, is large, twenty-five to thirty-five centimeters in diameter, and has seven to twenty-one arms that are covered in spines. F. The favorable anthropogenic causes, such as destruction of coral by blasting and other bad land use practices, have provided Acanthaster more food sources and therefore stimulate its population outbreaks.