Crown-of-thorns starfish (Acanthaster planci L.), or COTS, is a predatory starfish that feeds on corals across the Indo-Pacific. If the COTS population density increases sufficiently for their feeding rate to exceed the average growth rate of the coral, this is referred to as an ‘outbreak’. These outbreaks are a major cause of coral mortality in the Indo-Pacific and, without management, have the potential to diminish live coral cover in a matter of years.
This study was a joint effort between the author and People and the Sea, which is a marine-based conservation initiative based on the island of Malapascua, Republic of the Philippines, that works to improve the biodiversity and overall health of the reefs. In January 2018, there was a COTS outbreak on the east coast of the island. From this point until March 2019, a manual control programme was in place, removing COTS from the affected site. The aim of this study was to determine if the coral reefs around the island would benefit from a new control programme to manage the population of COTS, while looking at the success of the previous removal effort, other sites which could be experiencing outbreak densities of COTS, and COTS feeding preferences.