Decadal status of Acanthaster planci (Linnaeus, 1758) along the coral reef habitat of Andaman and Nicobar Islands

Abstract

The coral reef habitats have been facing insightful threats from natural and anthropogenic sources across the world; while natural threats are creating major ecological pressure with the maximum percentage of devastation to the entire ecosystems. The Acanthaster planci (L) or Crown-of-Thorns Sea star (CoTS) is known as potential natural predator of corals and can disrupt the entire reef ecosystem with their outbreaks within the much-stipulated time.  CoTS are reported from all the reef areas of Andaman and Nicobar Islands with a mean density of 0.71/ hectare within the range of 1.08±0.33 to 0.40±0.18 per hectare between North & Middle Andaman and Nicobar, respectively. The distributional pattern of CoTS signifies that the reef crest represents maximum occurrence in comparison with reef slop and reef top; while an inversely proportional relationship can be seen between the occurrence of individuals and depth gradients. Maximum association of the CoTS is recorded with acroporidae corals while corallivorous impacts of CoTS are also recorded with poritidae corals which are not much reported across the world. No observation on the population outbreaks of CoTS was made during the decadal study period from Andaman and Nicobar Islands while the density is intrinsically noted within the limit of the natural population level of CoTS. The presence of natural predators like CoTS in Andaman and Nicobar Islands used to take a leading role in the balancing of reef ecology which denotes the healthy reef ecosystem of this archipelago.