Acanthaster planci
(Linnaeus, 1758)
Enter the name for this tabbed section: Description
This species is easy to identify. It is large, often > 40 cm in diameter, and with numerous and large spines on the whole aboral surface. Color varies but does not correspond to different species; in Oman, blue and black morphs are most common followed by an orange and grey morph. Red or black A. planci are unusual. A recent genetic study identified 3 species of Acanthaster, whereas morphologically, there seem to be only one. In Oman, there are apparently two indistinguishable " genetic" species".
The specimens observed near Salalah seem to have a different coloration schemes with a less apparent radial color pattern and perhaps shorter arms.
The specimens observed near Salalah seem to have a different coloration schemes with a less apparent radial color pattern and perhaps shorter arms.
Enter the name for this tabbed section: Distribution
A. planci is found nearly everywhere in Oman where corals are found. Their abundance though fluctuates widely from region to region and also through time.
There was a large outbreak in the early 2000s. Starfish nearly disappeared in the late 2008-2009 but are now back in large number on many reefs near Muscat (2016).
There was a large outbreak in the early 2000s. Starfish nearly disappeared in the late 2008-2009 but are now back in large number on many reefs near Muscat (2016).
Enter the name for this tabbed section: Ecology and Biology
Like many starfishes, A. planci is carnivorous, but, unlke these other species, its diet is limited to corals and soft corals. When abundant, A. planci can destroy whole coral communities in a few weeks. In low abundance, their feeding create "holes" in the community in which new colonies of coral can establish themselves. This low level of predation contributes to increase the diversity of coral communities. Although the crown of thorn starfish is nocturnal, feeding scars, white dead coral patches about 50 cm in diameter, are often seen.
The spines of A. planci are venomous. The venom is distributed in numerous glands in the teguments that cover the spines.
The spines of A. planci are venomous. The venom is distributed in numerous glands in the teguments that cover the spines.