Serpulid worms associated with the protection of Porites coral from crown-of-thorns starfish (Acanthaster planci) predation on the Great Barrier Reef

A novel mutualistic relationship was observed between the serpulid worm, Spirobranchus giganteus and massive coral colonies of Porites lutea and Porites lobata as a response to Acanthaster planci predation on reefs of the central Great Barrier Reef.Field censuses were carried out at Potter Reef in April and June 1985. This reef, along with many others in the region, had supported large populations of Acanthaster planci (crown-of-thorns starfish) throughout 1983-84. Co-occurrence of the worm with these corals (a = S. giganteus and dead coral; b = no S. giganteus and dead coral; c = S. giganteus and live coral; d = no S. giganteus and live coral); the state of predation (Partial, Total); and the number of colonies (31) with/without worms was recorded.
To examine the correlation between the worm, S. giganteus and survival of coral polyps on Porites after predation by crown-of-thorns starfish.
In the study area, the only living polyps on Porites colonies following predation by Acanthaster planci commonly occurred in patches hosting populations of serpulids, or directly below the worms' extended branchial crowns (3 to 5 cm diameter) with evidence of regrowth more than 2 years after predation. Note that Porites polyps were not protected in all cases.