Whip coral distribution along a water-movement gradient

A dense meadow composed of two species of whip black corals, Stichopathes sp. and Cirrhipathes sp., was quantitatively studied in a site of the Bunaken Marine Park (North Sulawesi, Indonesia) characterized by high levels of water movement. In this area, the whip coral assemblage shows an average abundance of about 0.5 colonies m-2, among the highest recorded at world level. Along the studied cliff, the water movement intensity increases from the surface to the bottom. The abundance of Cirrhipathes sp. was found related to the current intensity while that of Stichopathes sp. remained unvaried along the cliff. This specific difference is probably due to the different polyps arrangement along the stem of the colony allowing Cirrhipathes sp. to increase food capture in more turbulent conditions of water movement