Feeding behaviour of the felt-, sponge-, and coral-feeder sea stars, mainlyCulcita schmideliana

Abstract

1. On the coral reefs of the Tuléar region (S. W. Madagascar), the feeding behaviour of sea stars, in particular the speciesCulcita schmideliana has been studied. It feeds in its usual biotope, the sea-grass beds of the inner reef flats, on the epibenthic film of the substrates, of the leaves, but also commonly on sponges, mainly the symbioticGellius cymiformis (associated withCeratodictyon spongiosum); 2. In the moat (residual pools, coral-built formations) of the inner reef flat where the population was poor in 1965 but equal to that of the sea-grass bed in 1972, the cushion sea star feeds on the epibenthic felt, but also on the living corals (Galaxea, Goniopora) and on soft corals(Xenia). This latter diet is very close to that of the Pacific cogeneric species,Culcita novaeguinae. 3.Acanthaster planci populations are normal on the reef flats of the region (but a little more dense on the fringing reef under silty deposits). Only a beginning of an infestation was observed in May 1972, but it disappeared later (condition 6 of Chesher's classification). 4. Others Oreasterids feed mainly on epibenthic film, extruding their stomachs on the substrates.Protoreaster nodosus has a larger distribution thanP. lincki, Pentaceraster mammillatus andChoriaster granulosus. 5. Among others sea stars,Asterina burtoni seems to be a large predator of species living under dead coral blocks (sponges, ascidiacea) of the boulder tracts and of the rubbly flats.