FOULING SPONGES (PORIFERA) ON NAVIGATION BUOYS FROM SINGAPORE WATERS

A total of 62 sponge species was identified from subtidal (0-2 m depth) marine fouling communities present on 30 navigation buoys in the Singapore and Johor Straits examined between 2003 and 2006. Of these sponges, eight were new records for Singapore. Systematic descriptions are given for the six most prevalent fouling sponge species, which occurred on at least nine buoys of a total of 30 buoys examined. These are: Suberites diversicolor, Tethya robusta, Mycale (Carmia) sp. "red, encrusting". Mycale (Zygomycale) parishi, Amorphinopsis excavans and Cladocroce sp. "massively encrusting". The number of sponges on any single buoy ranged between two and 23 species with between four and nine species seen on the majority of buoys examined. A large proportion (67%) of the fouling sponge species were rare, occurring on fewer than three buoys during the three-year study period. This is possibly due to the small Surface area of the buoys. In the present study, only 19% (12 species) of specimens were identified to species level. A further 16% were tentatively assigned to known species, but these require comparison with type material for confirmation. The remaining 65% were assigned to genera and treated as operational taxonomic units (OTUs). An inventory of all fouling sponge species associated with navigation buoys in Singapore is also provided.