Bioerosion of Porites corals in the central Great Barrier Reef

Sponge bioerosion was studied on three cross shelf transect reefs. 29 samples were used for the study, sourced from Myrmidon Reef, Rib Reef and Pandora Reef. Cross sections of Porites spp. were examined for bioerosion traces which were categorised by the appearance of the excavation patters by organisms (sponge, molluscs, worms and others). Occurrences of sponge bioerosion were further categorised according to architecture of the excavation pattern (porous, cavernous). An analysis of the surface area of samples was conducted by an image analysis of each sample for live and dead surface. Subsequent collection of data for percentage of area removed and dead area on the corals, enabled a comparison between reefs and the sum of bioerosion with contributing factors.