Cliona orientalis

Cliona orientalis is a demosponge found in the tropical Indo-Pacific region, from East Africa and Madagascar to northern Australia and the Philippines. This bioeroding sponge is known for its ability to live on and within calcareous substrates such as corals and molluscs. Its presence is often noted by the tunnels it creates in coral structures, a result of its unique method of bioerosion using chemicals produced by specialized cells. This sponge is a filter feeder, drawing water through its pores to extract nutritious particles, and it can also absorb dissolved sugars from the water. Cliona orientalis is a hermaphrodite, releasing sperm into the water column to be taken in by other individuals for internal fertilization. The embryos develop into free-swimming parenchymella larvae, which eventually settle on a suitable substrate to grow into juvenile sponges. While the species has not been evaluated for conservation status, it is considered harmless to humans. However, it plays a significant ecological role in its habitat by contributing to the breakdown and recycling of calcium carbonate structures. Divers observing this sponge may notice its distinctive bioeroding activity on coral reefs, where it interacts with various coral species.