 The sponges of the Houtman Abrolhos are poorly studied, although 109 species of demosponge have been collected there.In the most recent survey, 77 species were collected, of which around half are probably new to science.Only two locations were surveyed in this study, however, so this figure is likely to represent only a small proportion of the total sponge fauna of the Houtman Abrolhos; the islands are therefore thought to harbour an extremely rich diversity of sponges.