 Consistent with this, the Houtman Abrolhos contains a mix of tropical, temperate and west coast endemic fauna, resulting in unusual associations such as the occurrence of tropical corals in close association with temperate macro-algae.The proportions of tropical, temperate and west coast endemic biota vary from taxonomic group to group, but in general the biota is dominated by tropical species.This is attributable to the location of the Houtman Abrolhos at the northern limit of the Southwest Shelf Transition, together with the warming influence of the Leeuwin Current.