In April 1979, 323 species of fish were recorded from the South Passage area of Shark Bay. The majority of these are tropical species (83%), with smaller numbers of warm temperate (11%) and cool temperate (6%) species. Many of the tropical species, however, were found to be present in only low numbers, while some warm temperate and one cool temperate species were abundant. The fishes of South Passage, therefore, are considered to belong to an impoverished tropical fauna. Furthermore, South Passage is the southernmost mainland area of Western Australia which supports a predominantly tropical fish fauna. Its fauna is even more diverse than that of the Houtman Abrolhos, a very much larger area of offshore islands and coral reefs located to the south off Geraldton.