Echinoderms of the Dampier Archipelago, Western Australia

WA Museum Records and Supplements | Updated 7 years ago

ABSTRACT – The results of two diving surveys (DA1/98 and DA3/99) and a dredge survey (DA2/99) conducted in the waters of the Dampier Archipelago, Western Australia, are summarised. The diving surveys sampled 70 sites in the eastern (DA1/98) and western (DA3/99) halves of the Archipelago. Considerable differences were demonstrated between the echinoderm faunas of these areas, with more species (139) recorded in western than eastern (115) areas and only 74 species in common between the two. There are major habitat differences between the eastern and western parts of the archipelago, with more areas of soft substrate in the western part, providing more habitat for astropectinid starfishes and burrowing heart urchins. The dredging survey (DA2/99), which sampled 100 sites spread throughout the archipelago, showed that the area has an extremely rich echinoderm fauna, unmatched by any other in Western Australia. Fifty-two percent of the species taken by dredging were not found on the dive surveys. A complete list of all species found during the diving and dredging expeditions (260) and a supplementary list of material from the Dampier Archipelago held in the Western Australian Museum are presented, making a total of 286 species, the highest number recorded from any part of Western Australia. This rich fauna is a reflection of the diversity of habitats and the range of exposure to wave action, turbidity and currents related to the complex topography of the archipelago. The archipelago is the type locality of three valid echinoderm species and two from deeper water north of the archipelago. The distribution of species falls roughly into five groups: 9% are endemic to northwestern Western Australia, with some extending into the Northern Territory; 11% are endemic to northern Australia including Queensland and some extending to New South Wales; 28% extend northward to Indonesia, with some to Japan; 47% are widespread Indo-West Pacific species; and 6% are Indian Ocean species extending to the Red Sea or Persian Gulf.