A survey of the benthic molluscs of the Dampier Archipelago, Western Australia

WA Museum Records and Supplements | Updated 7 years ago

ABSTRACT – A total of 695 molluscan species was recorded from intertidal and subtidal surveys conducted at the Dampier Archipelago, Western Australia during October 1998 and August-September 1999. There was a considerable degree of overlap in the molluscan faunas of the eastern and the central and western sectors. However, an east/west gradation in bottom type and exposure is associated with a significant difference in the faunas of the two areas. Of the 523 species recorded from the steeper, higher energy eastern sector, 153 were not recorded from the central and western sectors. Similarly, 180 of the 536 species from the generally more sheltered waters of the central and western sectors were not found further east. However, 199 species were recorded from only a single station during the two survey periods, with 92 of these being found only in the eastern sector and 107 found only in the central and western sectors. Such records contrast with those of the 29 species recorded from 20 or more stations. The greatest diversity of molluscan species was recorded from subtidal habitats characterised mainly or exclusively by living or non-living hard substrata. A slightly lower but comparable diversity was recorded from intertidal and subtidal soft substrata. The molluscan diversity of intertidal hard substrata was approximately one-third that occurring on subtidal hard substrata and on the combined intertidal/subtidal substrata. The diversity of the fauna of these three habitat groupings was much greater than that recorded from the mangals and those recorded in close association with plants and other animal groups. More detailed examination of these habitats than was possible during this survey would undoubtedly lead to an increase in these numbers. The overall diversity of molluscan species recorded for the Dampier Archipelago waters during this survey is greater than those of other Western Australian areas between the Houtman Abrolhos and the western Kimberley areas which have been similarly surveyed.