The macromolluscs of Mermaid (Rowley Shoals), Scott and Seringapatam Reefs, Western Australia

WA Museum Records and Supplements | Updated 7 years ago

ABSTRACT – This paper records 339 macromolluscan species comprising 261 gastropods, 70 bivalves, six cephalopods and two chiton species from the north-western Australian atolls of Mermaid Reef (Rowley Shoals), Scott and Seringapatam Reefs.

These records result from a survey undertaken by the WA Museum in September 2006, during which both qualitative and quantitative data sets were recorded. The data included a comprehensive inventory of molluscs, based on a presence/absence statistical assessment, and quantitative density records along replicated transects at outer slope and lagoonal stations. The qualitative survey results are compared with those from WA Museum surveys to the Rowley Shoals in 1982 and Scott and Seringapatam reefs in 1984, as well as from other locations of regional significance. While Mermaid Reef appeared little affected, habitat changes were apparent on Scott and Seringapatam Reefs. The shifts in some molluscan populations since the surveys in the 1980s may be related to warm water incursions, cyclonic activity and/or unregulated fishing. The populations of three gastropod species, Cerithium echinatum, Conus miliaris and Conus musicus, appeared to have increased, probably due to habitat change, when compared to data from the 1980s. However, the populations of giant clams (Tridacna spp. and Hippopus hippopus) and trochus (Tectus niloticus) on Scott and Seringapatam reefs had significantly declined, probably with the added pressure of unregulated fishing. These latter declines are supported by the findings of the senior author during a separate survey concerning a survey of the invertebrate marine resources of Scott Reef, Seringapatam Reef and Browse Island in February, 2006 (Bryce, 2006). A new Australian record for Marchia martinetana (Röding,1798) (Muricidae), is documented from North Scott Reef, and three new Western Australian records, for Euplica deshayesii (Crosse,1859) (Columbellidae), Notodoris serenae Gosliner and Behrens, 1997 (Aegiridae) and Monitilora simplex (Reeve,1850) (Lucinidae) are also documented. The records of Pitar spoori Lamprell and Whitehead, 1990 (Veneridae) is also significant as that species has only previously been recorded from Hibernia Reef, off north-western Australia.