Biodiversity value of a geographically restricted soft coral species within a temperate estuary

1. A threatened and uncommon soft coral species, Dendronephthya australis found in large abundance in Port Stephens, within the Port Stephens-Great Lakes Marine Park (PSGLMP), New South Wales, Australia, was hypothesized to be an important habitat for many marine fishes and invertebrates, but is currently under threat from boat anchors, fishing debris entanglement and sand inundation. 2. Surveys were undertaken to assess the biodiversity associated with the soft coral habitat and its adjacent habitats (sponge, seagrass and unvegetated sand), using a combination of Underwater Visual Census (UVC) and Baited Remote Underwater Video System (BRUVS) techniques. 3. In total, 77 fish species and 21 invertebrate species utilized the D. australis habitat, and multivariate fish assemblages associated with soft corals were significantly different to those associated with nearby sponges, seagrass and sand habitats. Species richness of fishes and invertebrates were significantly higher in soft coral and sponge habitats than seagrass. 4. The D. australis habitat was found to be of high importance to juvenile snapper (Pagrus auratus: Sparidae), a species of recreational and commercial fishery importance, which occurred in highest abundance within D. australis, and were significantly smaller in size within the soft coral habitat than the adjacent sponge habitat. 5. Evidently, this rare soft coral habitat supports an extensive marine assemblage, potentially providing a valuable source of food and shelter for fishes and invertebrates, and given it is threatened by human-induced impacts, its protection should be a priority. Copyright (c) 2013 John Wiley & Sons, Ltd.