Pinctada albina is a tropical pearl oyster introduced into the upper Spencer Gulf in South Australia. Its recent establishment has raised concerns about potential impacts on marine communities through the loss or replacement of native habitats - the upper Spencer Gulf is largely a soft sediment system with limited naturally occurring hard substrate, so abundant P. albina shells may provide additional habitat. It remains unclear, however, whether P. albina introduces a novel habitat or supplements existing ones, and how this affects biodiversity. To assess this, we compared biodiversity associated with P. albina to that of local substrates, examining epifauna communities on shells and fish assemblages in dense beds of P. albina. Epifaunal assemblages on P. albina shells were compared with those on naturally occurring hard substrates in the intertidal zone (Pinna dolabrata shells and rocks), while fish assemblages in subtidal habitats were assessed using (unbaited) remote underwater videos (RUV) across P. albina, seagrass meadow, and sand. Analysis is ongoing, but assemblages associated with P. albina are broadly comparable to those on natural habitats, suggesting that P. albina supports functionally similar habitat; although large densities of pearl oysters may still influence biodiversity by increasing the total area of hard substrate available.