Shellfish reefs and soft sediment beds characterised by ecosystem-building bivalves are increasingly recognised as biodiversity hotspots and vital to seascape function. Nevertheless, the ecosystem functions of many bivalve species are poorly described, yet essential for informing management and restoration efforts. Razorfish clams (Pinna bicolor) are Southern Australia's largest bivalve and occur in soft sediments in both the intertidal and subtidal zones. While they are widespread throughout the Indo-Pacific region, their role in provisioning consolidated structural habitat has been poorly investigated.
In South Australia's gulf systems P. bicolor historically formed extensive shellfish beds, which have since declined due to overharvesting, pollution, and coastal modification. Subsequently, the aim of this research was to quantify the habitat value associated with differing densities of alive and dead P. bicolor shells from remnant shellfish beds situated in the Port River estuary, Gulf St. Vincent. Video observations and predation assays demonstrated the use of P. bicolor beds by several fisheries-targeted species. Microhabitat differences between sites were also associated with unique infaunal and epifaunal communities, particularly cryptic organisms. These results underscore the ecological significance of another type of intertidal shellfish ecosystem and the value of understudied ecosystem-building species such as P. bicolor.