The Blacklip rock oyster, S. echinata, is an emerging species of tropical oyster displaying several characteristics that suggest it would be well-suited to bioremediatory applications. These include a large size and fast growth rate and resilience to fluctuations in temperature and salinity. In order to investigate the bioremediatory potential of Blacklip rock oysters the present study aimed to: (i) determine the influence of temperature (20, 24, 28, 32 °C) on the filtration rate of S. echinata; (ii) describe and quantify the uptake in total nitrogen (TN), total phosphorus (TP), total suspended solids (TSS) and chlorophyll A, using prawn pond effluent and two levels of oyster stocking density.
The results demonstrated that higher water temperatures promote a faster filtration rate and identified an optimal performance range of 24 – 32 °C for a filtration rate of 12.68 – 15.20 L/hr/g. A maximum filtration rate of 15.20 L/hr/g was achieved at 24 °C (Fig. 1).
In addition, the high density (0.66 oysters / L) of stocked oysters resulted in significant reduction of all parameters, with TN reduced by 21%, TP reduced by 27%, TSS reduced by 99% and chlorophyll-A reduced by 39% when compared to the original effluent. Tissue analysis of 10 oysters with a mean whole weight of 75.4 g, revealed a mean of 0.09g of nitrogen per oyster. Scaling these values suggests that 1.20 kg of nitrogen is removed per tonne of harvested oysters. This study is the first to investigate the bioremediatory potential of S. echinata and demonstrates their potential to improve aquaculture wastewater treatment practices and bioremediation. The findings of these several studies have a direct application to this emerging industry and will hopefully assist in the future commercialisation of the species.