Where should I farm my oysters? Does natural Cadmium distribution restrict oyster farm site selection in the Northern Territory?
RD&E that addresses critical hurdles to Aboriginal capacity and enterprise development (e.g. quality assurance strategies) have been identified as priority areas of the NT RAC and the Indigenous Reference Group (IRG). NT Fisheries has been conducting research to support Aboriginal aspirations to establish tropical oyster farms in the Northern Territory (NT).
Heavy metals have been a longstanding concern as an impediment to the development of a tropical oyster industry. Cadmium (Cd) bioaccumulates in the tissue of oysters, and unlike E. coli or toxic algae, has a long depuration period. As a result Cd levels are a major determining factor on the saleability of farmed tropical oysters. McConchie, D.M & Lawrance, L.M (1991) and FRDC Project 2012-223 identified high Cd concentrations, which varied considerably across locations and water depth, in blacklip oysters (Saccostrea echinata) at location in Shark Bay, WA and South Goulburn Island, NT respectively. Following these projects naturally occurring heavy metals have been a presumed barrier to the establishment of an oyster industry in the NT, due predominantly to the exceedance of Cd trigger levels in the Food Standards Australia and New Zealand (FSANZ).
However, recent testing on market sized oysters farmed on long line trials at Pirlangimpi on Tiwi Islands have not shown high heavy metal concentrations and complied with the FSANZ. This suggests that Cd exceedance may not be an issue in all locations. We propose a multi-location survey of blacklip oyster (Saccostrea echinata) heavy metal concentrations across the NT to identify the best locations for commercialisation of this emerging aquaculture species. With the aim of identifying locations, like Pirlangimpi, that could produce oysters that comply with the Food Standards Australia and New Zealand (FSANZ). The results are needed to inform the development of a NT tropical oyster industry and the establishment of a NT shellfish quality assurance program.
Future oysters CRC-P: Species diversification to provide alternatives for commercial production
The establishment of a new native oyster and/or western rock oyster aquaculture sectors in SA and the former in Tasmania will not only diversify the business risk of the existing Pacific oyster sector, but has the potential to become a multi-million dollar industry itself. As native oysters would be more suited to subtidal or low intertidal culture while western rock oysters are an ideal alternative species to mitigate POMS, the successful development of these aquaculture sectors will strengthen the confidence of existing/new growers and investors in Pacific, western rock and native oysters; thereby encouraging further expansion of the industry. In addition, supporting species diversification is one of the high strategic priorities in the Oysters Australia Strategic Plan 2014-2019.