Where should I farm my oysters? Does natural Cadmium distribution restrict oyster farm site selection in the Northern Territory?
Department of Primary Industry and Resources (NT)
Communities, Environment, Industry
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.
1. Map the distribution and concentration of Cadmium in wild blacklip oysters across the Northern Territory.
2. Aboriginal communities better understand the role of shellfish quality assurance programs and the implications of Cadmium on oyster farming.
3. Risks associated with Cadmium are better understood and inform the development of a NT Shellfish Quality Assurance Program.
4. Knowledge is shared and retained through Aboriginal participation in the research project.