A viable inland saline aquaculture industry will only develop if existing constraints to production are overcome and if the environmental impacts from effluent, which are an inevitable consequence of increasing production, are managed appropriately. The innovative SIFTS technology offers an order of magnitude improvement in fish production by its ability to grow high densities of fish at low cost, by efficiently preventing solid waste products from entering the natural environment, and by maintaining optimal oxygen levels and therefore fish growth even during algal blooms. Linking SIFTS to the irrigation of crop plants provides a cost-effective option for managing effluent and the potential for additional returns. These systems work in the laboratory, but it is essential that they be rigorously tested on a commercial scale in the field. The proving of the SIFTS technology in the small water bodies of the WA Wheatbelt will make the technology immediately available to other environments such as in freshwater lakes, storage reservoirs and in coastal areas where its superior production and waste minimization capabilities will be highly regarded both by industry and the community. For inland saline areas, the innovative SIFTS technology offers to transform the existing low-intensity, cottage industry into a commercial industry.
The need for this research is reflected in both FRDC’s National R&D plan for Inland Saline Aquaculture and the RIRDC R&D plan for Integrated Agri-Aquaculture Systems (IAAS). Specifically, the former R&D plan calls for the ‘identification of constraints to commercial developments and methods of overcoming these’, whereas the latter highlights the need for ‘appropriate, in-situ industry trials to evaluate suitable system design requirements from IAAS operations’.
Final report
We have demonstrated that yields of 10 tonnes of fish per hectare cannot be sustainably achieved in static, autotrophic saline (14 ppt) ponds (i.e. ponds dominated by photosynthetic organisms) over a 3-4 month production cycle, despite the removal of settable wastes from the SIFTS. The outcome of this finding was to advise potential industry entrants of this fact and to further investigate alternative options to enable such yields to be achieved.
Our work on integrating heterotrophic pond management techniques (i.e. ponds dominated by bacterial organisms which utilize organic carbon as an energy source) with carnivorous fish production in SIFTS have demonstrated that 15 tonnes per hectare are achievable over a 100 day production cycle. Economic analysis revealed that the profitability of a stand-alone enterprise growing carnivorous fish in SIFTS within heterotrophic ponds would be marginal at 150 tonnes per year of production. The outcomes of these trials have already been used to design further trials on optimizing heterotrophic pond management at the Queensland Department of Primary Industries’ Bribie Island Aquaculture Research Centre. Demonstrating that SIFTS can be integrated with heterotrophic pond management systems creates an opportunity for existing prawn farms using heterotrophic pond management to integrate barramundi farming into their existing operations with minimal changes required to their operations. The McRobert Aquaculture Group are discussing the integration of SIFTS into prawn farming ponds and settlement raceways with the prawn farming industry in Queensland.
The main outcome of our research using NyPa Forage to treat salinised and eutrophied waste is a further project funded by the RIRDC, in which NyPa Forage will be grown on a larger scale in the field and it’s nutritive value determined in livestock in vivo. As a result of our project, NyPa forage is being investigated to fix atmospheric carbon under a carbon credit scheme. The ‘Degree Celsius’ project is a collaboration between Terrain Natural Resource Management and BioCarbon, a private company, who are investigating the carbon storage capability of NyPa Forage in an effort to make valuable use of salt affected lands.
Keywords: Inland saline aquaculture, Semi Intensive Floating Tank System, SIFTS, barramundi, rainbow trout, heterotrophic pond management, halophytes, NyPa, Artemia
