Investigation into opportunities for the use of inland saline groundwater for aquaculture in NSW started in the late 1990’s. A comprehensive inventory of NSW inland saline groundwater resources was completed, including ephemeral and permanent lakes, saline water from coal seam gas mining and sub-surface drainage schemes where saline groundwater was pumped to protect the root zone of crops. Research to identify suitable sites, species and production systems was followed by commercialisation plans and identification of investment opportunities.
NSW DPI and industry partner, Murray Irrigation Limited (MIL), constructed an aquaculture R&D facility on the bank of a 2000 ha evaporation basin within the Wakool Tullakool Sub-surface Drainage Scheme. The WTSSDS included 54 pumps initially producing ~35 ML/d of saline water keeping the groundwater 1m below the surface to protect the root zone.
Initially, the chemistry of the saline groundwater, which is different to coastal seawater, was measured and cost-effective methods of ameliorating deficiencies were developed allowing evaluation of species including marine fish (Australian snapper and mulloway), freshwater fish (rainbow trout and silver perch), marine prawns (black tiger and Japanese tiger) and Sydney rock oysters. Mulloway and rainbow trout were selected for long-term “commercial-scale” grow-out studies in ponds to provide data over annual production cycles and to highlight potential problems associated with grow-out in a semi-arid, inland environment. Market-size fish were sold into the local community to gauge market acceptance.
The culture of rainbow trout in raceways was identified as having the best opportunity for industry development. Commercialisation of this activity was started and consortium including an agribusiness R&D group (Lonsec), commercial trout farmers (Aquatic Solutions Australia), saline groundwater managers MIL and the Australian Seafood CRC. A business plan was developed and funding approved for a commercial demonstration farm at WTSSDS.
Advanced modelling showed that provided 20 ML/d of saline groundwater could be guaranteed, the farm could produce 200t trout/year and would be a showcase for inland saline trout farming, anticipating the technology would be transferred and adopted at other inland saline sites. Unfortunately, an ongoing drought through the mid-late 2000’s meant that irrigation of crops in the inland areas of NSW largely ceased. The saline groundwater table receded and precluded the need to pump groundwater into the WTSSDS. The volume of saline groundwater at the WTSSDS decreased from an average of ~ 35 ML/d in “normal” years to 4-5 ML/d in “drought” years. Water security could not be guaranteed by MIL and the project did not proceed.
A large collection of data, including inland saline groundwater resources, suitable species for inland saline aquaculture and economic analyses for development of commercial aquaculture using inland saline groundwater was produced by NSW DPI and is available for new enterprises looking to invest in inland saline aquaculture.