Development of a major barramundi industry in Lake Argyle in the Kimberley region of WA is proceeding, with a developer obtaining approvals for a 600 tonne production licence and production rising rapidly as the fish approach market size. In the process of seeking these approvals, and also through a strategic environmental review of the opportunities for aquaculture in this area by Department of Fisheries (Report No. R700), the issue of environmental impacts by barramundi aquaculture has been considered a key-limiting factor to expansion towards a major 10,000 tonne industry in Lake Argyle. Presently, the capacity of the Lake Argyle ecosystem to sustainably maintain certain levels of barramundi cage culture is unknown and models need to be developed that will assist in determining the carrying capacity of specific areas of the lake. By comparison to other cage aquaculture scenarios in Australia, the one at Lake Argyle is largely unique, in that large-scale aquaculture in a tropical lake system is not being conducted elsewhere in Australia. However, a sound understanding of the environmental sensitivity of the Lake Argyle ecosystem is lacking. Clearly, for long-term management of this industry, an improved understanding of the level of hydrodynamic and environmental variability and key control points for environmental management of barramundi cage culture need to be defined. Similarly, critical control points of barramundi cage culture environmental discharge (both soluble and solids) also need to be more fully explored.
This project will build on from an existing project of the principal investigator’s, presently underway at Lake Argyle, auditing the nutrient discharge characteristics associated with barramundi fed existing commercial diets.
Final report
A preliminary sensory evaluation study was conducted to confirm the presence of a taint issue. Prior to this the issue was reliant on purchaser feedback and was not verified independently. To examine the issue of flavour taint a series of barramundi samples were collected from Lake Argyle (purged and unpurged), wild (estuarine) and marine-farmed barramundi were assessed. No significant differences in flavour attributes and/or acceptability attributes were detected between the wild and farmed barramundi, provided the barramundi was either marine-farmed or purged. However, it was determined that a clear “muddy” flavour and odour could be detected in the unpurged Lake Argyle fish, but not in any of the other samples. From this finding it was decided to establish an independent professional sensory panel to assess a range of key factors that may influence the sensory perception of the muddy taint issue. A number of other differences in flesh colour and texture were also observed.
The project also resulted in the establishment of a trained sensory panel at the Queensland Department of Primary Industries (QDPI) Centre for Food Technology (CFT) for the assessment of flavour-taint in barramundi. From this, cross-referencing to some untrained sensory work was also undertaken and showed that similar results could be achieved from untrained panels.
