For tuna ranching to continue to develop it must improve the farming environment by providing optimum water quality to the tuna. This will improve the performance of farming operations and deliver quality products to the market and ultimately maintain Australian farmed tuna’s competitive edge.

Also the next major step in the industry's sustainable expansion strategy is longer term holding (eg. 15 months). The above planned outcomes of the anti-foul project are important prerequisites to successful long-term grow out.

The need for this project is quite obvious. If the culture environment is improved by the use of this product, more than likely the following will occur:

• Increased water flow through the nets
• Reduction in weight on farming structures
• Reducing the re-suspension of sediments during rough weather
• Reducing surface area for potential pathogens
• Improving net handling techniques
• Potential to increase longevity of nets
• Reduce or eliminate the need for diving to clean equipment.
• Improve cage integrity.

This project aims to integrate and coordinate the industries approach on anti-foul treatments and ensure this meets with regulatory requirements. Furthermore, it is necessary to find out the efficacy of anti-foul treatments by monitoring key biological and farm husbandry parameters through trials on commercial farms. As mentioned previously, the research farm identified that the product tested showed promise and this combined with the industry panel work enabled the manufacturer to make the necessary alterations to formulations and make new products to improve performance in Spencer Gulf.

Economically it is important to find out how long a single treatment will provide a reduction of fouling organisms given the current operating format of the industry. The cost to treat a net is significant but if the objectives are achieved then the benefits outlined in section B3 under “Need” will outweigh the costs. This includes whether nets need to be treated every season, or whether one treatment will reduce fouling over two seasons.

There is a need to provide confidence that the active constituent found in the anti-foul treatments are not absorbed by the cultured organism (in this situation being tuna), is not found in the sediments and is not taken up by other marine organisms that are located nearby.

Finally, it is a clear objective to disseminate results to industry every step of the way by forming close links with industry. Further to this extension role, results will be published in the “Tuna Brief” which is a recognised printed or electronic short communication within the tuna industry for disseminating research results. In addition, results will be presented at open forum industry research meetings.

The Tasmanian fishing industry and management identified the need for a better understanding of structure and strategies of the scalefish fishery. This information ranges from the number of fishers targeting the various species, to the degree of operational specialisation or generalisation, and the seasonal and spatial fishing strategies including key drivers for fishing decisions.

Amalgamating these dynamics in multi-species and multi-gear fisheries into a holistic fishery approach in stock assessment and management, rather than the commonly-used single-species approaches, is needed. Such an approach is crucial to reduce unexpected cross-species impacts brought about by effort shifts between different components of the whole fishery as a response to changes in management measures and/or resource availability.

This proposal addresses three key research and development priorities for wild fisheries outlined in the Tasmanian Fisheries and Aquaculture Research Strategic Plan (2005-2008): 'Management options/assessment' by seeking to optimise management measures for the scalefish fisheries; 'Resource assessment & monitoring' by providing information on the current and projected structure of scalefish resources; and 'Impacts of fishing' by supporting the evaluation of the effects of alternative management and fishing scenarios on fished populations.

This project addresses also the FRDC R&D ‘Natural resource sustainability’ priority to ‘Measure and mitigate the interactions of fishing and non-fishing activities on the aquatic environment and fish stocks‘ and ‘Developing spatially explicit management models for fish stocks’. Considering the spatial overlap and interactions of scalefish species and their fisheries, the project supports the FRDC's strategic vision to move towards assessment and management of Australia’s fisheries at the ecosystem rather than single-species level.