Metazoan parasites threaten the sustainability and profitability of the Australian finfish aquaculture industry. It is critical, therefore, to identify local parasite species and determine which are potentially harmful. There have been many studies assessing metazoan parasite fauna of wild fish and fish farmed in sea-cages in the northern hemisphere, but such research is notably absent in the Australia. With current low stocking densities and dispersed farm locations in Australia, the potential for parasitic disease problems in sea-cage aquaculture may not yet be realised.

In the sea-cage environment farmed fish can acquire infections found in local populations of wild fish. The natural occurrence of wild fish near sea-cage farms provides an opportunity for transfer of parasites between wild and farmed populations. The parasite assemblage of the wild fish species and the potential risks of these parasites for sea-cage aquaculture are largely unknown. By gathering biological data about parasites, we will gain a better understanding of how to manage and control them on fish in captivity.

Parasite identification, knowledge of parasite biology, diagnostic tools and how parasites impact on their host is critical for effective parasite management. This project will use a powerful combination of morphological and molecular genetic techniques to provide a comprehensive understanding of copepod, monogenean and trematode parasites infecting selected aquaculture, recreational and commercial finfish species in southeastern Australia, plus barramundi in the northwest.

This research will enable proactive parasite management and rapid identification of pathogenic parasite species. It will also identify appropriate site selection for expansion of the industry away from infection sources. Appropriate husbandry practices and management practices can be put in place to control parasite infections thereby reducing morbidity and mortality in fish stocks.

The vast majority of the Southern Bluefin Tuna (SBT) farmed in South Australia is sold fresh for sashimi production in Japan. Premium prices are obtained for sashimi grade tuna with a high fat content. Unfortunately, fatty fish tissues with their high polyunsaturated fatty acid (PUFA) content are prone to oxidation. This results in poor flesh quality, reduced shelf life and significant trimming of the tuna carcass at the market.

FRDC Project No. 2004/209 investigated the impact of dietary supplements on the flesh quality of farmed SBT. Specifically, it investigated the impact of the dietary antioxidants vitamins C and E and the mineral selenium. Project No. 2004/209 showed that these supplements can extend the shelf life of muscle samples taken from farmed SBT fed diets containing higher than normal concentrations of the antioxidants.

Although Project No. 2004/209 has been very successful, performing diet trials with live SBT is expensive and logistically difficult. It is also time-consuming and the statistical power of the experiments is limited by the fact that it is economically unfeasible to have multiple replicate sea-cages for each dietary treatment. As a result of these constraints, experiments must be repeated over several years to obtain statistically valid results.

Recently, we produced the world’s first SBT cell line and to our knowledge the first cell line for any tuna species. The cell line has the potential to reduce the number of experiments with live SBT and to greatly increase the number of dietary supplements that can be screened in a given period of time. With the cell line, it takes only one week to screen 24 different supplements with 3-4 replicates of each. This compares with years for similar experiments with live SBT.

This project will evaluate the cell line as a platform for testing dietary antioxidant supplements for SBT.

With most of Australia's fish stocks at fully fished or overfished status, there is reduced opportunity for increasing economic returns from larger catches or unexploited resources. As a result, the fishing industry is looking for opportunities to increase its profit margins by reducing the cost of fishing. Generally, fuel is the one single highest operating cost to fishing vessels, accounting for up to 50% of the operating costs of a fishing vessel in Australia.

The Australian (and New Zealand) Fishing Industry requires assistance in becoming a more efficient user of energy. Some forms of fishing, such as trawling, expend more fuel per kg of fish landed compared to passive methods such as longlining and trap fishing. In all cases however, rising fuel prices impinge on the profitability of the operations, and ultimately put their viability in jeopardy; this has reach a critical situation for many operators in Australia.

The R&D plans and strategies of all advisory bodies to the FRDC contain high priority goals to achieve FRDC’s Industry Development goal (planned outcome):, The commercial sector of the Australian fishing industry is profitable, internationally competitive and socially resilient. This investigation into alternative fuels for the fishing industry, some of which also achieve lower greenhouse gas emissions, has the intention of improving the economic viability of fishing enterprises and shifting the industry towards a more secure position with respect to future fuel needs.