A major problem for the culture of marine fish and crustaceans is rearing the early life stages of numerous species.. Live food is considered obligatory for success but is expensive (up to A$400-500 / kg). In recent years global harvests of Artemia cysts, particularly from Great Sale Lake USA, have decreased sharply leading to a worldwide shortage, especially for good quality cysts in terms of hatchability and nutritional content. Compounding the problem of poor supply are new AQIS regulations and biosecurity issues, which may limit future importation. The reliance of Australian hatcheries on imported Artemia is a major constraint to the sustainable development and expansion of this industry. Low cyst quality caused Artemia - related diseases throughout the world. In Australia, an additional concern is the risk of importing unknown, non-endemic pathogens into finfish and prawn hatcheries.

The need to find solutions is even greater now than 3 years ago due to the rapid development of the marine fish industry in Australia e.g. yellowtail kingfish from almost zero production to 2000 mt, and barramundi with predicted production of 4000 mt in 2003-04.

Hut Lagoon (Port Gregory, WA) where Cognis Pty Ltd is currently growing and harvesting microalgae (Dunaliella salina) for beta-carotene (supplying around 80% of global natural beta-carotene), is unique in the world in its capacity to grow high quality algae and Artemia, and for its pristine environment. The company is offering to invest significantly and estimated that the Hut Lagoon have the capacity to supply ALL the Australian needs in terms of both Artemia cysts (currently, around 5-7 mt dry cysts) and live adult Artemia and become a major export commodity capturing part of the world demand for cysts (much more than current production of 7 000 tons p.a.). An estimate of potential annual revenue for cyst production from Hut Lagoon is in the order of $ millions. Moreover, initial results shows that the waste from the algae extraction process can be used as food source for the Artemia, saving the company hundred of thousands of dollars in waste disposal fees. There is a need to properly and independently evaluate the commercial viability of Artemia production at Cognis.

Microdiets can reduce the need for live feed (and therefore costs, labour, diseases, risks) consumption in finfish hatcheries. However, with fish the poor development of digestive enzyme output is a major limitation. The prototype microdiet, developed in the current project, proved to be better than the best commercial available diet. Fish larvae microdiet prices, range between $150 and $250/kg. Commercializing the prototype microdiet together with an international feed company such as Skretting Australia (part of Nutreco – the biggest fish feed manufacture in the world) should bring in significant IP and ease pressure on Artemia supplies.

This project has arisen because of the Hepatitis A outbreak possibly associated with oysters at Wallis Lakes, 1997. Food safety issues are regarded by sea food industry as a major threat. While the majority of industry can see the benefit of implementing food safety plans others are still to be convinced. The hepatitis outbreak offers a unique opportunity to determine the cost both socially and economically of a major disease outbreak, its impact on consumers, and the economic benefit of effective food safety plans. The need for the project is:

1. to quantify the economic cost to the industry as a result of reduced market acceptance for oysters products;
2. to determine the extent that the outbreak impacted on other seafood products both from Wallis lakes and other sources;
3. the development of this economic analysis will allow the industry to assess the risk associated with addressing food safety issues;
4. to provide the basis for ABARE’s presentation to Outlook 98, which can be further extended to industry as a case study; and,
5. additionally, the project will act as a vehicle as part of FRDC's sponsorship of the fisheries outlook session of the 98 Outlook conference .

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The ability to isolate viruses in cell culture is fundamental to disease diagnosis in both human and veterinary (including aquatic animals) medicine. The In addition, the ability to grow the virus in culture provides a potentially limitless source of pure virus and thus facilitates further characterisation of the virus and development of more sophisticated and improved diagnostic procedures. At present, virus isolation in cell culture remains, for most pathogenic viruses where cell culture systems have been developed, the most sensitive and reliable technique for the detection of viral pathogens of fish (OIE, 1995a).

The current lack of continuous prawn cell lines suitable for the isolation and growth of prawn viruses is a major set-back for the diagnosis of viral diseases of prawns (see Crane and Bernoth, 1996, for review); isolation and identification of the causative agents is severely hindered and the development of other diagnostic procedures is slowed.

The application of virus isolation in cell culture and the critical role it plays in certifying freedom of disease and controlling the spread of disease is exemplified by its use in the international trade of salmonid products (OIE, 1995a, b). Individual salmonid cell lines are susceptible to infection by a range of salmonid viruses and provide an essential tool for health surveillance and certification programs and is a requirement for the international trade of specific products. Similar regulations may, in the future, be required for international trade of penaeid products.

The aim of this project is to develop continuous prawn cell lines which are susceptible to infection by a range of prawn viruses, to develop diagnostic procedures using these cell lines and to demonstrate the application of these cell lines to the development of other diagnostic procedures for viral diseases (both exotic and enzootic) of prawns.

References

Crane, M. St. J. and Bernoth, E.-M. 1996. Molecular biology and fish disease diagnosis: Current status and future trends. In: Recent Advances in Microbiology (V. Asche, ed.), Aus. Soc. Microbiol. Vol. 4, pp. 41-82.

O.I.E. 1995a. International Aquatic Animal Health Code: Fish, Molluscs and Crustaceans. First edition. 184 pp. Paris, Office International des Epizooties.

O.I.E. 1995b. Diagnostic Manual for Aquatic Animal Diseases. First edition. 195 pp. Paris, Office International des Epizooties.