Norovirus (NoV) is the leading cause of gastroenteritis outbreaks worldwide, and is commonly associated with shellfish. Between 2001-2010 seventeen Australian cases of suspected shellfish related NoV outbreaks were reported in OzFoodNet (Knope, 2011). More recently (March 2013) 400 people were reportedly affected by NoV following consumption of contaminated oysters from Tasmania.
Virus contamination in food poses major concerns for consumers and can impact export trade. The WHO/FAO working group (2008) on food-borne viruses, and European Food Safety Authority’s (EFSA) opinion (2011) ranked bivalves among the highest risk food groups in terms of NoV and hepatitis A virus (HAV). In 2011 the Codex Committee on Food Hygiene ratified a draft guideline on viruses in foods, with a specific annex on bivalves. It recommends that countries monitor for NoV and HAV in bivalves following high risk pollution events. Additionally, in early 2012 EFSA recommended the introduction of an acceptable NoV limit in oysters and the EU Community Reference Laboratory (2012) recommended an ‘absence’ criterion be applied for HAV in bivalves. Because of these impending international regulations (noting that some importing nations already require NoV testing), the Australian oyster industry members have indicated that they would like a more comprehensive evaluation of the prevalence of viruses in Australian oysters. There is little information on the baseline levels of NoV in Australian oysters. Although, a small pilot survey in oysters was conducted in production areas, more information is needed.
Recent developments made at SARDI in the use of molecular biology techniques for virus detection in foods would enable the occurrence of these viruses in bivalves to be determined through a virus prevalence survey. Similar surveys have been undertaken worldwide, including in the USA, UK, France and China, and might contribute to the development of market access strategies at the international level.

MDCA needs support to assist agencies such as FRDC to deliver key messages to the wider community and industry partners. Other organisations such as OceanWatch Australia, SeaNet, RedMap and a number of universities will also benefit. MDCA is seeking funding to enable 2 representatives from each Centre to cover costs associated with an annual network meeting. Each Centre hosts the annual event at their Centre, in a diverse range of marine bioregions around Australia.

Julie Haldane from FRDC has attended a number of network meetings and Peter Horvat attended the meeting in Queenscliff in 2009.

This application also addresses the following priority questions in the National Climate Change Adaptation Research Plan: Marine Biodiversity and Resources:

1. Aquaculture: many Centres are located in areas supporting aquaculture industries. We are a link with these industries direct to FRDC and provide information to assist them to adapt to climate change impacts.
2. Commercial and Recreational Fishing: Some Centres work closely with industry representatives in community based research projects. The Centres are a central contact point for industry and community members to access data and research results that may address key issues for their specific adaptation needs.
3. Conservation Management: Marine Discovery Centres are well-placed to deliver up-to-date educational material about the changes occuring in the marine and coastal environment.
4. Tourism and recreational needs: As above, MDCs are considered by the tourism industry as a link to important information about the impacts of climate change, both on capital assets as well as the environments in which they operate. All MDCs are located in key coastal regions and are a respected source of key information.
5. Cross-cutting issues: MDCs are central points that link research institutions, Govt agencies, industry and local communities to deliver important adaptation messages.

"Over-catch" (fouling) and pest species (oysters, barnacles, sea squirts, flatworms, mudworm) cost the Australian oyster industry an inestimable sum each year in grading and handling labour, product loss and reduced price due to unmarketable product. The pests are regionally specific, the issue is common across all growing areas and in all cases is a major financial burden. In NSW overcatch is currently treated through labour expensive heat treatment and stock management. The cost effectiveness of the alternate proposed treatment froms part of this proposal.

For example, oyster overcatch is one of the primary deterrents to interstate investment into Port Stephens, NSW which previously was a highly productive single species estuary. It is estimated that NSW production would be increased by 12.5% (GVP of almost $5m) through Marine Culture's use of a successful overcatch treatment in Port Stephens alone. Marine Culture propose to farm an output of 750,000 dozen Pacific Oysters off the area.

This project expands investigative research by NSW I&I (Heasman 2005) in which experimental, small scale cold shock trails “resulted in the death of advanced rock oyster over-catch in as little 5 seconds and complete mortality after exposure periods of 60 seconds and above. By contrast, no deaths nor discernable negative effects on the health and flesh condition of host Pacific oysters were detected for cold shock durations of up to 2 minutes”.

The project will include a more comprehensive range of oysters sizes and types, and fouling organisms. Further, and critically, the method needs to be assessed on a large scale under commercial operating environments to demonstrate practicality and cost effectiveness.

The oyster industries now require breeding programs to focus on quality and market appeal, to increase competitiveness alongside imported and alternative products.

This project will look for preliminary evidence of sensory variation between standard and selectively bred oysters sufficient to warrant further investigation. At least, it is necessary to ensure that selection within the oyster breeding programs does not diminish marketability characteristics.

Spawning and associated reduction in marketability is often at variance with demand for table oysters , and the possibility of selecting for lines with slower/faster maturation or which have an extended reproductive peak would provide growers with better control.

There have been suggestions that selected broodstock are more difficult to condition. This must be investigated to avoid what could become a serious future limitation of the breeding programs.

The Economic Weights Model developed in FRDC 2006/227 identified the time required to reach suitable shell size and the time required to reach a suitable market condition as traits under different genetic control. The model needs refinement by determining the relationship between the two traits. In order to accurately put economic weights on growth time and condition time it is important to measure this relationship for both Pacific and SRO.

Near Infra-red Spectroscopy (NIRS) offers the ability to perform a wide range of otherwise expensive biochemical measures of condition rapidly and cost efficiently.

Mortality is a serious, ongoing problem for Pacific oysters, particularly in SA and not confined to ASI stock. While the syndrome is undefined, there is evidence that susceptibility differs between ASI lines and that the difference is partly genetic (Ryan – unpublished; Pierre Boudry).

This project seeks to develop selection methods to enhance reproductive conditioning, marketability and survival and to develop oyster families which increasingly display these features.