Seafood CRC: Extending biotoxin capability and research in Australia through development of an experimental biotoxin contamination facility to target industry relevant issues
Future oysters CRC-P: Species diversification to provide alternatives for commercial production
Future Oysters CRC-P: Advanced aquatic disease surveillance for known and undefined oyster pathogens
Oysters Australia IPA -workshop – identifying knowledge gaps for development of the native oyster aquaculture industry in South Australia
The establishment of a new native oyster aquaculture sector in SA will not only diversify the business risk of the existing Pacific oyster sector, but has the potential to become a multi-million dollar industry itself. As native oyster is an ideal alternative species to mitigate POMS, the successful development of this aquaculture sector will strengthen the confidence of existing/new growers and investors in both Pacific and native oysters; thereby encouraging further expansion of the industry. In addition, supporting species diversification is one of the high strategic priorities in the Oysters Australia Strategic Plan 2014-2019.
Final report
The 2015-229 “Oysters Australia IPA - workshop - identifying knowledge gaps for development of the native oyster aquaculture industry in South Australia” brought together oyster farmers, hatchery operators and scientists from across Australia to share their knowledge and experience with native oyster (Ostrea angasi) aquaculture and help to identify the key knowledge gaps in the production chain. Through presentations and group discussions, a number of research and development needs were identified. These were categorised into seven key areas: early life history/genetic improvement, farming, oyster health, post-harvest, marketing and branding, industry network and training and education. Across these categories, 19 key research and development needs were identified and prioritised via a post-workshop survey. The following four research and development needs were prioritised as being most important
- Having a constant and reliable spat supply.
Development of a selective breeding program to improve Bonamia resistance, growth rate, meat/shell ratio, colour, lustre, etc.
Establishment of good husbandry practices (e.g. handling, density, growing heights, sub-tidal vs. intertidal, seasonal effects, a system to suit O. angasi production).
Increase the shelf life/improve packaging/develop processing methods.
Identifying these needs will help to target future research to meet industry priorities and establish/develop the South Australian/Australian native oyster industry.
Keywords: Native oysters; Ostrea angasi; Australia; aquaculture
Oysters Australia IPA: the use of FRNA bacteriophages for rapid re-opening of growing areas after sewage spills
Oyster growing areas with reticulated sewage and/or waste water treatment plants (WWTP) in the catchment are all potentially affected by closures caused by sewage spills and overflows. Standard risk management practice following such events is to instigate a 21 day closure resulting in lost production, market share, reputational damage, and potential recall costs. The number of growing area closures related to sewage spills and overflows in Australia is significant. In NSW, harvest areas were closed on 100 occasions due to sewage spills between July 2009 and June 2014, resulting in 2688 days of lost sales. The use of FRNA phage as potential indicators of human enteric viruses could lead to a 50% reduction in the number of days closed.
In Tas, there have been 75 harvest area closures of greater than 21 days relating to sewage spills over the past 5 years, resulting in at least 1575 days of lost sales. One three week closure in the Pittwater growing area is estimated to cost approx. $250-$400k combined sales, depending on the season. The cumulative impact of these spills has been estimated to reduce the value of businesses by a combined value of $12 million. Not all sewage incidents result in human enteric viral contamination of shellfish. Factors such as the level of illness in the community, treatment level of waste, size of the spill, hydrodynamics of the growing area, and local growing area conditions all influence the whether a spill results in significant contamination of oysters. FRNA phages have not been used routinely as indicators in shellfish in Australia to date. If FRNA phage levels show contamination is negligible, regulators may allow re-opening of growing areas as early as 10 days after the spill following results from testing on day 7, significantly decreasing the cost of spills to growers. FRNA phages are also showing potential as general indicators of human pathogenic risk.
Report
Survey of Foodborne Viruses in Australian Oysters
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.