Research to provide data to support application for a minor use permits for chemicals including trichlorfon, chlorine, copper sulfate, hydrogen peroxide, benzylkonium chloride for control of disease including White Spot Syndrome Virus (WSSV) in Australian prawn farms.
Water disinfection for influent water biosecurity on prawn grow-out farms
• Coping with the potential persistence of WSSV in Australian waters
It is important for farms in the WSD risk region, as well as those outside it, to have access to the necessary tools and reliable information that enables them to implement highly effective biosecurity measures when they become necessary.
• Industry white spot disease preparedness
Chemical treatment to remove residual vectors and/or destroy the pathogen is currently the only practical approach with potential to adequately reduce WSD biosecurity risk associated with influent farm water. When assessment indicates a high disease risk, farms will need to be confident that their biosecurity measures will be immediately effective.
• Appropriate guidelines for using trichlorfon
Currently there is no locally generated guideline for achieving effective application of trichlorfon that is based on directly applicable experimental data and prawn farm experience. The industry needs a set of guidelines that expand upon the basic APVMA use conditions and define the environmental factors and application parameters that will provide the greatest protection for Australian farm conditions.
• Gaps in information currently available
The available information does not provide substantiated details of trichlorfon treatment methods and outcomes. The Australian industry needs validated treatment methods and their effectiveness and biosecurity outcomes verified.
• Constraints on trichlorfon use during production
Using trichlorfon to treat top-up and exchange water during the production cycle is problematic for some farms due to the 12 day conditioning period required to ensure toxic residues are below the detectable limit before stock is exposed to the water. The potential to manipulate water quality parameters to accelerate residue degradation could make treatment throughout the cycle a more practical option.
• Continuation of permit to use trichlorfon
Documented evidence of outcomes and impacts of trichlorfon use on farms is needed to support an APVMA application to extend its use beyond the current MUP period ending 31 December 2021.
Biosecurity operational planning for prawn farms in the Clarence River under increased risk scenario
Water treatment to control influent water biosecurity risk on Australian prawn farms. Effectiveness and impacts on production ponds.
Clarence Riven Green Prawn Market Diversification Assistance Measures
The Clarence River Region is known for its high-quality prawn markets. The region was kept profitable during COVID restrictions due to a significant portion of the fisher directing its product to the highly profitable bait market. This diversification away from the consumer market has ensured stability for the region. Many fishing businesses pivoted their strategies to meet this new buyer to the region. The loss of the uncooked prawn market in the Clarence region will therefore destabilize the industry.
The restriction of uncooked prawn trade therefore must be addressed through market research, diversification and activation.
However, there is immediate need for alternative markets so an intense focused market activation and access is the key.
PFA has identified key market persons that can create links between industry and high-end chefs to:
1. Identify alternative market uses that fall within the quarantine requirements
2. Start immediate market trials and activation
3. Review online presence and build industry skills to improve online presence for sales
• It is intended that this will lead into immediate supply agreements to these alternative markets that will in turn remove burden on the existing cooked prawn market
Australian Prawn Farms - Emerging disease investigation
Bacterial cultures from sick PL's from crashing hatchery tanks did not reveal a common pathogen across the multiple dying hatchery tanks.
Understanding the cause of the substantial hatchery PL mortality could be of value to all hatcheries across the prawn farming industry. Intermittent tank crashes are reported at most hatcheries over their history of operation.
With use of new diagnostic tools, such as next Generation sequencing, exploration for novel pathogens can be commenced using stored material from the hatchery outbreaks.
The further investigation of the hatchery and pond mortalities, offers the opportunity to better define the factors associated with the syndrome, thereby informing management measures for future seasons at this farm, and for the rest of the prawn farming industry.