Practical, feasible and low cost genetic selection of P. monodon for increased profitability
Aquaculture Nutrition Subprogram: evaluation of value-added grain protein products for Atlantic salmon and black tiger prawns
Treating prawns with an extended dip in Everfresh
Even when using a 4-hexylresorcinol dip the protection provided is not uniform (Guandalini et al., 1998). The residue from a once off dip drops rapidly over a number of days storage. The authors found that towards the end of organoleptic acceptability 20-30% of prawns were unaffected by blackspot. This researcher noted similar uneven blackspot development during storage (Slattery et al., 1995). This outcome is obviously due to uneven exposure and retention of the limited amount of 4-hexylresorcinol that a quick dip in a solution of the chemical can supply.
There is limited information on the effect of longer term treatment with 4-hexylresorcinol but only at the same concentration as the short dip (Iyengar et al., 1991 and Slattery et al., 1995). Providing industry with this type of information will lead to more adoption of a safer chemical and less chemical treatment of prawns.
Unlike Australia, many importing countries have defined residue limits which the product has to comply with. It is unknown what residues are likely from any long term exposure. The only information available is from a one hour dip of live prawns in the standard concentration which resulted in very high residues.
A range of methods of using Everfresh that will provide good protection from blackspot, yet result in low residues, is needed by the prawn industry. This research will assist the APFA Tactical R&D Plan by increasing profitability through reduced usage and wastage of expensive chemicals. The QSMA have been trying to convince the wild capture prawn industry to adopt the use of Everfresh for some time. This work would meet ASIC concerns for quality and safety of seafood. This project also complies with the SSA Plans for Seafood Quality and Safety in Segment 3.
Final report
Seafood CRC: Development of a quality index for Australian seafood
APFA integrated HACCP/QA/EMS program
Understanding and removing the barriers to Penaeus monodon domestication
Domestication of P. monodon is needed to address a number of vital issues for the Australian prawn farming industry:
1.The erratic supply of wild broodstock means that the quantity, quality and timing of supply of postlarvae to farms are all high risk and impairs the productivity and profitability of the industry.
2.The continued use of wild broodstock makes it extremely difficult to control introduction of disease as almost all wild broodstock captured on the east coast of Australia carry viral infections, most notably with gill associated virus (GAV), spawner-isolated mortality virus (SMV), and the gut and nerve syndrome virus (GNSV). There is a critical need to understand the disease status of founder stocks for domestication programs. This includes the development and application of rapid and accurate diagnostic tools as well as knowledge of how disease can be managed to permit increased productivity from domesticated stocks.
3.Selective breeding programs to increase farm productivity will not be possible until the life cycle is reliably closed on a commercial scale, and captive reared broodstock of high fecundity are routinely produced.
4.New methods of production that can minimise impacts on the environment, most notably full water recirculation systems, will not work well unless domesticated stock of known health status can be used.
Both the current viability of the Australian industry, and its future development, require domestication of P. monodon. Some industry operators have already switched production from their preferred species (P. monodon) to lower value species due to problems 1 and 2 above. Future enhancements in production systems (e.g. points 3 and 4 above) are critically dependent on the use of domesticated stocks.
The prawn farmers and their representative body the Australian Prawn Farmers Association (APFA) have developed a structured R & D plan. Research priorities were determined by the APFA Executive and by a separate poll of individual farmers. The R & D plan identifies the highest research priority is to overcome the barriers to
P. monodon domestication.