This project will have significant impact on the industry as it will identify avenues for substantially improving farm profits by producing all-female populations. Production data from the Australian industry indicates sexual differentiation and maturation of Penaeus monodon (Giant Tiger Prawn) under commercial culture conditions occurs by 5 months of age, by which age females are on average ~30g and males are ~25g. This species is often harvested at even later ages by which time the size difference between females and males is even greater. As this project is focussed on improving pond yields it falls within the R&D priorities of the industry as outlined by the APFA
Relevant CRC Output(s) and Milestone(s):
Output 1.3 Removal or reduction of key production constraints in selected aquaculture systems
Milestone 1.3.1 New genetic tools and breeding strategies for genetic management and improvement of
at least two aquaculture species
(also refer to consultation and background)
Final report
Domestication and selective breeding programs in a number of cultured penaeid shrimp species worldwide have substantially improved commercially desirable traits compared to wild stocks. Improvements in growth rates, feed conversion efficiency, disease resistance and survival have been achieved in the important aquaculture species including Litopenaeus vannamei, Penaeus monodon, Fenneropenaeus chinensis and Marsupenaeus japonicus. However, there are substantial economic investments associated with the development of genetically superior lines in breeding programs and the intellectual property associated with such lines requires protection in the absence of effective legal mechanisms. Various technical strategies have been developed to protect these genetic resources with limited success to date.
Currently, triploidy is the only method known to guarantee inhibition of reproduction in shrimp and thus confer genetic protection. In addition, triploidy can increase the proportion of females in some shrimp species which is commercially desirable, as females grow faster than males. Triploid F. chinensis, M. japonicus and P. monodon have been produced by inhibition of polar body I or II formation during meiosis. A number of treatment agents to induce triploidy in shrimp have been trialled, with greatest success achieved using chemical and thermal shocks. However, current triploid induction methods cannot produce triploids at high or absolute rates and are not practical for commercial adoption due to the challenges associated with treating entire spawnings and the high mortality associated with the necessary handling of fragile eggs and embryos.
