Amoebic gill disease (AGD) research remains a high priority for the Tasmanian salmon industry. Within this framework there is a need to develop, both for research and practical reasons, non-destructive quantitative measures of AGD severity. This PhD project will develop a state of the art quantitative real time PCR (qRT-PCR) method for AGD-causing Neoparamoeba perurans. If successful this will be the first such DNA test of its type in the world for this disease. The assay will then be utilised to answer practical questions such as profiling host-parasite dynamics in vaccinated and non-vaccinated salmon prior to, during and after commercial freshwater bathing treatment, providing a rigorous measure of vaccine efficacy, and much-needed insights into the parasite loading exhibited by the different experimental salmon groups. The N. perurans DNA test will then be extended to selectively-bred salmon, correlating pathogen load with breeding values for resistance in F2 stock. This could provide a more reliable way of quantifying infection than current gill scoring methods, and will be the first time such a tool is applied to gain more precise information from a commercial salmon selective breeding program. Finally, the project will then apply the qRT-PCR test and other N. perurans molecular markers to the wider environment to address questions of population genetics, environmental reservoirs (providing much-needed information on the parasite life cycle, a prelude to in vitro culture which would benefit vaccine development), and parasite dynamics in heavily-farmed and virgin marine environments to address fundamental questions as the Tasmanian salmon industry contemplates a move towards off-shore aquaculture.
This project is a high priority for the Tasmanian salmon industry and was adopted into the CRC at its inception. This PhD project has the support of the industry. The project also has strong alignment with the industry run selective breeding program.