Australian barramundi (Lates calcarifer) farming industry presently enjoys freedom from numerous internationally significant diseases, including all of the Megalocytivirus genus of iridoviruses that are known to be causing severe impacts on finfish species globally. Australia currently allows the importation of uncooked, farmed and wild caught, non-salmonid finfish products for human consumption from several countries, as whole, and head-on eviscerated products. The importation of barramundi and other finfish products for human consumption had not been fully assessed as a risk pathway for disease incursion prior to this project. It was hypothesized that importation of uncooked, whole and head-on eviscerated non-salmonid finfish products may contain significant exotic viruses of concern, such as red sea bream iridovirus (RSIV), infectious spleen and kidney necrosis virus (ISKNV), scale drop disease virus (SDDV), Singapore grouper iridovirus (SGIV), or turbot reddish body iridovirus (TRBIV). These viruses are considered exotic to Australia and could present a significant biosecurity and disease threat, due to their highly contagious and pathogenic nature, if infection were to occur within an aquaculture or naïve wild fishery setting. It was also hypothesized that imported whole and head-on eviscerated uncooked non-salmonid finfish products may contain a substantial volume of high-risk processing wastes, which could make their way into waterways, therefore facilitating an incursion pathway for exotic diseases.
119 imported, uncooked, non-salmonid finfish products were sampled from seafood markets, seafood retailers and supermarkets across Australia, between June and October 2020. Tissues sub-sampled for diagnostic testing included gill, liver, and haematopoietic organs (spleen and kidney) on whole fish, and remnant tissue from above organs, from head-on eviscerated fish products. Samples were tested for SDDV, ISKNV (including the genotypes ISKNV, RSIV and TRBIV) and SGIV using qPCR. Confirmatory re-testing was performed on any samples that tested positive or inconclusive using the original nucleic acid extract and an additional nucleic acid sample prepared from the tissue homogenate by Australian Centre for Disease Preparedness (ACDP) Fish Diseases Laboratory. Sampled finfish products were assessed in relation to their compliance to import conditions. Results will be presented along with recommendations that were provided to help bolster Australia’s aquaculture industry from exotic disease risks.
The project was funded by the Australian Barramundi Farming Association (ABFA) and Fisheries Research and Development Corporation (FRDC).