Dr Kathryn Wiltshire1, Dr Daniele Giblot-Ducray2, Dr Kelly Hill2, Dr Marty Deveney1,3
1PIRSA – SARDI Aquatic and Livestock Sciences, West Beach, Australia, 2PIRSA – SARDI Crop Sciences, Urrbrae, Australia, 3Department of Agriculture Fisheries and Forestry – Marine and Aquatic Biosecurity
Biography:
Kathryn Wiltshire is a research scientist in the Marine Ecosystems program of SARDI Aquatic and Livestock Sciences, working primarily in the field of marine biosecurity. A key focus of Kathryn’s recent research is the application of molecular tools to surveillance, particularly to determine the presence or absence of priority invasive marine species to inform management. Kathryn has led projects to assess the performance of surveillance methods and molecular tools for the detection of invasive marine species, and to map the current and potential range of invasive species using species records and modelling approaches.
Abstract:
The Asian date mussel, Arcuatula senhousia, and the European clam, Varicorbula gibba, are invasive bivalves that are established in parts of southern Australia and pose a risk of spread, particularly by ships’ ballast water. Surveillance for invasive aquatic species (IAS) is important to understand distributions for effective management and to detect new incursions. SARDI developed a molecular surveillance system using plankton samples tested with quantitative polymerase chain reaction (qPCR) assays for IAS of concern that is being applied to inform ballast water management in Australia. Validation of the qPCR assays used in these surveys is important to support management decisions. Assays for 19 key IAS have been developed and validated, with 17 showing good (> 73%) diagnostic sensitivity and very high (≥ 98%) diagnostic specificity. Available qPCR assays to detect A. senhousia and V. gibba, however, while adequately sensitive, were not sufficiently specific. We therefore developed and operationally validated new species-specific qPCR assays for these two invasive bivalves. We used a combination of published sequence data and sequences obtained from Australian A. senhousia and V. gibba specimens and native relatives to design assays. The new assays were applied to genomic DNA and environmental (plankton) samples. Plankton DNA samples included some to which target species tissue was added and archived DNA from previous surveillance. Results were analysed using latent class models to validate performance of the new assays, including quantifying diagnostic performance, and to assess occurrence of A. senhousia and V. gibba at survey locations.