Pacific Oyster Mortality Syndrome (POMS) is a disease caused by Ostreid Herpesvirus type 1 (OsHV-1) microvariant, which causes rapid high mortalities (up to 100%) in Pacific oysters. POMS has caused significant economic impacts to the oyster growing industry in parts of NSW and Tasmania. It was first detected in South Australia in early 2018 when emergency response containment measures were taken. However, the lack of accurate epidemiological information forced a conservative approach. This project addresses this lack of information by modelling the dispersal of OsHV-1 particles from various locations around South Australia to determine epidemiological units aimed at improving surveillance, biosecurity zoning and future emergency responses. It will demonstrate how hydrodynamic model outputs of predicted viral particle dispersal can be used to develop a risk-based surveillance design for the detection of OsHV-1.