This report provides a summary of work performed to develop methods to quantify Cardicola forsteri and Cardicola orientalis infections in Southern Bluefin Tuna (SBT) and an in vitro study to determine the efficacy of praziquantel as a treatment for C. forsteri infections. The project was also intended to: determine the efficacy of praziquantel as a treatment for C. orientalis infections; determine minimum optimum dose to treat Cardicola spp.;  determine safety margin / display target animal safety; determine ANZECC-compliant environmental trigger value and model environmental release; perform a dose optimisation field study; develop toxicology database; determine withholding period from residue studies; and collate occupational health and safety data. However, due to changing industry practices and subsequent changes in research priorities, this project was ceased and did not address these additional outcomes. Despite this, the project delivered on its overarching aim of optimising the use of praziquantel to manage blood fluke infections, while developing data to underpin the requirements for an Australian Pesticides and Veterinary medicines Authority (APVMA) Minor Use Permit (MUP) application.  Given the outcomes of this project, the APVMA has indicated that they would accept a Minor Use Permit (MUP) application to be submitted for praziquantel. This application would make label claims against C. forsteri alone, with APVMA indicating that adequate supporting data for this application would comprise data on mortality and cardio-vascular health. This fulfils the primary reasons for undertaking this research project.