The Federally funded National Carp Control Plan (NCCP) is considering the feasibility for carp biocontrol using carp herpesvirus CyHV-3, in order to restore native freshwater biodiversity.
It is well recognised that invasive carp (Cyprinus carpio) can potentially harm native ecosystems and the concept of carp biocontrol warrants rigorous scientific consideration. Research funded though the NCCP is currently examining some aspects of this to inform a recommendation in late 2019 about proceeding with biocontrol using herpesvirus. However, despite this research, important uncertainties will remain, owing to the limited time and funding available, and the complex nature of the problem itself – whereby further complexities and uncertainties are uncovered as the research proceeds.
Key uncertainties and knowledge gaps which we consider to be important for informing the recommendation can be summarised into three themes: the generality of scientific understanding of the damage carp cause in Australian settings, the potential effectiveness of herpesvirus as a biocontrol measure, and possibilities for unintended negative outcomes from its deployment. We explore these issues, with focus on intermittent rivers of the northern Murray-Darling Basin.
It is important to recognise that impacts of carp on Australian native biodiversity are relatively static, carp having expanded to their major current range decades ago. The problem is not worsening. Likewise, the potential of the herpesvirus for biocontrol would not diminish if the research and decision time frames were extended. The magnitude of the uncertainties and risks warrant a longer-term research programme beyond the current NCCP commitments. Because of the potential risks and irreversibility of introducing this virus into Australia, the onus is on the science to provide robust evidence that risks will not manifest and that desired benefits will be realised. At present we do not believe the science is comprehensive enough to do this.