Koi Herpesvirus: Its Potential as a Biological Control Agent for Carp in Australia

We are investigating whether koi herpesvirus is a potentially good biological control agent for carp (Cyprinus carpio) in Australia. Our initial results show that:

 

• Mortality is higher in juvenile compared with older carp.
• Carp-goldfish hybrids are less susceptible to KHV, and we are currently determining the prevalence of hybrids in selected wild populations of carp in Australia.
• We are examining wild-caught immature carp for less virulent cross-reactive viruses that may confer protection from KHV.
• KHV has been found to have no effect on three native fish species that have been tested – Murray cod, golden perch and silver perch. Two other species are currently being tested.

• Infected carp excrete KHV for 1 to 2 days before clinical signs of disease in the fish.

We have also reviewed past successful viral biological control programs of vertebrate pests, and have concluded that management and development of a successful program is underpinned by (i) a thorough understanding of the biology of the target species and of the viral epidemiology; (ii) an integrated control program involving both the virus and other new and existing control methods; and, (iii) a post-release assessment of the ecological benefits of the control program.