BigDog23 you seem to be a victim of the dribble which has been fed to the australian public for decades regarding the impact of carp.
Carp are easy to blame for the sad state of australian freshwater species.
The truth is that decades of mismanagement of waterways has resulted in what you see now. Carp are an adaptive species which can easily survive the poor conditions created by erosion, pollution and deliberate alteration of natural flows, and that is why they have flourished. They have nothing to do with muddy water, or how do you explain the crystal clear lakes in Europe and other places like south africa and america which are full of carp?
When the Koi Herpes Virus is released as planned in 2018 millions of of dead carp will quickly overwhelm the meagre freshwater supplies, oxygen levels will fall rapidly under the influence of rotting fish and native species will be wiped out. The water will quickly become unfit for any domestic use. The puny $15 million allocated to the cleanup will come nowhere close to what is needed. After about a week dead fish sink to the bottom and then it will be too late. The rumors of mobilizing locals to pick up putrefying rotting fish carcasses is a fantastical dream.
The KHV is highly virulent and spreads very quickly. Mortaility is within one week. I don't think the release of a new organism into waterways is the solution. They tried it with Myxamatosis in rabbits and it has not worked. They tried it with cane toads to control the native cane beetle and it has been a catastrophe. Carp has been in australia for 150 years and is now deeply entrenched in the local eco-system. As you say it makes up most of the biomass. What will the effect on wildlife (birds, other predatory fish species, animals) be if a well-established species is removed? No research has been done, no projections are available. In addition to all that, if the virus escapes to Europe the effect on the billion dollar carp fishing industry will be calamitous. And let's not forget Asia where carp is a major food source. If KHV becomes widespread in Australian freshwater as planned the likelihood for this happening becomes much more substantial.