They are known as the rabbits of the waterways, but it is hoped a new biological control could soon reduce carp populations in the Hunter by up to 80 per cent.

Since 2006, scientists in Victoria have been trialling the virus which affects their gills and prevents their ability to breath.

Considered a major problem in Australia, carp have destructive feeding habits which stir up sediment and make it difficult for other fish and birds to feed.

Primary Industries researcher Dean Gilligan says the virus is only lethal to carp.

“There is evidence that some other species may be able to carry the virus but, if they carry the virus they’re not affected so they don’t show signs of the disease, it’s only carp that show disease,” he said.

“We’ve also tested a bird and a mammal, just representative to test whether there’s any effect on those groups, and we knew there wouldn’t be, but obviously those results were positive as well.”

Dr Gilligan says the research is now coming to an end, and the results are positive.

He says while it will not eradicate the introduced species, it will serve as an effective suppressant of population numbers.

“There will always be some individuals that are resistant, and if they survive an outbreak they’ll be immune for a period of time,” he said

“But the data from initial outbreaks is that there’s an 80 per cent or greater initial knockdown in the population, then there’s ongoing chronic mortality.

“But, that said, evolution is unavoidable, just likes rabbits evolved a resistance to myxomatosis.”