The foundation urged the government to take immediate steps to control the number of European carp in Victoria waterways.

It is concerned climate change could be helping carp spread further through Australian rivers.

Foundation managing director Allan Hansard said carp are Australia’s worst established pest in rivers.

“They rival the crown of thorns starfish as an environmental threat and in their ability to destruct our unique aquatic ecosystems,” he said.

“Scientists have revealed that carp and other invasive fish species now make up to 80 per cent of the fish biomass in the Murray-Darling, and up to 93 per cent in some areas.

“We know carp are part of the reason why our native species like the iconic Murray cod and yellowbelly are struggling in many parts of the system, and in other parts, they have disappeared completely.”

Although he said there was no proof yet global warming was affecting carp levels, Mr Hansard did say warmer waters could be making it easier for carp to adapt to traditionally colder areas.

“Scientists haven’t been able to confirm our suspicions, but we think that the warming effect of climate change on our river systems is increasing the ability of carp to adapt and populate colder water river systems and even estuary systems,” he said.

“Recreational fishers are reporting catching carp where they previously haven’t been caught, including our cold water rivers and even our saltwater estuaries.

“Governments need to act now to stop the invasion of carp in our waterways as the current set of tools such as electrofishing, netting and cage trapping have proven ineffective.

“Our concerns are that if left unchecked carp will continue to dominate our inland and estuary waterways and our iconic native fish species will continue to struggle or could even become a thing of the past.”