Controversy has swamped the federal government’s plan to release carp herpes virus into inland waterways, but key backers maintain their support for the scheme to eradicate the highly damaging feral fish.
Matt Barwick, national coordinator for the $15 million National Carp Control Plan, resigned last week just days after an independent scientific adviser criticised the scheme and the government delayed the planned release of the virus to the end of next year.
The scheme was kicked off by former Water Resources Minister Barnaby Joyce to develop a biocontrol for feral carp, like the use of myxomatosis to control rabbits, through the use of the lethal carp herpes virus.
Last week scientific adviser to the program Sydney University Associate Professor Joy Becker argued that while mass carp deaths would likely occur after the virus was released, the fecund fish would soon breed up again.
“Matt Barwick deserves a defence and that’s why I am here today. His resignation, because it’s so well correlated with the attack on the (plan to release) virus, a person who has done years of work has resigned because of a separate view.”
“There’s little evidence to suggest that we will see repeated outbreaks (of the virus) of a magnitude to counter the reproductive potential of the surviving carp,” Dr Becker said.
A range of concerns have emerged over the herpes virus release, such as the impact of large amounts of dead fish on water quality and biosecurity concerns for farmed fish in developing nations, where carp are a significant protein source.
However, fish ecology expert Dr Martin Mallen-Cooper, Adjunct Research Professor at Charles Sturt University, said despite Dr Becker’s findings the potential gains in inland waterways from releasing the virus were so significant that it must be considered in full.
“I take Dr Becker’s comments seriously, and I would definitely investigate them. But that’s one viewpoint and I wouldn’t abandon the program,” Dr Mallen-Cooper said.
“The benefits for the Murray Darling Basin’s native fish and aquatic ecosystems are huge and we need to assess them thoroughly.”
Carp have decimated native fish since they exploded across the Murray Darling Basin and are estimated to comprise 90 per cent of the total weight of fish, or biomass, in the river system.
Carp are hardy, out-breed native fish, eat their spawn and crowd them out of habitat.
The economic impact of carp damage is estimated at $500 million.
Dr Becker said the natural emergence of the Epizootic Haematopoietic Necrosis Virus (EHNV) killing feral Redfin perch in Australian freshwater waterways in the 1980s was a good comparison to draw with the carp herpes virus.
Fish that have natural immunity to the virus survive the initial outbreak breed up and found a population that ultimately outlives the contagion’s effectiveness.
“The EHNV does well in wider temperature zones than the carp herpes virus, which means it’s better at causing epidemics.
“But our work shows that in Blowering Dam, for example, there were EHNV outbreaks every year initially but that’s slowed significantly. An outbreak hasn’t been reported since 2010.”
Mr Barwick’s resignation is not expected to delay the release date of the virus.
Agriculture, Fisheries and Water Minister David Littleproud said Mr Barwick had done a “fantastic job” and said research showed the virus only impacted carp.
“Mr Barwick’s resignation is not expected to change the timeline for the project,” Mr Littleproud said.
“The virus has been tested on countless species of native fish, none of which have caught the virus.”
Mr Joyce said it was a “great shame” to lose Mr Barwick.
“It’s incredibly disappointing, after so many years of research that while they’re not saying the carp herpes virus will cause problems to other fish, they just don’t think it will kill enough carp quickly enough,” Mr Joyce said.
“If we had that attitude with the myxoma virus with rabbits, we’d still be discussin how we get rid of one of the largest rabbits plagues in the history of the world.
“To try and make the perfect the enemy of the good i think is an anachronism.
“Matt Barwick deserves a defence and that’s why I am here today
“His resignation, because it’s so well correlated with the attack on the (plan to release) virus, a person who has done years of work has resigned because of a separate view.”
The story Carp herpes support flows as controversy swamps ‘Carpinator’ first appeared on Farm Online.