Federal agencies describe carp, which now make up 80-90 per cent of fish biomass in the Basin, as ‘one of the worst introduced pest species in Australia’ due to their degradation of waterways.
NSW Irrigators Council CEO Claire Miller said the impact of carp on habitat and water quality is one of the “greatest ecological threats to native fish recovery and healthy rivers in the Basin”.
“The number of carp spawning is jaw-dropping. It looks like the water is bubbling,” she said.
“We call on the authorities to act promptly.
“Carp control is essential to avoid these floods leaving a lasting legacy of ecological degradation for years to come thanks to carp in plague proportions.”
Moulamein irrigator Jeremy Morton posted footage on social media last week of clouds of carp in a drainage line on his property, near the Neimur Creek.
The video was captioned “this is just one little tiny spot. Imagine how many countless billions have actually bred over the last few months; unbelievable”.
Ms Miller said this explosion of carp should put pressure on the Basin Ministerial Council to look past the simplistic ‘just add more water’ approach when it considers the next steps on the Murray-Darling Basin Plan.
The carp spawning follows hypoxic blackwater events across the basin, in which deoxygenated water from widespread flooding caused fish deaths.
“No amount of buybacks will fix the basin’s biggest ecological threats, with rampant destructive feral species killing native species, wrecking their habitats and water quality,” said Ms Miller.
“If we are serious about looking after these important ecosystems, a health check would quickly reveal invasive species, degraded habitat and water quality should be the priorities for action.”
Speak Up Campaign said what we are seeing is further evidence that the ‘just add water’ approach of the Murray Darling Basin Plan is not working.
Its deputy chair Lloyd Polkinghorne said Speak Up is one of several organisations which have called for greater focus on carp control, but continues to be ignored.
“Six years ago we called for a comprehensive review of basin-wide water use, following a carp breeding explosion and native fish kills from hypoxic blackwater during the 2016 floods,” he said.
“In the current flooding event there are again extreme concerns about the damage being caused by millions of carp, and again we have lost native fish through hypoxic blackwater. Yet we do not get the action needed to address these issues.
“Instead, the focus continues to be around recovering more water which is only going to exacerbate an already dire situation.
“We need to take a more common-sense approach and review the flaws in water management, which have again been obvious during recent floods.”
Speak Up supports the NSWIC’s calls for the Basin Council to look past the simplistic ‘just add water’ approach when it considers the next steps for the Murray-Darling Basin Plan.
It also supports the views of world-leading river scientist Dr John Conallin, who after flood events in 2010-11 and 2016 warned that without a concerted effort to reduce carp numbers we would never get rid of them and “never meet the native fish based outcomes under the Murray-Darling Basin Plan”.
He described carp as “one of the biggest threats we have to native fish recovery because they steal all the food of natives, bully, eat and live where natives should live. They mess up the water quality for native fish.”
Mr Polkinghorne said Speak Up is again calling for a review of water management and the damage caused by excessive water flows, both during flood and non-flood situations.
The group says it must include whether more water needs to be recovered, as proposed under the Basin Plan, amid growing concerns that excessive water delivery will continue to cause more damage, both through carp breeding and further riverbank erosion.
“After more than 10 years of implementation we have seen some positive aspects to the Basin Plan, but there have also been negative unintended consequences which authorities have been reluctant to acknowledge.
“In 2023 we should take off the blinkers and look at the plan in a more holistic way; one that protects our environment and our communities.”
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