Hundreds of people from across Australia have helped to remove thousands of carp from an iconic South Australian lake, in an attempt to put a dent in the pest fish's population.
Carp boomed after extensive flooding throughout the Murray-Darling Basin system in late 2022 and early 2023, including in SA's Riverland region.
Griffith University Australian Rivers Institute researcher Mark Kennard said while numbers were already high, recent floods saw carp populations grow to astronomical levels.
He said the National Carp Control Plan found the national biomass of carp in Australian waterways could range from 200,000 to 1 million tonnes under ideal breeding conditions.
"Since the floods in the Murray Darling Basin, there's extremely high carp biomass and numbers, so it's a concern for the native species and the rivers we care about," Professor Kennard said.
"They degrade water quality, alternative habitats for species like crayfish, Murray cod and golden perch and can exacerbate impacts of algal blooms.
"There's no doubt they're a real problem but coming up with a solution is a challenge."
Local fisher stirs up carp frenzy
The Carp Frenzy fishing event, born in the Riverland 11 years ago, was one regional fisher's creative solution to get his community involved in reducing the pest species.
Kym Manning said the fishing contest, which encouraged people to catch as many carp as possible in one day, was a sustainable way of helping to drive down fish numbers.
"All carp caught get put on an ice slurry and chilled down and sent to a local fisherman’s freezer … before they’re sent off to Deniliquin and turned into fertiliser," he said.
Mr Manning said the annual competition held on the shores of Lake Bonney continued to grow, with more than 800 people travelling from New South Wales, Victoria and SA to take part this year.
"We caught around 5.7 tonnes of carp in total, which is somewhere between 15,000 to 18,000 fish," he said.
"After the floods, a lot of the campsites haven't re-opened around the lake yet, but people turned up and supported the event … and this was the best one yet."
Innovation needed: Researcher
Barmera resident Amber Perry said it was the eighth carp frenzy she and her family had taken part in as it was a great opportunity to educate her children on healthy waterways.
"Me and my family are a big fishing family … and I think it's the best way to help get rid of carp," she said.
"It gets everyone out having fun.
"My kids even out-fished me."
Professor Kennard said more innovative approaches like carp fishing competitions and installing carp fishways were needed to help reduce populations.
"The carp herpes virus was put up as a magic solution under the National Carp Control Plan," he said.
"While it could potentially work, it's going to require a combination of efforts.
"We also need to look at continuing to restore and rehabilitate native fish habitats...alongside carp eradication," he said.
