Organisers of South Australia's biggest carp fishing competition have been left reeling after more than 16,000 carp were pulled in from Barmera's Lake Bonney in just one day.

The SA Carp Frenzy has been running since 2013, but previous years have only seen final tallies of about 1,800 fish.

Around 500 fishers took part in the 2017 SA Carp Frenzy. ( Supplied: Kym Manning )

"They're very unexpected and quite amazing figures — we haven't even hit 2,000 [before]," SA Carp Frenzy organiser Kym Manning said.

"We had 500 fishermen and we actually pulled out 16,660 carp in nine hours.

"We were just astounded — there were so many little carp, you could barely keep your line in the water."

Carp numbers have exploded throughout the Murray-Darling Basin since a high flow event swept through the system late last year, creating perfect breeding conditions for the introduced species.

The bottom-feeders are often referred to as the rabbits of the river because they rip up and damage native underwater vegetation, reducing water quality, and suitable breeding habitats for native fish.

"They're like flies at the moment, there are so many of them," Mr Manning said.

"People were catching hundreds which is just ridiculous.

"We're still shaking our heads."

Mr Manning said he estimated the event had raised about $10,000, which would go towards funding projects developed by the local community.

He said the fish caught during the 2017 SA Carp Frenzy would be taken and used by fertiliser manufacturer Charlie Carp, as they are not good eating.