A competitor releases a large carp back into the lake near Bowen Park during the Canberra Classic fishing competition on Friday, December 7.

A competitor releases a large carp back into the lake near Bowen Park during the Canberra Classic fishing competition on Friday, December 7. Photo: Rohan Thomson

The ACT government has declined to explain a conflict between its carp reduction strategy and legislation in both the territory and NSW which does not prohibit releasing captured fish back into lakes and streams.

The Canberra Times reported on Monday carp were being returned to Lake Burley Griffin despite attempts to reduce numbers in the Murrumbidgee River.

A demonstration reach, a section of a waterway or wetland where a number of management interventions are applied to showcase the cumulative benefits of river rehabilitation on native fish populations, has been established to encourage native fish and research ways of restricting carp.

When asked why a Sydney fishing club could return carp to the water, despite a recommendation in the Upper Murrumbidgee carp reduction strategy against such practice, the Environment and Sustainable Development Department said:

''All anglers are allowed to release carp at the point of capture. It is illegal to move them between waterways (alive or dead). Anglers are encouraged to humanely destroy carp and dispose of them appropriately rather than leaving them on the banks.''

In September the ACT government announced a taskforce was proposing a $60 million project to clean up Lake Burley Griffin, including for the first time sustained culling of the carp population. The report is still under consideration.

Fisheries, angling and noxious pest experts concede it is impossible to eradicate the exotic pest, because numbers quickly return from breeding, surrounding waterways, waterbirds and people illegally releasing noxious fish.

Sydney Coarse Angling Club spokesman Howard Hill said carp was the most-eaten freshwater fish in the world. ''The Chinese and Vietnamese put them in their rice paddies and have fish and rice. It's protein with their rice.''

Mr Hill said many nationalities regarded carp as an excellent table fish, while in the eastern states of Australia many people were still coming to terms with how to live with the problem.

Capital Region Fishing Alliance president Shane Jasprizza said ''carp out'' events, where carp are caught and killed, educated people and gave participants a feeling they were helping with the fishery.

On occasion he did not kill every carp he caught.

If he hooked a whopper carp at Lake Tuggeranong he would release it in the hope of catching it again.

''You have people opposed to killing for the sake of killing, conservationists. Realistically, we are still catching as many carp as before. We don't pretend that we are getting rid of them. Every little bit might help. You will never get rid of them.''

Electrofishing in Lake Burley Griffin earlier this year, ACT environment staff caught 395 fish, 57 per cent carp and 34 per cent redfin. Of the remaining fish, a few Murray cod and golden perch were found. The survey team recommended continual stocking of native fish and more electrofishing to assess effectiveness of stocking fish with natives.