A researcher's daughterless carp project has stalled because of a lack of funding.
Dr Ron Thresher is now looking overseas for more funding, after breeding 5000 potential carriers of a daughterless carp gene, which are being kept at Auburn University in the US.
About $8 million has been invested in the CSIRO senior research scientist's work, which has been supported by the Invasive Animals CRC and Murray-Darling Basin Authority and is widely seen as the best means of controlling the pest species in Australia.
Dr Thresher said no funding was likely, even though he hoped to screen the experimental carp in coming months during the peak breeding season.
''The message from the Murray-Darling Basin Authority, via the Invasive Animals CRC, is that they are not in a position to further invest in any carp-control work, and for that matter are scaling back their internal fish habitat project altogether. I am now looking for support overseas. Nothing positive yet.''
Dr Thresher said breeding carp that could have only sons would help tip the balance against the freshwater menace, and could potentially have the same impact on cane toads. His research team found genes in a carp's relative, the zebra fish, that were female only and could trigger another gene construct that eliminated the females, turned females into males or made the females sterile.
Sydney Coarse Angling Club regularly catches and releases tonnes of carp in Canberra, and critics say this is a wasted opportunity. They believe the fish should be destroyed in keeping with a project to clean up a section of the Murrumbidgee River.
The club says catching and releasing carp is not illegal, and not returning them to the water could trigger more breeding.
However, in a letter to The Sunday Canberra Times, Gowrie resident Michael Jordan said a sustained attack on carp would have more hope of success if the carp were not returned to the water.