Carp control breakthrough under scientists' noses

Jacquelyn Curtis 

Professor Sorensen

19 June 2007: Scientists are close to sniffing out a solution to one of Australia's worst invasive freshwater fish – the carp.

The nose has it – according to the Invasive Animals Cooperative Research Centre (IA CRC) and visiting collaborator Peter Sorensen – who presented findings on the use of sex attractant pheromones to control carp.

Professor Sorensen, from the University of Minnesota, presented his findings together with speakers from the NSW Department of Primary Industries and the South Australian Research and Development Institute (SARDI) as part of the first IA CRC Breakthrough lecture series.

Carp have been dubbed the ‘rats of the river' due to the economic and environmental threat they pose to river-reliant industries such as agriculture, tourism and commercial and recreational fisheries.

Through conducting research on goldfish, a species very similar to carp, Professor Sorensen's work has identified a male derived pheromone which may have “multiple uses in attracting, diverting and removing carp by controlling the responses the female carp has towards males.”

“This is an interesting finding and we have every reason to believe sexually mature male carp in the wild release an attractant to sexually mature females,” Professor Sorensen said. “This is a sustainable strategy we could extract and use to control common carp.”

Through studies of carp in various lakes in Minnesota, Professor Sorensen revealed the rate of adult survival was high; a significant problem considering “carp have infested much of that whole system and dominate the fish biomass” – not unlike the situation in the Murray-Darling Basin waters.

“This recent discovery of a male-derived sex pheromone is far more beneficial in removing the species due to the reproductive implications,” he said.

The program also presented findings on ‘hotspots' work the IA CRC has completed, particularly the finding that carp breed in very few places and are stimulated to breed through environmental and sexual cues.

The research suggests environmental and sexual cues could stimulate carp to migrate to an identified hotspot and be physically removed.

“Sensory assisted removal is realistic,” Professor Sorensen said. “I think we are on the verge of having a real way of controlling carp.”