Scientists target breeding 'hotspots' for freshwater pests

Carp sampling at Dubbo.

Scientists are searching for potential carp breeding sites in inland NSW rivers in order to identify important recruitment ‘hotspots’ for the fish that has become Australia’s number one inland freshwater pest.

Recent good rain throughout inland NSW has led to reasonably high flows in many river systems – and these are a cue for initiating spawning in many fish including the noxious carp.

Research by NSW Department of Primary Industries (DPI) scientists has found that carp do not reproduce throughout entire river systems and that the vast majority of carp breed as a relatively small number of locations.

Sampling for carp larvae was done at, and downstream of, potential carp breeding sites, soon after these high flows passed.

NSW DPI fisheries scientist, Dean Gilligan, said identification of these ‘hot spots’ provides important opportunities for carp control.

Larval carp sampling to identify the most important ‘hotspots’ is being done across the entire Murray-Darling Basin by NSW DPI scientists working with their counterparts from Victoria, South Australia and Queensland.

Dr Gilligan said these locations can then be targeted using a range of control options that are to be identified under a detailed Integrated Pest Management strategy.

The strategy is to be developed by fisheries scientists working under the auspices of the Invasive Animals Cooperative Research Centre.

Dr Gilligan said carp are the most significant pest of freshwater river systems in Australia, impacting on native fish communities, recreational fisheries and riverine environments.

They dominate many river systems, comprising an average of around 80% of the fish biomass in many areas.

Further information

Dean Gilligan, NSW DPI, Narrandera on 02 6959 9031 or dean.gilligan@dpi.nsw.gov.au.

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