Project number: 2000-182
Project Status:
Budget expenditure: $174,312.00
Principal Investigator: John Diggle
Organisation: Inland Fisheries Service (IFS)
Project start/end date: 23 Nov 2000 - 30 Aug 2004


Development of control techniques for carp has been given high priority in FRDC and CCCG reviews of Australia’s carp problem. Carp control is now hampered by a lack of techniques. Eradication is considered to be feasible only in small water bodies that can be poisoned or drained. Genetic and physiologically-based tools may be developed over time to control, and perhaps eradicate, carp from larger water bodies. However, this technology will be expensive to develop and public safety concerns may have to be addressed. What is lacking from carp control are techniques that can be used in larger water bodies. We propose here to modify a standard control technique (physical removal through fishing) so that it can be used to eradicate carp from larger water bodies.

Eradicating carp from Tasmania will provide the basis to rehabilitate what were once two of Tasmania’s finest trout fishing lakes contributing a $30 million fishery comprised of a mix of recreational fishers, commercial fishing guides, tourism operators, and equipment manufacturers. At the same time we will remove the risk of carp escaping from these lakes and causing extensive environmental and habitat damage to lowland rivers, lakes and reservoirs with the resulting loss of freshwater habitat and water quality.


1. Use existing Lake Crescent carp capture data to develop a risk assessment model (based on characteristics of recorded catches) that will determine the number of male fish to leave in Lake Crescent while fishing down the females, and the period of fishing required to ensure that the Lake is free of female carp at a level of risk required by managers.
2. Conduct the first three years of a strategic fishing plan to eradicate carp from Lake Crescent.
3. Interpret catch per unit effort and mark and recapture data collected since the start of the fishdown (1995) to develop a population model and determine the population characteristics of the Lake Crescent and Lake Sorell carp populations.
4. Use the models developed in steps 1 and 3 to determine the number of male carp to add to Lake Sorell as female aggregators, and the strategic fishing plan necessary to achieve eradication of females from this lake at the level of risk required by managers.
5. Monitor the results of the selective fishdown of male carp. Determine the extent to which they validate the model predictions and any problems or concerns in using selective removal of males to eradicate the population.
6. Ensure that the successful results get distributed widely to promote the mindset that feral fish can be eradicated and to provide the techniques for that eradication.

Final report

ISBN: 0-646-435-99-X
Author: John Diggle

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