Carp (Cyprinus carpio) are one of 34 freshwater fish introduced into Australia which have established self sustaining populations (Lintermans 2004). Now widespread throughout the inland waterways of south-eastern Australia, carp are widely believed to have detrimental effects on native aquatic plants, animals and general river health, particularly through their destructive feeding habits (Koehn et al 2000, Smith 2005, Miller and Crowl 2006).
Public concern that the high numbers and widespread distribution of carp pose a major threat to aquatic ecosystems has resulted in increasing interest from catchment management groups to actively manage carp. Whilst research is progressing to develop large scale methods of carp control, there is a pressing need to firmly establish the benefits of existing methods that can be applied by local communities and landholders. There are a number of commonly used fisheries techniques that can help manage localised carp populations when used in an integrated manner. These tools vary greatly in their effectiveness, species specificity, cost and the technical skill required. This report compares these attributes for some of the techniques most commonly used to manage carp at a smaller scale.
Catch per unit effort (CPUE) was calculated as the carp catch resulting from each man-hour of effort each time a technique was implemented. Standardising in this manner enabled direct comparison between techniques. No fiscal value was placed on each man-hour due to differences in operator skill level requirements between techniques. Techniques were initially examined individually to calculate catch efficiencies and effectiveness across a range of carp densities and habitats. Direct comparisons were also made between six techniques applied concurrently at eight sites. Annual surveys were conducted to examine how long removal activities had an impact on carp populations at a number of treatment and control sites.
Electrofishing was the most efficient technique and captured the widest size range of carp. The second most efficient technique was the hopper trap which was developed as part of the project. Gill-nets, seine nets, bait traps, fyke nets and angling were also assessed.
This project demonstrated that a range of currently available, generally low cost techniques can be used to capture carp. The effectiveness of these techniques varies with habitat type, carp density, carp size and the presence of non-target species. No single technique is appropriate in every scenario and thus a combination of techniques in an integrated approach is required. Organisations wishing to employ these techniques will need to seek permits and training from the appropriate regulatory bodies for their area.
Download the full report by clicking on the cover image above right or the link below.
|Author||Norris A, Hutchison M, Chilcott K and Stewart D|
|Publisher||Invasive Animals CRC|
|Institution||Department of Employment, Economic Development and Innovation, QLD|
|ISBN/ISSN||Web ISBN: 978-1-921777-76-9|
PestSmart toolkit: Carp - www.pestsmart.org.au/pest-animal-species/european-carp/