Carp (Cyprinus carpio) are one of at least 34 freshwater fish species introduced into Australia that have established self-sustaining populations (Lintermans 2004). Carp are now the most abundant large freshwater fish in the Murray–Darling Basin, comprising up to 90% of fish biomass in some locations, and are the dominant species in many fish communities in south-eastern Australia (Reid and Harris 1997, Brown et al 2003).
Many community groups are concerned about the detrimental impacts carp are having in their local waterways, and some groups have organised ‘fish-out’ events to actively address the issue. It is well known that fishing pressure can run down fish stocks in a river (Templeton 1995), but it remains unclear as to whether community-based fish-out events have a significant impact on their target species. This project quantified the percentage of carp population removed in three ‘fish-out’ competitions in the Queensland portion of the Murray–Darling Basin.
At each competition, a series of monitoring sites were established. Before the events began, carp were captured at these sites via electrofishing, marked with dart tags and released. The competition catch and post-event electrofishing enabled the carp population size at each site to be estimated from tag return rates using the Lincoln–Peterson method. Population reductions from both the competition angling and the subsequent electrofishing were calculated. A total of 1006 carp were tagged with an overall tag return of 12% for the whole project.
The results demonstrated that carp angling competitions are not very effective as a direct form of carp management. The removal efforts occurred over large areas, resulting in low angling pressure and removal rates. Population reductions were observed in the range of 0.5%–1.8% across the competition areas. In comparison, removal via boat electrofishing resulted in a carp population reduction of 8.3%–16.1%. When compared to electrofishing, the catch per unit of effort (CPUE) of competition angling was found to be nearly 100 times less in terms of carp caught per man hour. We conclude that the way these events are currently run, they are unlikely to have any significant impact on local carp population numbers.
Carp fishing competitions do, however, have a range of less tangible management benefits. The events help educate the wider community on the detrimental impacts of pest fish, raise awareness and ownership of the pest fish issue and provide a social focal point for smaller regional communities. The competitions can also generate money, which can be directed into native fish restocking, river restoration or funding contractors to remove carp in high-value areas.
|Secondary title||PestSmart Toolkit|
|Author||Andrew Norris, Keith Chilcott and Michael Hutchison|
|Publisher||Invasive Animals CRC|
|Department||Queensland Department of Agriculture, Fisheries and Forestry|
|Documents||The role of fishing competitions in pest fish management [ 960kb PDF ]|