Case study: Queensland carp fishing competitions

Carp fishing competitions, commonly known as carp fish-outs or musters, are popular in many communities. These events are usually organised and funded by local fishing clubs, and people see them as a fun way to help deal with the pest fish problem,  and/or to raise money for the restocking of native species or other community-based projects. Some community carp musters may be incorporated into large-scale waterway rehabilitation projects managed by state fisheries agencies and catchment management authorities.

Although fishing pressure can run down fish stocks in a river, research and anecdotal evidence suggest that carp reductions from a fish-out event may not result in a lasting reduction in carp numbers. This case study assesses the value of fishing competitions as a management option and estimates the percentage of carp populations removed in three of the six carp fishing competitions held in southern Queensland in 2007 and 2008.

The Queensland Murray–Darling Committee (QMDC) helped establish and run the 2008 Regional Carp Busters Series, which comprised six carp fishing competitions held throughout the year, including:

  • the inaugural 2007 Goondiwindi Carp Cull
  • 2008 Surat Carp Busters Family Fishing Competition
  • Thallon Carp Comp 2008
  • 2008 Goondiwindi Carp Cull
  • 2008 Mungindi Carp Busters Fishing Competition
  • the 2008 Dirranbandi Carp Comp.

Aim

The aim of the 2008 Carp Busters Series was to combat the impacts and spread of carp, through community-implemented activities at a regional scale. Participants were encouraged to attend more than just their local carp fishing competition.

Partners and partnerships

The Goondiwindi Carp Cull was established by Goondiwindi District Promotions, local fishing clubs and the then Queensland Department of Employment, Economic Development and Innovation (DEEDI). Principal funding for the event was provided by the Queensland Murray–Darling Committee (QMDC) and the Invasive Animals Cooperative Research Centre (IA CRC), with smaller contributions from local retailers.

Process

The inaugural Goondiwindi Carp Cull focused on the capture of carp along the McIntyre River and its backwaters, with a small section for the catch and release of native species. Registrations were taken from 169 competitors, coming from throughout the Darling Downs, Western Downs, northwest New South Wales and Brisbane.

The second event of the series, The Thallon Carp Comp 2008 was held along a 6 km stretch of the Moonie River adjacent to the Thallon township. The competition area was a closed system, with a causeway marking the upstream boundary and a dry stretch below the town weir forming the downstream margin. No flow occurred through this region during the competition. The competition was well attended, with 305 anglers registering.  Competitors came from a wide area, with on-stream camping encouraging many to make the effort to attend.

The 2008 Goondiwindi Carp Cull was again held on the McIntyre River, but switched to a carp-only competition. The competition area was reduced in size and included the off-river lagoon at Rainbow Reserve, where participants could camp and fishing efficiency could be evaluated in a closed environment. The reduced area resulted in the majority of anglers fishing within monitored sites. In total, 242 individuals and six teams participated in the fishing competition over the two and a half days.

Features of the study

A series of monitored sites were established at each competition, including fishing sites and non-fishing sites. One to two weeks before the events began, each section was electrofished for three hours, and all carp caught were measured to fork length (FL), dart tagged and released.

Carp population size was estimated based on tag return rates from the competition catch and post-event electrofishing. With these estimates, angler and electrofishing removal efficiencies were calculated using catch per unit effort (CPUE).  Prizes were offered for the capture of tagged fish to encourage participants to fish in these areas, which increased angling pressure and led to more accurate estimates of angler effort.

Twice-daily boat and car-based inspections were used to count the number of anglers at each location to determine angling pressure. Calculations of angling effort (man hours) were based on the assumption that the average participant fished for eight hours during daylight and a further two hours during the night for each full day of competition (ie a total of 18 hours).

A  total effort of 14 fishing hours per angler was used to estimate the catch per hour at the 2007 Goondiwindi competition, due to a different start and finish time.

Results

The 2007 Goodiwinidi Carp Cull: During competition, anglers caught 138 carp ranging in size from 140–706 mm FL. Sites adjacent to barriers across rivers, enclosed lagoons and dams, or those adjacent to irrigation inlets provided the highest catch per angler.

Two tagged carp were caught during the competition period, but the average population reduction per site was estimated at only 0.5%. The estimated total fishing effort was 2366 angler-hours, giving a CPUE of 0.058 carp per angler-hour.

Post-competition, three people electrofishing for four hours at each site (84 man-hours), caught 437 carp (23 tagged) and 112 goldfish. The carp ranged in size from 56–654 mm FL, and the electrofishing carp CPUE was 5.202 carp per man-hour.

The 2008 Thallon Carp Competition: Anglers caught 170 carp during competition, ranging in size from 113–619 mm FL. Six tagged fish were recaptured. The estimated total fishing effort was 5490 fishing hours, giving a CPUE of 0.031 carp per angler-hour.
Post-competition elctrofishing for three hours per site (117 man-hours) caught 1179 carp (56 tagged) and 73 goldfish. The carp ranged in size from 74–658 mm FL, and the electrofishing CPUE was 10.076 carp per man-hour.

The 2008 Goondiwindi Carp Cull: Anglers caught 149 carp during two and a half days, ranging in size from 120–670 mm FL. Eight tagged fish were caught during the competition, with another two caught before the follow-up electrofishing. The estimated total fishing effort was 4068 angler-hours, giving a CPUE of 0.037 carp per angler-hour.

Post-competition, 117 man-hours of  electrofishing caught 667 carp (23 tagged) and 112 goldfish. Unfortunately one site could not be resampled due to extremely low water levels. The carp ranged in size from 111–656 mm FL, and the electrofishing CPUE was 5.701 carp per man-hour.

Overall: Average carp population reductions across competition areas for angling and electrofishing followed a similar trend in all competitions.

  • Angling pressure only reduced carp populations by 0.5–1.8%. In contrast, electrofishing resulted in greater reductions (8.3–16.1%). At individual sites, population reductions as high as 8.3% were observed from angling, and as high as 32.1% from electrofishing.
    A total of 1034 carp were caught by electrofishing just before the three competitions, with 1006 of these of suitable tagging size (>150 mm FL).
  • A combined total of 740 anglers registered for the three competitions. The anglers fished with a combined total effort of 11,924 man-hours, catching 457 carp (18 tagged).
  • Post-competition electrofishing with a combined total effort of 318 man-hours caught 2283 carp (102 tagged), along with 297 goldfish.
  • The overall tag-return was 12% of those initially tagged. This level of recapture allowed the local carp populations to be estimated to an accuracy of ± 19%.

Outcomes

Tag returns were far greater for electrofishing than for angling at all three competitions, reflecting the difference in relative catch rates. Electrofishing captured a far greater range of sizes and was particularly effective on small fish. Angling did not capture the smaller fish. The results demonstrated that carp angling competitions are not effective as a direct form of carp management. The catch per unit effort (CPUE) of competition angling was nearly 100 times less than electrofishing.

Benefits of carp fishing competitions

Of the range of possible carp management options currently available, most require specialised equipment and expertise, and few can be implemented by community groups. The results clearly indicate that the angling competitions have a negligible impact on the local carp populations. However these events can still be a valuable management tool.

Community-based carp fishing activities bring together a cross-section of people from the local and extended community, and provide a forum for government agencies and natural resource management groups to educate the wider community on the damage caused by pest fish. They also raise awareness and ownership of the pest fish issue and promote community stewardship of water resources. Carp fishing competitions also attract a good deal of media coverage, which helps promote carp-related issues to a broader audience.

Many competitions raise a profit, which is typically re-invested in local community projects or restocking of native species for recreational angling. Competitions can also be used to raise money to fund carp control. For example, the charge of hiring an electrofishing boat and crew is around $2500 per day. If a competition raised $7500, such a crew could be hired to remove carp for three days at priority sites. Alternatively, the revenue raised could be invested in equipment to aid carp management undertaken with local authorities. For example, the money could assist in installing and maintaining carp separation cages in fishways at weirs, or screening of inlets into carp-free wetlands.
Many events are held in small regional towns and become a key social event for the region. Attracting entrants from out of town generates significant income that helps stimulate the local economy. This can be an important factor for organisations considering investing in fishing competitions, as their investment can result in a broad range of benefits.

Fishing competitions for carp control

Carp removal efforts through the angling competitions occurred over large areas, resulting in low angling pressure and removal rates. Competitions do not remove an adequate proportion of the carp population to reduce negative impacts. The mean numerical reduction to local carp populations from the angling competitions was only 1.3%. Even the electrofishing removals would have only had a small impact, with the mean numerical reduction being only 12.6%. These figures are far lower than the 90% biomass reduction required for improvement of river health.

The chance of that proportion of carp actively feeding and being line-caught during a fishing competition is extremely low, even if the population is small. Additionally, angling does not target all size classes of fish. Gear, bait and angling locations all restrict the size of carp that can be caught. Few fish under 120 mm are caught by angling. Carp in this region of Queensland, in the McIntyre, Balonne and Moonie Rivers, are sexually mature at fork lengths as low as 230 mm. Fish escaping an angling event one year can grow from less than 120 mm to more than 230 mm FL in good conditions. Thus, small carp that have escaped removal may have the opportunity to reproduce between annual competitions.
Most competition areas involve open waterways where immigration can easily occur. Even if competitions achieved meaningful population reductions, immigration of carp from nearby waterways could dilute the results.

Conclusion

Fishing competitions are unlikely to have a significant impact on local carp population numbers, and are unlikely to reduce the level of damage caused by carp. Repeated competitions would have a greater impact, but because the reductions at each event are so small, any long-term benefit is unlikely. Like other pest management techniques, competitions are most likely to have an impact in closed systems where immigration cannot occur.
Carp fishing competitions do, however, have important social and economic benefits. They provide an opportunity to educate the wider community about the detrimental impacts of pest fish, and raise awareness and ownership of the pest fish issue. These competitions also provide a boost to smaller regional communities and can generate income that can be directed into carp control activities, such as native fish restocking, river restoration or the commercial removal of carp by electrofishing contractors.
 

Author Invasive Animals CRC
Year 2014
Publisher Invasive Animals CRC
Pages 4
ISBN/ISSN PestSmart code: CPCS2
Control method Fishing
Region QLD
Documents

CPCS2 PestSmart case study: Queensland Carp Fishing Competitions   [480 kb PDF]

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