Australia’s Carp population breathed a collective sigh of relief when the National Carp Control Plan (NCCP) was publicly released on 3 November 2022, as it appears the release of the Cyprinid herpesvirus 3 (CyHV3 or the carp virus) is uncertain, or years away at best.

The NCCP has been six years in the making, although the CSIRO has been investigating the potential of CyHV3 to control Australia’s Carp population many years earlier. While the CSIRO’s earlier work identified the potential of CyHV3 to reduce or eradicate Australia’s carp population, the NCCP quantifies the extent to which this might happen, identifies what risks need to be addressed, and applies this knowledge to develop a strategy to deploy the virus and manage the risks involved.

The delivery of the NCCP is only the first stage of the process to consider the feasibility of any future release of the virus as a biocontrol agent for carp. The NCCP recommended further research and planning be carried out to address some of the uncertainties still remaining under the Plan. Commonwealth, State and Territory governments then need to decide on whether to proceed with the NCCP.

The decision on whether to release the carp virus in Australia will be one of the biggest things to happen to our environment in many generations. The recreational fishing community will be impacted by whatever decision is made and, anglers need to understand what is in the plan and the opportunities and risks it presents.

 

Contents

1. About this article 

2. Background 

(a) Early work prior to the NCCP 

(b) Establishment of the NCCP 

(c) Delays and criticism of the NCCP 

3. The effectiveness of CyHV3 as a biocontrol

(a) Potential for genetic resistance to CyHV3 

(b) Reductions of 40% to 60% expected 

(c) Latency and recrudescence 

(d) Complementary measures

(e) Further research about the effectiveness of the virus recommended

4. Risks associated with releasing CyHV3

(a) Risk of infection of species other than carp 

(b) Environmental and water quality risks

5. Implementing the National Carp Control Plan

Phase 1. Planning 

Phase 2. Initial deployment of the virus 

Phase 3. Post-deployment 

Phase 4. Completion. 

6. Cost of implementation 

7. Overseas developments 

8. Conclusion 

9. Further reading

1. About this article (return to contents)

Before proceeding further, this article is based mostly on the contents of the NCCP and is not an independent review of the Plan.

Rather, this article’s purpose is to convey the contents of a complex 120 page document into plain English and with as little technical and scientific jargon as possible.

This article also builds on earlier research of scientific papers, media reports and other information used for the following articles previously published on the Canberra Fisherman’s Club website:

Much of the content of those earlier articles is still current. Accordingly, the scientific evidence set out in the NCCP provided few surprises. This made it unnecessary to update those earlier articles.

This also reduced the need for more detailed explanation of the scientific evidence in the NCCP and readers still having questions can look to the earlier articles for further information.

2. Background (return to contents)

(a) Early work prior to the NCCP

The first CyHV3 outbreak occurred in Israel and the USA in 1998, and the virus was also detected in preserved tissue samples taken from a mass carp mortality in the UK in 1996. The virus has since spread to over 30 countries in Europe, Africa, Asia and North America. It has not yet been recorded in Australia.

The CSIRO began investigating CyHV3’s potential to address Australia’s carp problem, with the CSIRO-Australian Animal Health Laboratory in Geelong publishing a paper on this topic in 2007 and giving a presentation on its research in 2013. The Invasive Animals Cooperative Research Centre published a report in 2013 outlining the Commonwealth, State and Territory statutory processes required before any release of CyHV3 could occur.

(b) Establishment of the NCCP

NCCP workshop photo

NCCP stakeholder workshop, Canberra, 19 February 2018, co-hosted by the National Carp Control Plan (Matt Barkwick) and the ACT Government (Allison McInnes).

In May 2016, the Australian Government commissioned the Fisheries Research and Development Corporation (FRDC) to develop the NCCP to assess whether the virus could control Australia’s carp population.

The FRDC worked with Federal, State and Territory governments agencies as well as 11 national and international research institutions and over 40 research scientists. The research involved 19 peer reviewed studies and numerous planning investigations considering various aspects of carp biocontrol. The FRDC also ran a series of community workshops and published regular newsletters and the outcome of its scientific research on the NCCP website.

Given the Canberra Fisherman’s Club membership’s level of interest in the potential use of CyHV3 to control Australia’s carp population, a Q & A article drawing on the available scientific evidence was published on the Club’s website in 2016, followed by an article on the FRDC’s stakeholder consultations in Canberra in 2018, and a further article examining the issues papers and scientific research on the NCCP website in 2019.

(c) Delays and criticism of the NCCP

The FRDC was expected to submit the NCCP in 2018, but this was delayed to late 2019 to allow more time to complete its research. Further delays occurred when the CSIRO’s resources at the Australian Centre for Disease Preparedness got diverted during the COVID-19 pandemic.

In the meantime, the research papers and updates previously available on the NCCP website were quietly removed (however, this content appears to be back online on the FRDC's Carp News webpage) and public engagement ended abruptly. Many stakeholders and scientists began to criticise the NCCP for its lack of transparency.

In addition, overseas scientists criticised the NCCP, arguing that even if the plan reduced 95% of the carp population, carp’s genetic resistance to CyHV3 will allow their numbers to quickly recover. Some overseas scientists argued that the Australian Government should instead focus on improving the health of our waterways, such as reducing the amount of water extracted for thirsty crops such as cotton and restoring aquatic habitats for native species.

The NCCP was finally presented to the Department of Agriculture, Fisheries and Forestry on 30 September 2022 and released to the public on 3 November 2022. The evidence base underpinning the NCCP reflects the issues papers and scientific research publicly available on the NCCP prior to 2020, and addresses some of the criticism by overseas scientists.

The NCCP examined the effectiveness of CyHV3 as a biocontrol, the risks associated with releasing CyHV3 and how those risks can be managed, how the release of CyHV3 can be managed, and recommendations on further research required before the NCCP can be implemented.

3. The effectiveness of CyHV3 as a biocontrol (return to contents)

The NCCP’s findings on the effectiveness of CyHV3 as a biocontrol reflects much of the issues papers and scientific research that was previously available on the NCCP website prior to 2020. By then, it became clear that self-propagating transmissions of CyHV3 resulting in a ‘Carpageddon’ was unlikely.

CyHV3 requires suitable water temperatures for virus transmission and outbreak of disease (within a range of 16°C to 28°C but ideally 21°C to 25°C) and suitable carp densities to allow physical contact between infected carp and uninfected carp to allow transmission of the virus. Those conditions can be found in spring to early summer when carp are spawning.

This means the ‘set and forget’ approach for releasing the Myxoma Virus and later the Calicivirus to control rabbits in Australia will not succeed with CyHV3. To be effective, the release of the virus will need to be carefully planned, actively managed, and released on an ongoing basis whenever ideal conditions present themselves.

Whether coastal waterways with saline conditions (such as such as the Gippsland Lakes (Victoria), Albert and Logan Rivers (Queensland), and the Lower Lakes (South Australia)) reduces or eliminates the virus’s capacity to infect or kill carp is still unknown.

(a) Potential for genetic resistance to CyHV3

Some overseas scientist expressed concerns that carp’s genetic resistance to CyHV3 will allow populations to quickly recover following the release of the virus. However, the NCCP reported preliminary research found no evidence Australian carp possess the gene variants that provides genetic resistance. The NCCP conceded this was based on ‘exploratory’ work only and not a comprehensive survey of Australian carp genetics.

Nevertheless, this claim may be plausible. CyHV3 did not emerge until the 1990s and Australia’s carp population can be traced back to carp introduced into Prospect Reservoir in 1907 and 1908 (including the Boolarra Strain). Consequently, it is possible Australia’s carp population has not acquired genetic resistance to CyHV3 due to 114 years of isolation from the world carp population.

The NCCP noted that carp-goldfish hybrids were less susceptible to the virus and it was unclear what role these hybrids would play in building resistance in carp populations to CyHV3.

(b) Reductions of 40% to 60% expected

Carp Out 2016 Fishing

The release of CyHV3 into our waterways won't bring an end to popular 'carp-buster' fishing comps like the Canberra Carp-Out. The carp virus is expected to reduce carp numbers by 40% - 60% over ten years. With an estimated 372 tonnes of carp in Lake Burley Griffin, that still leaves 149 to 223 tonnes of carp after the virus has been deployed.

Potentially, CyHV3 may be effective against Australian carp for up to ten years, with adult carp falling victim to the virus in the initial outbreak, followed by regular kills of juvenile carp in the following years. The virus is expected to reduce 40%-60% of the carp population, with 60%-80% reductions possible in less resilient populations.

(c) Latency and recrudescence

Not all carp infected with CyHV3 during the initial deployment will become diseased and die. The virus will remain dormant (known as a ‘latent infection’) in some fish until conditions trigger the outbreak of disease (known as ‘recrudescence’).

The extent to which the CyHV3 deployment will successfully reduce and supress carp numbers after the initial deployment depends on the ability of the virus in latently infected carp to continue infecting other carp and eventually triggering recrudescence in the host carp.

Figure 1 depicts modelled release of CyHV3 into the mid-Murray River in 2000, assuming that latently infected carp continue to infect other carp and succumb to recrudescence. The shaded grey area represents carp populations in the absence of virus release.

Figure X Modelled release of the carp virus into the mid Murray River in 2000

Figure 1: Modelled release of the carp virus into the mid-Murray River in 2000, assuming recrudescence and reasonable transmission. The shaded grey area represents carp populations in the absence of virus release (National Carp Control Plan).

This ought to bring carp densities below 100 kg/ha in our waterways. While this will not amount to complete eradication of carp, it will alleviate the negative impacts of carp on waterways.

According to the NCCP, an overseas literature review of the impacts of carp as an invasive species identified carp densities of 50 kg/ha will impact other fish species, 100 kg/ha will impact aquatic plants, and 150 kg/ha will have negative impacts on water clarity.

The NCCP reported that the estimated eastern Australia’s carp biomass in 2018 was approximately 205,000 tonnes. Carp densities of 200 – 400 kg/ha were recorded in Australia's southern river systems. The highest densities were recorded in lower system wetlands in the Murray, Murrumbidgee and Lachlan catchments (see carp density heat map at figure 2). 

Carp surveys carried out by the ACT Government of Canberra's urban lakes estimated a biomass of 372 tonnes of Carp in Lake Burley Griffin, which equates to 560 kg/ha . The survey also recorded carp densities of 380 kg/ha and 588 kg/ha Upper Stranger Pond and Isabella Pond respectively prior to those ponds being drained in April 2017.

Figure X Carp densities 2018

Figure 2: Heat map showing Carp densities in 2018 (Todd, C.R., Koehn, J.D., Brown, T.R. Fanson, B., Brooks, S., and Stuart, I. (2019). Modelling Carp Biomass: Estimates for the Year 2023. Arthur Rylah Institute for Environmental Research, Department of Environment, Land, Water and Planning, Heidelberg, Victoria).

More detailed maps showing carp densities were prepared for case studies for the Murray and Murrumbidgee rivers and Lachlan rivers as of 2019. A copy of the biomass for the Murry and Murrumbidgee rivers is at figure 3.

Figure X Murray Murrumbidgee Case Study Biomass

Figure 3: Murray-Murrumbidgee Case Study Biomass (Mathers. K, McKinlay. G, The Wedge Group, 2018, National Carp Control Plan; High Biomass Clean-up Options, Planning and Execution Workshop, Workshop Outcomes Report).

Population modelling used to estimate carp biomass indicates it will fluctuate in response to climatic drivers, and that Australia’s carp biomass has the potential to reach just over 1 million tonnes in a worst case scenario involving three consecutive years of flooding (see predicted carp density heat maps for drought and flood conditions in 2023 at figure 4)). Noting that Australia is currently experiencing its third consecutive La Niña season, one would expect carp densities are considerably higher in comparison to 2018.

Figure X Modelled carp densities Drought 2023Figure X Modelled carp densities Flood 2023

Figure 4: Heat map showing predicted Carp densities based on modelling for both drought and flood conditions in 2023 (Todd, C.R., Koehn, J.D., Brown, T.R. Fanson, B., Brooks, S., and Stuart, I. (2019). Modelling Carp Biomass: Estimates for the Year 2023. Arthur Rylah Institute for Environmental Research, Department of Environment, Land, Water and Planning, Heidelberg, Victoria).

(d) Complementary measures

CyHV3 will not work as a stand-alone measure and will need to be implemented in conjunction with other measures. The NCCP recommends targeted harvesting in sections of waterways with high carp densities prior to releasing the virus.

It also discussed the potential of the Trojan Y Chromosome as a complementary measure. Trojan Y Chromosome technology is a genetic bio-control method that skews the carp population towards male carp, resulting in population decreases due to the reduction of female carp.

However, the NCCP noted there were biological and logistical challenges to be addressed before the Trojan Y Chromosome becomes a viable means of carp control.

(e) Further research about the effectiveness of the virus recommended

The NCCP recommends further research and modelling is needed to better understand how recrudescence is triggered in latently infected carp, as the research it carried out was limited to short term studies of juvenile carp in laboratory settings.

Other recommendations included further investigation on whether Australian carp to possess the gene variants required to confer genetic resistance to the virus, the role carp-goldfish hybrids could play in building resistance, and the effectiveness of the virus in saline conditions.

4. Risks associated with releasing CyHV3 (return to contents)

The NCCP examined risks to humans and animals other than carp, environmental risks, and water quality.

(a) Risk of infection of species other than carp

Yellowbelly Connor Davis 1.91 kg

Connor Davis with a nice healthy Yellow Belly at the 2013 ANSA Burrinjuck Convention. Testing of native species and rainbow trout found none of the fish tested were infected or affected by CyHV3. Nevertheless, the NCCP recommends further testing be carried out due to high level of public concern about the risks CyHV3 may pose to species other than carp.

In terms of risks to humans, other animals, and fish other than carp, the science is settled that that CyHV3 is specific to European carp (Cyrpinus carpio) and Koi carp (Cyprinus rubrofiscus). CyHV3 is not an infectious animal disease that can be transmitted to humans (or "zoonosis") and there are no cases of infection of humans who handled diseased fish.

In addition, the European Commission (European Commission, Health and Consumer Protection Directorate-General, Scientific Committee on Animal Health and Welfare, 2000. Assessment of zoonotic risk from Infectious Salmon Anaemia virus) has found no evidence for any fish virus causing disease in humans.

Some international research indicates that CyHV3 may infect other fish species but without affecting them or causing disease. Disease caused by CyHV3 has only been recorded in European carp and hybrids of European carp.

Testing done by the CSIRO prior to the NCCP found none of the 22 non-target species tested were either infected or affected by the virus.

However, those familiar with the initial experiments will be aware that problems were encountered during experiments on Murray cod, silver perch and rainbow trout.

The NCCP reports that further testing showed no evidence of CyHV3 infections in Murray cod and silver perch but testing on rainbow trout encountered problems before they could be exposed to CyHV3.

Notwithstanding the current state of scientific evidence, the NCCP noted the high level of public concern about the risks CyHV3 may pose to species other than carp. Accordingly, it recommended further testing (including further testing on rainbow trout) to allay those concerns.

(b) Environmental and water quality risks

Blue green algae

The risks identified by the NCCP due to mass carp mortalities following a virus-induced carp kill were depleted oxygen levels, toxic algal blooms bacteria and botulism outbreaks, and impacts on drinking water.

The NCCP contains no surprises regarding the environmental and water quality risks posed by decomposing carp on water quality. The Plan reflects the research findings previously available on the NCCP website prior to 2020.

Those risks are depletion of dissolved oxygen in the water, toxic algal blooms, bacteria and botulism outbreaks, and impacts on drinking water. The NCCP found that those risks are unlikely to occur in flowing waterways where carp densities are below 300 kg/ha. Those conditions are found in most of the regulated rivers in the Southern Murray Darling Basin.

The risks of depleted oxygen and toxic algal blooms can arise in still or slower moving water bodies and where carp densities exceeding 300 kg/ha, for example, wetlands, lakes, reservoirs, and unregulated rivers that cease to flow during dry periods. Such conditions can be found in the Northern Murray Darling Basin. Carp surveys of Canberra's local lakes reported carp densities of 380 kg/ha to 588 kg/ha.

The NCCCP reports that outbreaks of harmful bacteria and botulism may occur due to poor water quality. However, there have been no bacteria outbreaks and only one recorded botulism outbreak as a result of a fish kill. The risks can be addressed by avoiding depletion of oxygen and algal blooms during fish kills.

The NCCP found that standard water treatment and disinfection processes for drinking water will be sufficient to address water quality issues posed by most fish kill scenarios, and that additional activated powdered carbon can be used where carp are concentrated at higher densities provided it does not exceed 2000 kg/ha.

Even under flood conditions, the carp density heat maps at figure 4 indicates few waterways are likely to have carp densities of such magnitude. However, the NCCP reports that such densities could potentially occur if dead carp accumulate in small areas as a result of water currents or wind.

The NCCP proposes targeted harvesting of carp prior to the release of the virus in waterways with high densities of carp, and carcass management strategies to address those environmental and water quality issues.

One issue the NCCP was unable to address was how and where accumulated nutrients from decomposed carp would get trapped in river and lake sediments and the potential for those nutrients to contribute to future toxic algal blooms.

5. Implementing the National Carp Control Plan (return to contents)

The NCCP’s implementation strategy sets out to reduce and suppress carp populations over a five to ten year period and manage the environmental and water quality risks associated with large-scale carp deaths.

Because carp inhabit a vast area of the continent over a diverse range of ecosystem types (from tidal subtropical upper estuaries to temperate, highly regulated dryland rivers), the implementation strategy cannot plan for every circumstance each region or locality.

Accordingly, it provides national guidelines on which detailed plans can be tailored to meet the challenges and risks presented by each region or location.

The implementation strategy sets out a ten-year time frame with the following phases:

Phase 1. Planning

The first one to two years involves detailed implementation planning at regional and local levels to identify how best to release the virus, what resources will be required, and how to manage risks at each region or location.

This phase also includes obtaining the necessary legislative approvals under Commonwealth and State/Territory legislation.

Phase 2. Initial deployment of the virus

The second phase is expected to take two to three years and will be coordinated nationally by the Commonwealth and delivered by each State and Territory government.

This phase will involve establishing implementation teams for each region or locality, intense harvesting of carp in areas of high carp densities prior to the release of infected carp, preparation and release of virus-infected carp, and carcass management following fish kills.

The virus is expected kill adult carp during this phase and reduce carp populations by 40% - 60%.

The NCCP proposes deploying the virus in the Murray Darling Basin in the first year, and then in the highland and coastal regions in the second to third year (including the Swan and Canning Rivers in Western Australia).

Given carp biomass fluctuates in response to flood or drought conditions, the timing of initial virus deployment needs to be carefully planned to ensure the quantity and concentration of dead Carp do not lead to unmanageable environmental and water quality risks.

The NCCP recommends the initial deployment occurs under moderate flow conditions (i.e. neither flooding with full wetland inundation, nor drought), and when climatic conditions in the years preceding release have produced relatively low carp populations.

Carp photo dead carp

Managing the environmental and water quality risks associated with mass carp mortalities due to CyHV3 presents as one of the biggest challenges under the NCCP. A full clean up of dead carp is not feasible but the NCCP argues that other strategies can be applied to prevent or reduce environmental and water quality risks following a fish kill.

The NCCP talks about 'carcass management', because a full-scale clean-up is not on the cards. The aim of 'carcass management' is to ensure dead carp do not pose risks to water quality, ecologically sensitive areas, social amenity (such as tourism and recreation), and infrastructure.

The NCCP has identified a range of carcass management strategies grouped into four broad categories:

  • herding live uninfected carp through manipulation of water flows or water levels prior to the release of the CyHV3 virus so that they school in low risk locations
  • herding infected live carp away from sections of waterway more prone to water quality impacts and into lower risk locations
  • regulating the flow of water to transport dead carp and nutrients away from sensitive areas to lower risk locations or locations where carcasses can be intercepted and removed, and
  • physical removal of the carcasses from waterways.

A complete clean-up is only planned if there are risks to social amenity or to ecologically sensitive waterways.

The NCCP states that genetic biocontrol technologies to control carp are not yet feasible. Two such genetic biocontrol measures are the Daughterless Carp Gene and the Trojan Y Chromosome. Both measures have the potential to create male-only carp populations.

However, such measures may take up to 50 years to implement given carp live up to 30 years and produce up to 3 million eggs each year. In addition, the Daughterless Carp Gene involves Genetically Modified Organisms which may present other environmental risks.

The NCCP does not mention Daughterless Carp technology, and advises that substantial investment in research and infrastructure (hatcheries) over approximately ten years is needed before Trojan Y Chromosome technology can be deployed.

Phase 3. Post-deployment

The third phase is expected to take five to seven years. This phase assumes latently infected carp will continue transmitting the virus to other carp before succumbing to recrudescence (when the virus triggers the disease in the host fish after a period of latency).

During this time, the number of carp kills is expected to decrease and likely to comprise of juvenile carp, presenting reduced water-quality risks.

It is expected the need for national coordination and the size of the implementation teams will decrease over that time and operational responsibility will gradually handed over to the States and Territories.

Phase 4. Completion

This marks the cessation of national coordination of carp control measures and complete handover of responsibilities to the States and Territories.

6. Cost of implementation (return to contents)

The NCCP was unable to provide a total cost required to implement the Plan. However, it estimated the cost of implementing Phase 2 in the Murray and Murrumbidgee systems at $190 million in 2019 dollars.

The NCCP estimates the Murray and Murrumbidgee systems accounts for 30% of Australia’s carp population. Accordingly, using a ‘back of the envelope’ calculation, the total cost of implementing Phase 2 could reach in excess of $633 million in 2019 dollars, or $705 million in today’s dollars.

While this may sound like a large sum of money, Phase 2 will be implemented over three years. Even if the cost is rounded up to $1.2 billion over three years, then this equates to 0.069% each year of Australia’s forecast tax and other revenue for 2022-23.

This does not include the cost of intense harvesting of carp in areas of high carp densities prior to the release of infected carp. That figure also does not take into account all the complementary measures that will be needed to ensure successful suppression of carp such as habitat restoration, restocking of native fish, other bio-control measures such as R&D and implementation of Trojan Y Chromosome.

7. Overseas developments (return to contents)

Before concluding, it is worth pausing to look at what is happening overseas in the past few years. There have been media reports of carp kills due to outbreaks of CyHV3 in the United States. In addition, it appears that CyHV3 outbreaks have reduced and suppressed carp numbers in the Mississippi River.

It is interesting to note that the majority, if not all, of the fish killed in those outbreaks were carp. Some media reports did mention insignificant numbers of other species found dead and there was one report of bluegill covered in parasites following one CyHV3 outbreak.

The University of Minnesota Aquatic Invasive Species Research Center is also looking at how CyHV3 can be used to control carp populations in Lake Minnesota. It is also exploring other potential carp control methods including the Carp Edema Virus Disease (also known as Sleepy Koi Disease) and corn-based bait containing fish toxins.

8. Conclusion (return to contents)

The NCCP has confirmed the potential of CyHV3 to control Australia’s carp population on a continental scale. The scientific evidence forming the basis of the plan delivers few surprises as it reflects the issues papers and scientific research previously available the NCCP website until 2020.

The NCCP reports that preliminary research indicates Australian carp may not possess the gene variants overseas carp to genetic resistance to CyHV3. Accordingly, the virus is expected to reduce and suppress carp populations in Australia over a ten year period.

The virus is expected to kill adult carp during the initial outbreaks in the first two years. Afterwards, the number of carp kills is expected to decrease, and mainly affect juvenile carp.

Carpageddon is unlikely to be realised and reductions of 40%-60% are expected instead. Less resilient populations may see a 60%-80% reduction.

These forecasts assume that latently infected but otherwise healthy carp will continue to transmit the virus to other carp, and that the virus will trigger further outbreaks of disease.

The virus does not pose any health risks to humans and mammals, and further research continues to show other fish species are not affected by the virus.

The NCCP noted the public expressed a high level of concern about the virus infecting other fish species. Accordingly, the NCCP recommended further research take place to allay those concerns.

The NCCP reported that carp kills resulting from the deployment of the virus presents environmental and water quality risks. Those risks are depleted oxygen levels in the water, toxic algal blooms, bacteria and botulism outbreaks, and impacts on drinking water.

The NCCP found that those risks are unlikely to occur in flowing waterways where carp densities are below 300 kg/ha. Those conditions are found in most of the regulated rivers in the Southern Murray Darling Basin. The NCCP found that risks associated with treatment and disinfection processes for drinking water are manageable provided carp densities do not exceed 2000 kg/ha.

The NCCP outlines strategies for managing environmental and water quality risks where carp densities exceed 300 kg/ha and for slower or still moving waterways. These include not releasing the virus during drought or flood conditions, harvesting of carp prior to virus release to reduce carp densities to more manageable levels, and ‘carcass management’. A full clean-up will only occur under limited circumstances.

Further research is required before any recommendation to proceed with the NCCP can be made. It was not possible to list all additional research recommended by the NCCP. But some key research recommendations include:

  • further research and modelling to better understand how the disease is triggered in latently infected but otherwise healthy carp;
  • whether Australian carp to possess the gene variants required to confer genetic resistance to the virus;
  • the role carp goldfish hybrids may play in developing carp’s resistance to the virus;
  • the effectiveness of the virus under saline water conditions; and
  • further testing to address the public’s concerns about the potential for CyHV3 to infect other species of fish.

It is too early to fully cost the implementation of the NCCP. However, the cost of the initial deployment of the virus in the Murray and Murrumbidgee systems was estimated to be $190 million over two to three years in 2019 dollars.

Given this region accounts for 30% of Australia’s carp population, a back of the envelope calculation indicates the total cost of initial deployment could reach in excess of $633 million in 2019 dollars, or $705 million in today’s dollars.

While this may sound big, it should be viewed as an investment in revitalizing regional Australia. Even if this figure is rounded up to $1.2 billion over three years, then the cost each year only equates to 0.069% Australia’s forecast tax and other revenue for 2022-23.

Senator the Hon Murray Watt, Minister for Agriculture, Fisheries and Forestry, recently wrote to the NSW Council of Freshwater Anglers Inc indicating that the further research, as well as seeking agreement from all levels of government, legislative approvals and conducting stakeholder consultations is expected to take several years. 

Should the governments agree to proceed with the NCCP, the implementation strategy recommends detailed planning to take place two years prior to the initial deployment of CyHV3. Accordingly, it may be a decade before the virus is finally released.

In the meantime, there are other steps governments and the community can take to address the damage caused by carp and improve the health of Australia's inland waterways. These include:

  • habitat restoration of aquatic ecosystems;
  • restocking native fish;
  • improving water quality; and
  • addressing unsustainable harvesting of water from the Murray-Darling Basin.

These are not new ideas and were raised as far back in 1962 in the Report of the State Development Committee of the Victorian Parliament on the introduction of European carp into Victorian waters.

Should our governments decide to proceed with the NCCP, this will be one of the biggest things to happen to our environment in many generations. Therefore, it is important the recreational fishing community takes the time to understand what is in the plan and the opportunities and risks it presents.

Accordingly, anglers are encouraged to download a copy of the plan and read it carefully. Links to the plan, previous Canberra Fisherman's Club articles on the carp virus, and other information can be found below.

9. Further reading

National Carp Control Plan and related documents

Other Canberra Fisherman's Club articles on the carp virus

Other reading

BJ.2019.013

 About the author: Anthony Heiser is a member of the Canberra Fisherman’s Club (since 2007 including 11 years on the Committee) and a committee member of the Recreational Fishing Alliance of New South Wales since 2019. He previously served as Secretary of the Capital Region Fishing Alliance 2013 to 2020. He has kept a keen eye on the latest developments of the National Carp Control Plan since its announcement in 2016, and participated in the National Carp Control Plan stakeholder workshop, Canberra, on 19 February 2018. Anthony is also a member of the Coffs Coast Fly Fishing Club since moving to the Mid North Coast in 2021.

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