The release and spread of freshwater fish outside their natural range (freshwater fish incursion) is a significant issue in Australia and a major biosecurity risk to freshwater ecosystems. Currently 44 non-native freshwater fish species have been recorded in Australian freshwaters, with a further 76 native freshwater fish species found outside their natural range. Historically many of these fish were primarily introduced for recreational benefits by acclimatisation groups. More recently, ornamental and aquarium fish have been released into freshwater systems, either deliberately or accidentally. When fish are introduced into an area where they don’t naturally occur, they can pose a threat to native fish populations by predation, competition for food, shelter and breeding resources, as well as contributing to habitat degradation. These processes can have various environmental, social and economic impacts.

Preventing the release of non-native freshwater fish into the natural environment, through quarantine, legislation and education, is the most cost-effective management approach. Once an incursion has occurred, a rapid and early response is needed to maximise the chances of eradication. If a species has spread within the environment, other options such as containment and control may need to be considered. These can be costly and vary in their success. Effective responses to freshwater fish incursions in Australia have been inhibited by the lack of a consistent nationally-applicable arrangements and procedures that can be implemented quickly when such situations arise. In recognition of this, the Invasive Animals Cooperative Research Centre (IA CRC) funded a project to clarify how to progress the establishment of national emergency response arrangements for freshwater fish incursions in Australia. The project included representatives from all relevant State and Territory government agencies involved in managing freshwater fish incursions.

A key task of this project was reviewing current management of freshwater fish incursions, including:

• documenting national and international approaches to the management of freshwater fish incursions
• reviewing surveillance, eradication and control programs in Australia
• reviewing international freshwater fish containment methods

Included in the many recommendations made by the project was the need to link into existing national biosecurity governance and processes, and learn from other biosecurity sectors in Australia.

For more information contact: renae.ayres@dse.vic.gov.au or pam.clunie@dse.vic.gov.au

The following publications are available on the IA CRC PestSmart Toolkit website:

Ayres, R. and Clunie, P. (2010) Management of freshwater fish incursions. Invasive Animals Cooperative Research Centre, Canberra

Ayres, R. and Clunie, P. (2010) Towards a national emergency response system for freshwater fish incursions. Invasive Animals Cooperative Research Centre, Canberra

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Rabbits have long been recognised as a major pest in Australia severely degrading both agricultural land and conservation areas Biosecurity Strategy for Victoria – implementation plan 2010 to 2013. A large collaborative five year research project involving DEPI, Department of Primary Industries, Melbourne Water, Port Phillip and Western Port Catchment Management Authority, Parks Victoria, Victorian National Parks Association, Greening Australia, and VicTrack is investigating the most cost effective techniques for restoring a degraded, rabbit infested landscape. The study area is 280 ha of an 781 ha farm in the upper Werribee River catchment, west of Melbourne. The cost effectiveness of four techniques for controlling rabbits is being evaluated: warren impact (ripping with heavy machinery versus implosion versus fumigation) and landscape baiting with 1080.

Scientists from ARI, CSIRO, Kingfisher Research and Agricultural Technical Services are monitoring the success of revegetation works aimed at landscape restoration, with and without rabbit control. Across the property 6,000 seedlings of three indigenous tree species, Drooping Sheoak (Allocasuarina verticillata), Golden Wattle (Acacia pycnantha) and Manna Gum (Eucalyptus viminalis) were planted either with or without tree guards. Ten, one hectare plots were selected, half with rabbit control and half without. Survival and growth rates of unprotected and protected seedlings are being monitored in 30 sub-plots within the one hectare plots.

Guarding trees significantly increased their survival, regardless of whether or not rabbits had been controlled: over 90% of protected seedlings survived. Unguarded trees fared better in areas where rabbits had been reduced with 35% of seedlings surviving. In areas where rabbits hadn’t been controlled, less than 10% of unprotected tree seedlings persisted. Some of the gum trees have grown 3m in the first year thanks to the good rainfall. On-going monitoring will reveal if these trends continue over the next few years, and how they relate to the rabbit population dynamics being tracked by the project team. For land managers, this will mean better advice about the most cost effective method of rabbit control and landscape restoration.

For more information contact: Ivor Stuart at research.ari@dse.vic.gov.au

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Feral cats are widely distributed across mainland Australia and many offshore islands where they maintain self-sustaining populations without any intentional assistance from humans. Feral cats are implicated in the decline of populations of native species through direct predation, competition for resources and the spread of disease. There are currently no cost-effective techniques that can be used to manage feral cat populations over large areas in Australia. Existing techniques such as shooting or trapping require significant investment in skilled labour and as such can only achieve population reductions in relatively small areas. Poison baits intended for feral cats need to be surface-laid and this can present a significant hazard to wildlife that must be carefully addressed.

A collaborative research group is developing a bait and toxicant delivery system that will offer a humane and highly target-specific technique for managing populations of feral cats over large areas. It is intended to restrict the use of this bait to areas of land managed for conservation such as National Parks. The project has pioneered the development of a new toxicant formulation using para-aminopropiophenone (PAPP). A hard-shelled pellet delivery system achieves improved specificity by exploiting physiological and behavioural differences between feral cats and native wildlife species.

Four field trials have been undertaken to collect data as part of the process for registration of Curiosity® bait as an agricultural chemical. The first field trial was conducted in French Island National Park, Victoria, with subsequent trials conducted at Dirk Hartog Island (Western Australia), Christmas Island National Park (Indian Ocean) and Tasman Island (Tasmania). Results to date indicate that the Curiosity® bait will provide park managers with a useful technique for controlling feral cat populations. Further field trials will be undertaken at mainland sites which are considered ‘more complex’ due to the greater range of native and exotic species present. Project collaborators include Commonwealth, Western Australian and Victorian government conservation agencies along with Scientec Research Pty Ltd.

For more information contact: michael.johnston@dse.vic.gov.au

The following reports and articles are available. Accessible versions of these reports are available on request by emailing research.ari@dse.vic.gov.au:

ARI Technical Report 234 - Field assessment of the Curiosity^® bait for management of feral cats in the semi-arid zone (Flinders Ranges National Park) [PDF File - 1.5 MB]
ARI Technical Report 234 - Field assessment of the Curiosity^® bait for management of feral cats in the semi-arid zone (Flinders Ranges National Park) (accessible version) [MS Word Document - 5.0 MB]
ARI Technical Report 205 - Bait efficacy trial for the management of feral cats on Dirk Hartog Island [PDF File - 2.2 MB]
ARI Technical Report 200 - Bait efficacy trial for the management of feral cats on Christmas Island [PDF File - 1.2 MB]
Field assessment of the Curiosity^® bait for management of Feral Cats after fire at Wilsons Promontory National Park [PDF File - 1.7 MB]
Field assessment of the Curiosity^® bait for management of Feral Cats after fire at Wilsons Promontory National Park (accessible version) [RTF File - 265.6 KB] 

Johnston, M.J., Shaw, M.J., Robley, A and Schedvin, N.K. (2007) Bait uptake by feral cats on French Island, Victoria. Australian Mammalogy 29(1):77-84

Marks, C.A., Johnston, M.J., Fisher, P.M., Pontin, K. and Shaw, M.J. (2006) Differential particle size ingestion: Promoting target-specific baiting of feral cats. Journal of Wildlife Management 70(4): 1119-1124

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Eastern Gambusia, Gambusia holbrooki, were introduced to Australia from the USA in 1925 for the purpose of mosquito control. The species spread quickly and populations are now established in freshwater systems in every state and territory. Whilst it is now apparent that they are rather ineffective as a mosquito control agent, the species has been implicated in the decline of at least nine native fish species and ten frog species in Australia. Eastern Gambusia are aggressive towards other aquatic fauna, are able to reproduce quickly, and can tolerate a broad range of environmental conditions. These characteristics have contributed to their ability to out-compete native species.

Despite this knowledge, there is very little information on the size at which Eastern Gambusia populations start having a detrimental impact on native fish populations. This information would allow an understanding of the levels of Eastern Gambusia control required to result in a significant improvement to the native fish community. To address this, scientists from ARI are conducting research within the billabong systems of the Murray-Darling Basin to determine: (a) what influence Eastern Gambusia have on wetland native fish communities, (b) the level of Eastern Gambusia reduction needed to result in a significant improvement to native fish communities; and (c), the cost of reducing Eastern Gambusia populations to those levels that will benefit native fish (cost-benefit analysis).

Over seventy billabongs have been surveyed for native fish and Eastern Gambusia. Results show that some native species were in low abundance where there were high numbers of Eastern Gambusia, whilst other native species appeared to be unaffected. Different trends among native species are likely to be due to differences in species-specific habitat preferences, vulnerability of eggs to predation, and access to shelter. To test these survey results further we are removing varying numbers of Eastern Gambusia and monitoring the response of native species. The cost-effectiveness of this control method will be determined by comparing labour and equipment costs with benefits to native fish. The steps used to carry out this study will provide a template for evaluating the relative cost-benefit of controlling other invasive fish species.

This project is funded by the Murray-Darling Basin Authority.

For more information contact: zeb.tonkin@dse.vic.gov.au

The following fact sheets are available:

Gambusia fact sheet 2011 [PDF File - 1.1 MB]
Gambusia fact sheet 2011 (accessible version) [MS Word Document - 1.2 MB]
Gambusia removal guidelines 2011 [PDF File - 4.1 MB]
Gambusia removal guidelines 2011 (accessible version) [MS Word Document - 4.8 MB]

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Wild dogs (which include Dingoes, feral dogs and their hybrids) are declared pests in most states of Australia. Global Positioning System (GPS) technology has been used to track the movement patterns and interactions of wild dogs in forests in south-east New South Wales, north-east Victoria and Gippsland. This study is being run in partnership with State Forests NSW, the Australian Hydatid Control and Epidemiology Program, the Victorian Department of Primary Industries and DEPI.

Thirty-five wild dogs have been fitted with collars containing a GPS unit and conventional VHF transmitter programmed to collect data at regular intervals throughout the night and day. This information is sent to researchers via the Argos satellite network. Transmitter data indicates that wild dogs stay within their territories, and in general don’t make a special effort to travel long distances to reach agricultural enterprises such as sheep grazing. This dispels the assumption that wild dogs target these areas It appears that wild dogs have at least two distinct behavioural modes, 1) encamped; where they move over relatively short distances and make many sharp turns, and 2) exploratory; where movements are longer in distance and more direct. Territories of the wild dogs tracked ranged from 10 km² to over 150 km². A small number of individuals have been tracked moving hundreds of kilometres, most likely in search of a new territory.

Mathematical models are currently being used to try to identify how certain landscape features influence habitat use and movement by wild dogs. This will improve the capacity of land managers to limit the impact of wild dogs on agricultural communities, and increase our understanding of their role in the ecosystem. The GPS method of tracking has the potential to provide information on a range of aspects of wild dog ecology in a short period of time and is relatively cost-effective compared to the alternative method of ground based radio-tracking.

For more information contact: alan.robley@dse.vic.gov.au

The following article outlines some of the issues related to wild dog and fox populations in Australia:

Fleming, P., Allen, L., Lapidge, S., Robley, A., Saunders, G., and Thomson, P. (2006) A strategic approach to mitigating the impacts of wild canids: proposed activities of the Invasive Animals Cooperative Research Centre. Australian Journal of Experimental Agriculture 46: 753-776.

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