Sessional Committee on Environment and Sustainable Development Written Submissions Received Volume 2 Issues associated with the progressive entry into the Northern Territory of Cane Toads October 2003
Tabled Paper 1123
Tabled Papers for 9th Assembly 2001 - 2005; Tabled papers for 9th Assembly 2001 - 2005; Tabled Papers; ParliamentNT
Tabled by Delia Lawrie
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Written Submissions Dr Freeland Volume 2 Cane Toad Inquiry Report 161 INVESTIGATING CANE TOAD CONTROL Other than some minor works needed for investigating the practicality of cane toad proof fences, the only serious proposal for control of cane toad populations is the possibility of developing biological control. I have previously listed the criteria against which any proposed agent should be measured. I am not qualified to comment on the molecular biology involved in the current research. There is however a need for better public understanding of what is involved in this research: the risks and the nature of the specific triggers for the work to cease or be continued. The following issues may be of assistance in developing a more structured understanding of what will need to be involved. 1. Given that the attempted immunological disruption of cane toad metamorphosis has not as yet been successful, how much work (time and resources) is required before it is know whether it is possible? 2. The work should cease if the compound causing disruption of cane toad metamorphosis has the same impact on native species. 3. If a virus specific to cane toads is to be used as a carrier then it will need to be demonstrated that it is species-specific in its host selection. 4. How common are species of virus that are host specific to individual amphibian species? Or do they tend to infect an array of amphibian and fish species? 5. If a virus that is not host-specific is to be used as a carrier (i.e. a possibly effective way of maintaining the modified virus in nature after it has removed all or many cane toad larvae/ metamorphlings), its potential for survival in nature will be related to competition with the normal wild virus. To assess potential for success prior to release it is critical to: have a sound understanding of virus's natural temporal/spatial patterns of prevalence, transmission and impacts in nature now (this determines whether a particular carrier virus is in fact worth the effort of the genetic engineering (if rare, episodic or pathological, survival of the modified virus is problematic). determine the competitive interactions between the normal wild virus and its genetically modified relative (i.e. relative rates of replication and persistence in hosts. competition between the viral strains in hosts; and relative rates of transmission among hosts). 6. Augmentation of the temporal and spatial occurrence of the virus through man assisted dispersal of the modified virus should not occur unless it can be demonstrated that the virus's normal, pathological effects to frogs and fish are inconsequential. 7. The stability of the genetic modification will need to be well demonstrated. Only CSIRO can provide information on how they plan to deal with these issues. The biological control effort will require a massive amount of work and great expense, may have a high probability of failure due to epidemiology constraints and may pose profound dangers to native frog and fish communities unless the issues are dealt with effectively.