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Collection, euthanasia and disposal of the cane toad, Rhinella marina

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Ratification Date: 09 Dec 2016

Position statement

This statement outlines circumstances in which it is appropriate to humanely kill cane toads, Rhinella marina (previously Bufo marinus), and acceptable methods that should be used.

The eradication of cane toads from Australia is not currently feasible and large scale collection of cane toads has little impact on population numbers. However it is recognised that localised cane toad collection and euthanasia is sometimes required.

The method chosen to kill cane toads should be the most humane available. Cane toads collected by the general public should, wherever possible, be euthanased humanely by a veterinarian or trained operator. Research into humane, practical and cost-effective means of euthanasia is required.

The AVA supports the ongoing introduction of innovative methods to protect wildlife from cane toads.

Background

Cane toads were introduced into Queensland in the 1930s to control pests in sugar cane. The toads were released before the implications of their introduction were understood and have since spread to New South Wales, the Northern Territory and Western Australia.1

The environmental damage caused by cane toads and the potentially harmful nature of this introduced pest species is well recognised in Australia. The impacts of the cane toad are listed as a key threatening process under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).

Live and deceased cane toads represent a threat to companion animals and native predators (e.g. snakes, lizards/monitors, quolls) that ingest their toxin. When an area is first invaded by cane toads, naturally high levels of invertebrates appear to support large toad numbers. As food items are exhausted, toad levels appear to decline. Decline in invertebrate prey that follows toad invasion probably affects other insectivorous predators and may interrupt ecological processes, at least temporarily.2

Methods to minimise cane toad impacts on a local scale include:

  • Removing eggs from frog ponds.
  • Constructing fences (at least 50cm high) to protect native fish and frog ponds.

It is important for the fencing to restrict cane toad access, but not native species (frogs, reptiles, mammals, etc)

Collection

Toad collecting is not encouraged as it is not effective in reducing numbers, nor impacts, of cane toads and misidentification can result in the killing of protected native amphibians (species other than cane toads) by untrained people. Further information is available in Taylor and Edwards (2005).3

However it is recognised that the public need to remove cane toads from back yards, ponds and other small-scale local areas to protect pets and native species.

Euthanasia

Increasingly, veterinarians, environmental organisations and government stakeholders are asked to comment on the most humane method of killing cane toads.

Guidelines

Wherever possible, toads should be anaesthetised by a veterinarian or trained operator before any physical means of euthanasia is implemented.

Acceptable physical means of euthanasia are stunning followed by decapitation, or stunning followed by pithing.4,5 These methods are only acceptable if the operator is well trained and experienced in the method.

An acceptable chemical means of euthanasia is intracoelomic injection of a veterinary euthanasia solution.

Freezing is not considered an appropriate method of euthanasia.6,7 Research conducted at the School of Biological Sciences, University of Wollongong, to evaluate the methods of euthanasia used in the field, reported by Sharp et al, 20118 showed that;

  • Stunning followed by decapitation was acceptable when carried out by a trained operator.
  • Carbon Dioxide gassing was conditionally acceptable when used for 4 hours
  • The commercially available spray, Hopstop® was conditionally acceptable.

Further research should be carried out to determine the most humane and practical methods of cane toad euthanasia.

Other recommendations

Ideally, designated stations should be created for members of the public to drop off cane toads for euthanasia. Such centres could operate from veterinary clinics, offices of parks and wildlife services, or the premises of other relevant statutory and government departments.

The AVA supports research and development of innovative methods to limit the impact of cane toads on native and domestic species. For example, small scale experiments have shown that if water sources in semi-arid areas are made inaccessible to cane toads, the spread of cane toads can be slowed.9 The preferred characteristics of toad breeding habitat have also been identified and application of these findings could be used to limit cane toad reproduction and spread.10

Researchers have also successfully mitigated impacts in recently colonised areas by ’training’ predators to avoid toads by providing them with dead immature toads laced with an emetic (quolls)11 or with young toads of low toxicity, prior to introduction of adult toads (goannas).12

Other relevant policies and position statements

Humane destruction of animals

Control of native and introduced animals causing damage to agriculture or habitat

References

  1. Turvey N. Cane toads: a tale of sugar, politics, and flawed science. Sydney University Press, 2013.
  2. Greenlees, MJ, Brown, GP, Webb, JK, Phillips, BL & Shine, R. ‘Do invasive cane toads (Chaunus marinus) compete with Australian frogs (Cyclorana australis)? Austral Ecology, 2007; 32:900–907.
  3. Taylor R, Edwards G, editors. A review of the impact and control of cane toads in Australia with recommendations for future research and management approaches. Report to the Vertebrate Pests Committee from the National Cane Toad Taskforce, 2005.
  4. Wright KM. Restraint techniques and euthanasia. In: Wright KM, Whitaker BR, editors. Amphibian medicine and captive husbandry. Krieger, Malabar, FL, 2001;121.
  5. Herpetological Animal Care and Use Committee (HACC) of the American Society of Ichthyologists and Herpetologists. Guidelines for use of live amphibians and reptiles in field and laboratory research, 2nd edn, rev. HACC, 2004;23–24
  6. Mader DR. Euthanasia. In: Medicine and surgery of reptiles. Saunders Elsevier, St Louis, 2006;564–568.
  7. Baier J. Amphibians. In: Guidelines for euthanasia of nondomestic animals. American Association of Zoo Veterinarians, Yulee, FL, 2006;39–45.
  8. Sharp T., Lothian A., Munn A and Saunders G; 2011 CAN001 Methods for the field euthanasia of cane toads
  9. Semeniuk, M., F. Lemckert, and R. Shine. Breeding-site selection by cane toads (Bufo marinus) and native frogs in northern New South Wales. Wildlife Research 2007;34:59-66.

Further reading

Warwick C. Euthanasia of reptiles – decapitation: an inhumane method of slaughter for the class ‘Reptilia’. Can Vet J 1986;27:34.

Reilly JS, editor. Euthanasia of animals used for scientific purposes, 2nd edn. ANZCCART (Australian and New Zealand Council for the Care of Animals in Research and Teaching), Adelaide, 2001.

Schaffer DO. Anaesthesia and analgesia in non-traditional laboratory animal species. In: Kohn DF, Wixson SK, White WJ et al, editors. Anesthesia and analgesia in laboratory animals. Academic Press, San Diego, 1997;337–378.

Webb, J. K., G. P. Brown, T. Child, M. J. Greenlees, B. L. Phillips, and R. Shine.. A native dasyurid predator (common planigale, Planigale maculata) rapidly learns to avoid toxic cane toads. Austral Ecology 2008;33:821-829. Ward-Fear G, Pearson DJ, Brown GP, Balanggarra Rangers, Shine R. Ecological immunization: in situ training of free-ranging predatory lizards reduces their vulnerability to invasive toxic prey. Published 6 January 2016.DOI: 10.1098/rsbl.2015.0863