The use of 1080, a pesticide using sodium fluoroacetate, is a contentious issue in New Zealand, with the majority of the debate occurring between conservationists and hunters.
- Controlling conservation pests
- Controlling agricultural pests
- Neutral stance
- Comparing pest control methods
- Pindone diphacinone and coumatetralyl
- Para aminopropiophenone
- Zinc phosphide
- Sodium nitrite
- Biological control
Although the use of 1080 in New Zealand was deemed "effective and safe" by the Parliamentary Commissioner for the Environment in a 2011 re-evaluation and is widely considered to be the most effective tool currently available for controlling possums over large areas, it remains a contentious issue, with the majority of the debate occurring between conservationists and livestock farmers on one side and hunters and animal rights activists on the other. Concerns are also raised about security of potable water supplies in areas where 1080 is applied.
New Zealand is the largest user of biodegradable 1080 poison, using about 80% of the world's supply. Biodegradable 1080 poison is the only poison currently registered for use on mainland New Zealand as suitable for aerial targeting of the common brushtail possum - a major conservation and agricultural pest. It has been used as such since the late 1950s. Sodium fluoroacetate is imported in a raw form from the United States.
The largest users of 1080 in New Zealand are the Animal Health Board and the Department of Conservation (DOC). It is also used on a smaller scale for pest control by Regional Councils and private landowners. The first trials were carried out in New Zealand in 1954, and by 1957 its use had become widespread. 1080 baits are used through ground-based and aerial application. 1080 is considered to be suitable for use as a mammalian pest control in New Zealand because the country has only two native land mammals (bats). It should also be noted that 1080 is commonly used in Western Australia to kill feral carnivores, as the compound is naturally occurring in Western Australian flora and the native herbivores and their native predators are immune.
Controlling conservation pests
New Zealand's flora and fauna evolved for 80 million years with moa being the primary browsing animals and no predatory mammals. Consequently, the native birds, insects, and flora have developed no natural defence mechanisms against introduced animals such as possums, rats, mustelids and feral cats. These exotic species have become ecological pests, and their presence has had a disastrous effect on the populations of many endemic species, including the national symbol, the kiwi bird. Populations of the reptile tuatara have also been severely impacted. An estimated 30 million possums inhabit New Zealand, and they are found in 98% of vegetated areas on mainland New Zealand.
When correctly applied, 1080 is very effective at controlling conservation pests. One aerial application can kill 98% of possums and more than 90% of rats in the targeted area. These successful knock-down rates provide vulnerable native birds with a crucial breeding window to raise chicks through to fledging, increasing their survival rate. The DOC uses aerially applied 1080 poison across about 440,000 ha of conservation land each year. This equates to 5% of the total conservation estate.
Controlling agricultural pests
In New Zealand, the common brushtail possum was the main vector for the spread of bovine tuberculosis - a highly contagious disease affecting farmed cattle and deer. The disease was endemic in possums across about 38% of New Zealand (known as ‘vector risk areas’) but industry sources acknowledge the incidence of Bovine Tuberculosis has now fallen to less than 0.05% in the areas where it is monitored. The organisation responsible for managing bovine TB in New Zealand — the Animal Health Board - uses 1080 poison as one of a range of pesticides to kill possums and control the spread of disease to both livestock and unaffected areas of the country. Aerial application of 1080 poison is only used in places where ground control methods are impractical or unable to knock possum numbers down to a low enough level to break the disease cycle. In 2011, this was less than 10% of the total area receiving possum control.
Both aerial and ground-based application of 1080 poison is also used to control rabbits — an introduced grazing pest. By 1960, it had become the main poison used in rabbit control. The combination of aerial spreading and the use of carrots poisoned with 1080 enabled rabbit boards (which were responsible for rabbit destruction work) to reduce rabbit numbers in most areas by the early 1960s.
The use of 1080 poison in New Zealand has been the topic of a long-established and complex debate. In general, the majority of conservationists and livestock farmers support the continued use of 1080 for pest control, while the hunting community, animal rights groups and antifluoride campaigners support a ban, but there are exceptions on both sides.
Organised opposition is usually small-scale and localised to areas where aerial 1080 operations are carried out. Protest is generally peaceful, but there have been occasions where opponents have resorted to violence or sabotage.
In August 2007, the Environmental Risk Management Authority released its latest review of 1080 use. The review gave new guidelines for the use of the pesticide in New Zealand, and concluded the beneficial effects of pest eradication outweigh the risks. 1080 decomposes in warm water into harmless compounds, resulting in low persistence in a lab environment, but in the natural New Zealand environment, its decomposition rates and persistence are unknown.
In June 2011, the Parliamentary Commissioner for the Environment (PCE) released a report in favour of 1080 to control possums, rats, and stoats, especially in large and remote areas. It is seen as an effective poison for aerial spreading. The PCE came to a number of conclusions, including not having a moratorium on 1080 use, and setting up a Game Animal Council. In June 2011, New Zealand's four largest daily newspapers all ran editorial pieces questioning the need for continued debate in light of the Parliamentary Commissioner for the Environment's report.
Support for the use of 1080 is mixed amongst the political parties currently in government.
In 2004, anti-1080 activist Phillip Anderton posed for the New Zealand media with a kiwi he claimed had been poisoned. An investigation revealed that Anderton lied to journalists and the public. He had used a kiwi that had been caught in a possum trap.
On 10 March 2015, the New Zealand Police revealed that anonymous blackmail threats were sent to Fonterra and Federated Farmers. The threats warned that infant formula in supermarkets would be poisoned unless the use of 1080 was halted by the end of the month. The ensuing police response Operation Concord led to charges laid against a 60 year old businessman Jeremy Hamish Kerr, who was alleged to have made the threats for potential financial gain. He pleaded guilty to two charges of blackmail and in March 2016 was sentenced to 8 years 6 months imprisonment.
The following agencies, organisations, and political parties support the use of 1080 in New Zealand:
These organisations and political parties oppose the use of 1080 in New Zealand:
These organisations and political parties have a neutral stance on the use of 1080 poison in New Zealand:
Biodegradable 1080 poison is the only pesticide currently registered for use on mainland New Zealand as suitable for aerial targeting of possums. While many research teams are actively seeking new and supplemental approaches to current technologies, no method has yet gained widespread acceptance as a viable alternative to 1080.
New Zealand currently spends at least $8 million annually on improving existing pest control technology and developing new methods.
According to the EPA's Annual Report on the Aerial Use of 1080, as of October 2011 there are currently over 50 research projects underway industry-wide to find improvements in the use of 1080, alternatives to 1080 and other related topics.
Comparing pest control methods
In the Parliamentary Commissioner for the Environment's June 2011 re-evaluation of 1080, these questions were used for assessing the effectiveness and safety of 1080, as well as current and prospective alternatives
1. Can the method decrease populations of possums, rats and stoats?
2. Can the method increase populations of native species?
3. Can the method rapidly knock down erupting populations of pests?
4. Can the method be used on a large scale in remote areas?
5: Is the method sufficiently cost-effective?
6. Does the method leave residues in the environment?
7. Can by-kill from the method be minimised?
8. Does the method endanger people?
9. Does the method kill humanely?
The Parliamentary Commissioner for the Environment's conclusion with regards to 1080 was, "It is not perfect, but given how controversial it remains, I for one expected that it would not be as effective and safe as it is".
The Parliamentary Commissioner reached the following conclusions regarding the possible alternatives to 1080 poison currently available in New Zealand.
Pindone, diphacinone, and coumatetralyl
Pindone, diphacinone, and coumatetralyl are the first-generation anticoagulants most commonly used for pest control. They are generally very effective at controlling rats to keep their numbers low, but cannot effectively deal with sudden population surges. Anticoagulants break down very slowly in water and soil. They also accumulate in the liver tissue of live animals that have been exposed to the poison (either by eating bait or feeding on an animal that has eaten bait) and in carcasses. They are also the most inhumane of the poisons currently used. By-kill of native species is a significant risk from the use of first-generation anticoagulants. Different types of anticoagulants need to be rotated to avoid populations becoming bait-shy or building up resistance.
Brodifacoum is a second-generation anticoagulant. It is licensed for killing possums and rats. Like 1080, it will kill stoats that feed on poisoned animals. It has been successfully used in aerial operations to completely eradicate possums, rats, and stoats on several offshore islands and fenced ‘mainland islands’ that are now sanctuaries for endangered animals, but it is not currently registered in New Zealand for general aerial use on the mainland. Brodifacoum takes a very long time to break down in soil and water and accumulates in the tissue of exposed animals for years. Consequently, there is a very high risk of by-kill – it is known to have killed at least 21 species of native birds, including kiwi, kākā, kākāriki and tūī. It is also widely considered a very inhumane poison.
Cyanide has been used in New Zealand since the 1940s, and is licensed for killing possums and wallabies. It is a highly lethal, broad-spectrum poison that depletes cells of energy, quickly resulting in respiratory arrest and death. Ground-laid cyanide has killed native species and other animals in the past (including kiwi, kea, weka, and bats) and it takes only a tiny amount of cyanide to kill a human. While there are antidotes to cyanide poisoning, their effectiveness is controversial and the rapid action of the poison limits the time in which they can be used. Its effectiveness varies because of bait shyness.
Cholecalciferol naturally occurs as vitamin D3 in many foods, including fish. It was developed as a poison to control rats and mice in the 1980s. It works by leaching calcium from the bones of the poisoned animal into its bloodstream, leading to organ failure. Cholecalciferol will reduce populations of possums and rats, but not stoats, since it does not bioaccumulate in animals. It breaks down readily in the environment and the risk of by-kill is considered to be low. Cholecalciferol is more expensive to produce than 1080. Some promising results have been obtained by combining cholecalciferol with other substances, such as aspirin, to make it more cost-effective and faster acting. Cholecalciferol is very inhumane.
Para-aminopropiophenone (PAPP) was developed to control stoats, weasels, and feral cats, and registered for use in New Zealand in 2011. It kills by preventing red blood cells from carrying oxygen. PAPP kills stoats directly, but not possums and rats. It is approved for use in paste form or in fresh minced meat, so will only provide effective stoat control as part of intensive ground control. The risk of by-kill is likely to be low since it does not leave residues in the environment.
Zinc phosphide (microencapsulated zinc phosphide paste) has been widely used overseas for decades, predominantly to control rats and mice on agricultural land. It causes death by heart or respiratory failure. In August 2011, the New Zealand Environmental Protection Authority approved the import and manufacture of microencapsulated zinc phosphide (MZP paste) as an alternative to 1080 for the ground control of possums. The application was made by Pest Tech Limited, with support from Connovation Ltd, Lincoln University, and the Animal Health Board. It will be used as an additional vertebrate poison in certain situations. Unlike 1080, it cannot be used for aerial application.
Sodium nitrite is a naturally occurring substance commonly used as a meat preservative, but toxic at higher doses. It kills in a similar way as PAPP, by reducing the ability of red blood cells to carry oxygen (methemoglobinemia). Sodium nitrite is expected to be registered for use in for killing possums, but not rats. It will not control stoats because it will not knock down rat populations or bioaccumulate in poisoned animals. It does not leave residues in the environment and the risk of by-kill is expected to be low. It is much more humane than 1080.
Ground operations of which trapping is an important component have been shown to help populations of native birds. Possums, rats, and stoats can all be killed with traps. However, an intensive ground operation will typically involve trapping possums and stoats, but poisoning rats because there are so many more of them. In a mass event, populations of rodents rapidly increase as much as ten-fold, and traps simply cannot be deployed rapidly enough or in sufficient numbers to knock them down.
Some terrain is too rugged or dangerous for trapping, and trapping is not practical on a large scale. In one day, a single trapper can check traps on tens of hectares, whereas an aerial 1080 drop can cover tens of thousands of hectares. Once a trap has ‘snapped’, it will not catch another animal unless it is reset. Traps need to be checked and reset regularly, which makes them labour-intensive. Self-resetting traps, such as the Goodnature trap, are being developed and trialled, and could in the future significantly reduce labour costs and increase the cost-effectiveness of ground control operations.
Twenty three species of native birds have been reported as having been killed by leg-hold traps, and many kiwi have suffered leg or beak damage. These traps are now required to be set up off the ground on conservation land where kiwi or weka (which are ground-dwelling birds) live.
Biological control has been likened to the 'Holy Grail' of pest control by a number of sources, and was a major focus for research funding during the 1990s and 2000s in both New Zealand and Australia. Most of the methods proposed involved some form of genetic engineering, and if developed further would attract a great deal of public opposition. No biological control method has therefore yet gained widespread acceptance as a viable alternative to 1080.