THE EVALUATION OF ALTERNATIVE TOXINS TO SODIUM MONOFLUOROACETATE (1080) FOR POSSUM CONTROL

Possum control in New Zealand is dependent on the use of sodium monofluroacetate (1080) and cyanide. Although 1080 is highly effective, its use is restricted to government staff. Cyanide is available for a wider group of licensed operators, but cyanide shyness reduces its effectiveness. An acute toxicity program has been set up to identify nonanticoagulant toxins that could be used safely by farmers. Dose-ranging studies showed that possums are susceptible to cholecalciferol, calciferol, gliftor, alpha-chloralose, and nicotine, but not to bromethalin. As lethal doses for these toxins have been ascertained, which of them are likely to be cost-effective and safe alternatives to 1080 now needs to be established. Bait palatability and field studies will then be undertaken with the most promising candidates

Sodium fluoroacetate (1080) in relation to its use in New Zealand revisited: A 2021 review

Traps, poisons and hunting are pest control tools used internationally for crop protection and to restore ecosystems, particularly on islands and continents where introduced mammals endanger native species. Sodium fluoroacetate (1080) is a vertebrate pesticide, initially developed in the 1940s, principally used to control unwanted introduced mammals in New Zealand and Australia. During the last ten years, there have been over 260 new research and review publications, specifically on 1080 in scientific journals. These publications supplement a body of scientific information regarding mode of action, natural occurrence, toxicology, including poisoning incidents and antidotes, metabolism and fate in the environment and risk to non-target species. Multi-year studies now go beyond immediate non-target impacts and explore ecosystem-level outcomes, including population-level changes for multiple native bird species following the sustained removal of predators. Numerous review publications on community attitudes to pest control and the merits of different tools and techniques have been stimulated, in part by the Predator Free NZ 2050 campaign, and these are summarised. Many sectors of our communities would prefer not to use poisons for pest control, particularly if applied aerially. If 1080 is to continue to be used in New Zealand, research still needs to focus on additional improvements in target specificity, particularly concerning the interactions of kea and game species with bait, and address any new questions raised by regulatory agencies such as the Environmental Protection Agency (EPA; formally ERMA), communities, and iwi. Additionally, there is a need to innovate how different pest control tools are used and advance close-to-market tools with the highest public acceptance, such as species-specific poisons and more targeted bait delivery or trapping systems. Community engagement should continue to be open and transparent, highlight risks and benefits, and seek consensus. In most cases, consensus will involve an integrated approach to pest control using acceptable levels of both aerial and ground-based tools. Greater acceptance of any pest control tool occurs when use is discussed within the context of long-term goals for saving endangered species and ecosystem recovery, with communities that treasure the restoration of their landscapes. However, values are changing, such that no (or minimal) pesticide use is a theme that is increasingly mainstream. In this changing environment, strategies that rely on 1080 or other toxins as one-off treatments for eradicating pests or disease versus continued application for maintenance control are likely to be more and more important

An updated review of the toxicology and ecotoxicology of sodium fluoroacetate (1080) in relation to its use as a pest control tool in New Zealand

Sodium fluoroacetate (1080) is a vertebrate pesticide, originally developed in the 1940s and principally used for the control of unwanted introduced animals in New Zealand and Australia. Fluoroacetate is also a toxic component of poisonous plants found in Australia, Africa, South America, and India. In relation to its use as a pesticide, recent research has focused on further elucidation of its potential sub-lethal effects, on animal welfare issues, on understanding and reducing its risk to non-target species, on its ecotoxicology, and fate in the environment following use in baits. 1080 acts by interfering with cellular energy production through inhibition of the tricarboxylic acid cycle and lethal doses can kill animal pests within 6–48 h of eating baits. Exposure to sub-lethal doses has been shown to have harmful effects on the heart and testes in animal studies, and strict safety precautions are enforced to protect contractors and workers in the pest control industry. Considerable care must be taken when using 1080 for the control of animal pests. Primary poisoning of non-target birds and secondary poisoning of dogs must be minimised to ensure that benefits in terms of conservation outcomes and pest and disease control significantly outweigh the risks associated with its use. Despite over 60 years of research and practical experience, the use of 1080 is still embroiled in controversy, while research efforts continue to improve its target specificity when it is used as a conservation tool or for Tb vector control

Toxicology and ecotoxicology of para-aminopropiophenone (PAPP) – a new predator control tool for stoats and feral cats in New Zealand

Para-aminopropiophenone (PAPP) paste was approved as a stoat control agent in New Zealand by the Environmental Protection Authority in August 2011 and for feral cat control in November 2011. PAPP was originally researched in Europe and the USA as treatment for cyanide and radiation poisoning. Over the last 10 years, our research has focused on several factors, including determining its toxicity to predators, field effectiveness for controlling stoats and feral cats, animal welfare profile, toxicology, ecotoxicology, and understanding and reducing non-target risks. PAPP has been developed specifically for the control of stoats and feral cats because of the special sensitivity displayed by these species. Its toxicity is mediated by the induction of methaemoglobinaemia (the ferric state of haemoglobin). Normally, methaemoglobin levels in the blood are below 1%. Levels of methaemoglobin in the blood above 70% are usually fatal, creating a lethal deficit of oxygen in cardiac muscle and the brain. In stoats and feral cats, death after a lethal dose usually occurs within 2 h after eating bait, with clinical signs first appearing in 10 to 20 min for stoats and at around 35 min for cats. Animals become lethargic and sleepy before they die, hence PAPP is relatively humane. A simple antidote exists, namely methylene blue. Further, birds display a lack of toxicity to PAPP when compared with other vertebrate pesticides. A paste containing 40% PAPP has been developed for use in meat baits in New Zealand. A toxic dose for stoats and feral cats is achieved when pea-sized amounts of paste are delivered in 10–20 g meat baits. When meat baits containing PAPP are applied in bait stations in field settings, stoat and feral cat numbers can be rapidly reduced. However, there has been limited practical experience with PAPP to date, especially when compared with alternative tools such as traps or sodium monofluoroacetate (1080) baits. Additional practical experience should enable the effective use of PAPP as a tool to help protect native species from introduced predators. In the future, PAPP will be developed in long-life bait and in a resetting toxin delivery system

Encapsulated sodium nitrite as a new toxicant for possum control in New Zealand

Sodium nitrite (NaNO₂), a commonly used food preservative, has been researched in New Zealand for the control of brushtail possums (Trichosurus vulpecula). In sufficiently high doses, NaNO₂ is toxic because it disrupts circulatory transport of oxygen. As NaNO₂ is very bitter, encapsulation and mixing it through a highly palatable bait formulation is necessary to effectively deliver it to target pest species. In no-choice cage trials, 12/12 possums consumed a lethal dose of toxic paste bait and died on average after 95.6 minutes (±4.9 SE). In two-choice cage trials 7/8 possums consumed a lethal dose of toxic paste bait and died on average after 96.7 minutes (±11.4 SE). Two field trials targeting possums using this toxic paste in bait stations reduced their abundance by 81.2% (± 2.5% SE) and 72.7% (± 1.6% SE) respectively. NaNO₂ paste, known as BaitRite, has been registered in New Zealand as a vertebrate toxic agent for controlling possums

Benefits and risks of including the bromoform containing seaweed Asparagopsis in feed for the reduction of methane production from ruminants

The agricultural production of ruminants is responsible for 24% of global methane emissions, contributing 39% of emissions of this greenhouse gas from the agricultural sector. Strategies to mitigate ruminant methanogenesis include the use of methanogen inhibitors. For example, the seaweeds Asparagopsis taxiformis and Asparagopsis armata included at low levels in the feed of cattle and sheep inhibit methanogenesis by up to 98%, with evidence of improvements in feed utilisation efficiency. This has resulted in an increasing interest in and demand for these seaweeds globally. In response, research is progressing rapidly to facilitate Asparagopsis cultivation at large scale, and to develop aquaculture production systems to enable a high quality and consistent supply chain. In addition to developing robust strategies for sustainable production, it is important to consider and evaluate the benefits and risks associated with its production and subsequent use as an antimethanogenic feed ingredient for ruminant livestock. This review focuses on the relevant ruminal biochemical pathways, degradation, and toxicological risks associated with bromoform (CHBr3), the major active ingredient for inhibition of methanogenesis in Asparagopsis, and the effects that production of Asparagopsis and its use as a ruminant feed ingredient might have on atmospheric chemistry

LRFD Procedure for Piles with Pilot Hole in Rock

PI# 0016891A pile driven into the ground gets its bearing capacity from skin friction along the pile surface as well as from end resistance at the toe. The load transfer mechanism determines how much load is carried by the shaft and by the toe. In Georgia, when a hard/dense layer exists in the pile length or the vibration/noise during the driving causes secondary issues, a pilot hole is often adopted as a pile-driving assistance method to aid driving displacement piles through, especially if a competent hard rock layer exists in a reasonable depth. The use of a pilot hole reduces construction time and uncertainties related to driving through the problematic layers. However, it also reduces the side resistance within the drilled zone due to the disturbance and size of the hole. This process also complicates the prediction of long-term pile capacity. An objective of this study was to identify and document the current guidelines available and adopted by different states, and investigate the relationship between the load capacity of piles installed in rock and their design parameters with respect to the pilot hole, rock conditions, and installation method. Another objective was to identify a reliable design procedure that incorporates proper LRFD resistance factors, and a field verification method for quality assurance of rock. A compilation of best practice methods was necessary, which includes a literature review, a survey with state highway agencies, field tests, a review of past projects and testing data, and making final conclusions. Through these efforts, it is found that most states using a pilot hole in rock, the hole size is larger that the pile and the skin friction is ignored for the nominal resistance. In addition, geotechnical aspects control the design in soft rock, whereas structural aspects control the design in hard rock. Some states do not run a field test but use refusal/end of driving criteria for piles driven into rock. Nevertheless, PDA can be applied to the piles with a pilot hole on rock to check the internal stress to avoid the damage during striking. Moreover, it can verify the structural capacity of the pile if not the geotechnical capacity due to the higher bearing capacity on rock

Bioavailability of Orally Administered Active Lipid Compounds from four Different Greenshell™ Mussel Formats

Abstract: Greenshell™ mussel (GSM, Perna canaliculus) is New Zealand’s most important aquaculture species. They are a good source of long chain-polyunsaturated fatty acids (n-3 LC PUFA). Beyond a traditional food product, GSMs are also sold as mussel powders and oil extract formats in the nutraceutical markets. In this study, a four-sequence, single dose, randomized crossover human trial with eight evaluable healthy male participants was undertaken to determine the bioavailability of the n-3 LC PUFA in four different GSM formats (oil, powder, food ingredient and half-shell unprocessed whole mussel) by measuring area under the curve (AUC) and maximal concentration (CMax). Blood samples were collected at baseline and up to 48 h after initiation of product consumption in each administration period. There were minor differences between the bioavailability of FA (fatty acid) between the different GSM formats. Eicosapentaenoic acid (EPA) peak concentrations and plasma exposures were significantly lower with GSM oil compared to GSM half-shell and GSM powder formats, which resulted in AUC0–48 for the intake of GSM half-shell mussel and GSM powder being significantly higher than that for GSM oil (p = 0.013, f= 4.84). This equated to a 20.6% and 24.3% increase in the amount of EPA present in the plasma after consumption of half-shell mussels and mussel powder respectively compared to GSM oil. GSM oil produced the shortest median time to maximal plasma n-3 LC PUFA concentration of all evaluated products demonstrated by a shorter maximum measured plasma concentration (TMax = 5 h). Docosahexaenoic acid (DHA) and n-3 LC PUFA plasma exposure parameters were statistically comparable across the four GSM products evaluated