Bait consumption by, and 1080-based control of, feral pigs in the Mediterranean climatic region of south-western Australia

2007 ◽  
Vol 34 (2) ◽  
pp. 125 ◽  
Author(s):  
Laurie E. Twigg ◽  
Tim Lowe ◽  
Gary Martin

The consumption of five non-toxic, grain-based baits, and the effectiveness of the preferred baits when treated with 1080 in reducing pig numbers, were determined for feral pigs (Sus scrofa) in several areas in the Mediterranean agricultural region of Western Australia. Fermented wheat with added blood and bone proved an effective attractant for feral pigs, and for determining areas of pig activity. Wheat and malted barley were the preferred baits, there was a variable response to lupins, and commercial pig pellets were consumed least. Malted barley, barley, and wheat treated with 1080 gave good reductions in pig numbers at the localised scale. Where pigs would eat lupins, 1080-treated lupins were usually effective in reducing pig abundance. In some instances, further evidence of feral pig activity was not seen on several sites for several months after poison-baiting occurred. The addition of a small amount of unpoisoned grain to mask the presence of 1080 did not increase the take of treated bait (P < 0.05). Although finding poisoned pigs was difficult owing to the terrain and the presence of bush remnants, the poisoned pigs found (n = 90) were often within 200 m of active bait stations. 1080-poisoned pigs included both adult (≥25 kg) and non-adult pigs of both sexes. Body mass of these pigs ranged from 4 to 90 kg. In all, 42% of poisoned adults found (n = 50) were 50 kg or more. There was minimal evidence of bait take by non-target species, and, where this occurred, it generally involved the consumption of the fermented wheat attractant by kangaroos (Macropus spp.) and foxes (Vulpes vulpes). Six foxes were known to have been poisoned with 1080-treated grain (4 with malted barley, 2 with wheat). Excluding foxes, no other non-target animals, including native species, were found dead during the intensive searches for poisoned pigs.

2016 ◽  
Vol 43 (1) ◽  
pp. 61 ◽  
Author(s):  
Clifford Bennison ◽  
J. Anthony Friend ◽  
Timothy Button ◽  
Harriet Mills ◽  
Cathy Lambert ◽  
...  

Context House mice (Mus domesticus) are present on Boullanger and Whitlock islands, Western Australia, and could potentially threaten populations of the dibbler (Parantechinus apicalis) and grey-bellied dunnart (Sminthopsis griseoventer) through competition for resources. A workshop in 2007 recommended a study to assess the feasibility of eradicating house mice from the islands by using poison baits and of the risk posed to non-target native species. Aim We aimed to assess the risk to non-target native species if poison baiting was used to eradicate house mice on Boullanger and Whitlock islands. Methods Non-toxic baits containing the bait marker rhodamine B were distributed on Boullanger Island and on the mouse free Escape Island to determine the potential for primary poisoning. Acceptance of baits by mammals was measured through sampling and analysis of whiskers, and by reptiles through observations of dye in faeces. To determine the potential for secondary exposure to poison, the response of dibblers to mouse carcasses was observed using motion-activated cameras. Bait acceptance was compared using two methods of delivery, namely, scattering in the open and delivery in polyvinyl chloride (PVC) tubes. A cafeteria experiment of bait consumption by dibblers was also undertaken using captive animals held at the Perth Zoo. Ten dibblers were offered non-toxic baits containing rhodamine B in addition to their normal meals; consumption of bait and the presence of dye in whiskers were measured. Key results Bait acceptance on the islands was high for house mice (92% of individuals) and dibblers (48%) and it was independent of bait-delivery technique. There was no evidence of bait acceptance by grey-bellied dunnarts. Dibblers may consume mice carcasses if available; however, no direct consumption of mice carcasses was observed with movement sensor cameras but one dibbler was observed removing a mouse carcass and taking it away. During the cafeteria experiment, 9 of 10 captive dibblers consumed baits. Conclusions This investigation demonstrated that dibblers consume baits readily and island populations would experience high mortality if exposed to poison baits. Poison baiting could effectively eradicate mice from Boullanger and Whitlock islands but not without mortality for dibblers. Implications Toxic baits could be used to eradicate mice from Boullanger and Whitlock islands, provided that non-target species such as dibblers were temporarily removed from the islands before the application of baits.


2005 ◽  
Vol 32 (4) ◽  
pp. 281 ◽  
Author(s):  
Laurie E. Twigg ◽  
Tim Lowe ◽  
Gary Martin ◽  
Michael Everett

Bait consumption, and the efficacy of 1080-treated grain, were determined for feral pigs (Sus scrofa) during the dry season in the Fitzroy River region of north-western Australia. There were an estimated 250 pigs on the study site (15 000-ha paddock with beef cattle) before poison-baiting, and group size and the basic biology of these pigs were similar to that found elsewhere in Australia. All animals at the study site were naive to the test baits. Fermented wheat with added blood and bone was an attractant for feral pigs but added fish oil was not. Wheat and malted barley were the ‘preferred’ baits. Lupins and pig pellets were consumed in lesser amounts, suggesting that they are less/not acceptable to some feral pigs. Consequently, the efficacy of 1080-treated wheat and malted barley was determined (n = 3 sites per treatment). Three independent measures of pig activity/abundance were used. The daily sighting index before and after poison-baiting suggested that pig numbers were decreased by at least 81–100% (mean 89%) regardless of which bait was used. The take of both 1080-bait and non-toxic fermented wheat added to each station generally ceased within 1–3 days, and little take occurred during the post-poisoning follow-up. Pig tracks decreased to zero within 1–3 days of poisoning on the two sites where track plots were established. However, due to the arrival of ‘immigrant’ pigs ~6 days after poisoning on two sites, and the need to close down a third site before poison-baiting could be completed, we believe the absolute efficacy was greater than the 89% overall reduction. Even though they had access to bait, there was no bait-take by non-target species, either native (toxic and non-toxic bait) or domestic (non-toxic bait). The 61 pig carcases found after poisoning were within 20–610 m of active bait stations (mean 232 m), and most were found in clustered groups. These findings are discussed with respect to the development of management strategies for reducing the impacts of feral pigs, and in terms of their potential implications for developing wildlife disease (exotic and endemic) contingency plans.


2006 ◽  
Vol 33 (5) ◽  
pp. 417 ◽  
Author(s):  
Laurie E. Twigg ◽  
Tim Lowe ◽  
Michael Everett ◽  
Gary Martin

The recovery rate of a population of feral pigs (Sus scrofa) in the west Kimberley in north-western Australia was determined 12 months after a 1080 (sodium fluoroacetate)-baiting program. An estimated 56 pigs were present in the 15 000-ha study area in August 2005 compared with the prebaiting levels of 250–275 pigs in 2004 (11 pigs were known to be alive on site after the 2004 baiting). This represents a population recovery of 20–23% of the 2004 prebaiting levels. Although most pigs were in good body condition, environmental conditions were quite different between the two years. In 2005, some waterholes were dry or comprised mainly muddy water with little associated shelter for feral pigs. Consequently, and in contrast to 2004, no pigs were seen, and no bait take could be attributed to feral pigs, at the four resurveyed waterholes. Most pig sightings, and activity, were close to the Fitzroy River. Fermented wheat, with blood and bone, was used to determine areas of pig activity, and also used as prefeed before 1080-baiting commenced in 2005. Using the same bait stations as for 2004, plus additional stations established in new areas of pig activity, 1080-treated wheat and malted barley again proved highly effective in reducing pig numbers. The daily sighting index before and after 1080-baiting indicated that pig numbers had been reduced by ~90% within four days. Estimated pre- and postpoisoning density, with and without an edge effect, was 0.12–1.7 pigs km–2 and 0.05–0.67 pigs km–2. Pig tracks decreased to zero on the six track plots within two days of baiting, but the number of macropod tracks remained constant over the four-day baiting period. Thirty-eight poisoned pigs were found after 1080-baiting, and these were generally in clustered groups within 200 m of an active bait station. Poisoned juvenile pigs were again found closer to the active bait stations than were adult or subadult pigs (P < 0.05).


2011 ◽  
Vol 38 (1) ◽  
pp. 39 ◽  
Author(s):  
Paul J. de Tores ◽  
Duncan R. Sutherland ◽  
Judy R. Clarke ◽  
Robert F. Hill ◽  
Sean W. Garretson ◽  
...  

Context The CURIOSITY® bait is the name coined for a variation of the existing sausage-style cat bait, ERADICAT®. The latter is used under experimental permit in Western Australia for research associated with cat control. The CURIOSITY bait differs from ERADICAT by providing a pH-buffered (less acidic) medium and has been proposed to reduce the risk to non-target species by encapsulating a toxin in a pellet. We trialled a prototype pellet proposed for encapsulation of 1080 and/or alternative toxins, with delivery proposed through the CURIOSITY bait. Aim Our aim was to determine whether the pellet was consumed by non-target native species from south-west of Western Australia. Methods Trials involved use of a non-toxic biomarker, Rhodamine B, encapsulated within the pellet and inserted into the CURIOSITY® bait. Uptake of the encapsulated biomarker was assessed in captive trials for the target species, the feral cat (Felis catus) and two non-target species of varanid lizard, Rosenberg’s goanna (Varanus rosenbergi) and Gould’s goanna (V. gouldii) and the non-target mammal species chuditch (Dasyurus geoffroii) and southern brown bandicoot (Isoodon obesulus). Uptake of the encapsulated biomarker was also assessed in field trials for a range of native species. Key results Captive trials demonstrated feral cats will consume the CURIOSITY bait and pellet. However, results from captive and field trials indicated several non-target species also consumed the bait and pellet. We also found the pellet itself was not sufficiently robust for use in a bait. As with previously reported studies, we found Rhodamine B to be an effective biomarker for use in cats. We also developed a technique whereby Rhodamine B can be used as a biomarker in reptiles. However, its use as a biomarker in other mammalian species was confounded by what appeared to be background, or pre-existing, levels of fluorescence, or banding, in their whiskers. Conclusion The prototype pellet is unsuitable in its current form for use with the CURIOSITY bait. We caution that the CURIOSITY bait has non-target issues in south-west of Western Australia and any proposed variations to this bait, or the ERADICAT® bait, need to be rigorously assessed for their potential risk to non-target species and assessed for the level of uptake by cats, irrespective of their suitability/unsuitability as a medium for delivery of an encapsulated toxin. We believe the threat to biodiversity-conservation values from unmitigated feral-cat predation of native fauna poses a significant and real threat and we recommend urgent investment of resources to address the issue of cat predation in a coordinated and collaborative manner within Australia and New Zealand.


2020 ◽  
Vol 47 (8) ◽  
pp. 547
Author(s):  
Rosemary Hohnen ◽  
Brett P. Murphy ◽  
Sarah M. Legge ◽  
Chris R. Dickman ◽  
John C. Z. Woinarski

Abstract ContextPredation by feral cats (Felis catus) threatens a range of vertebrate species across Australia, and cat-free islands increasingly act as safe havens for biodiversity. A feral cat eradication program has begun on Kangaroo Island (4405km2) in South Australia, and poison baiting is likely to be one of the main methods used. Aims Here, we trial a non-toxic version of a cat bait, ‘Eradicat’, on western Kangaroo Island, to examine its potential impact on non-target species. MethodsNon-toxic baits containing the biomarker Rhodamine B were deployed across four sites in early August and late November in 2018, with bait take and consumption assessed both by remote cameras and by the presence of Rhodamine B in mammalian whisker samples taken post-baiting. Key resultsCats encountered baits on very few occasions and took a bait on only one occasion in August (&lt;1% of 576 baits deployed). Non-target species accounted for over 99% of identifiable bait takes. In both seasons, &gt;60% of all baits laid was taken by either the common brushtail possum (Trichosurus vulpecula), bush rat (Rattus fuscipes) or Australian raven (Corvus coronoides). In November, Rosenberg’s goanna (Varanus rosenbergi) and southern brown bandicoot (south-eastern subspecies; Isoodon obesulus obesulus), listed nationally as Endangered, also took baits (3% and 1% respectively). The Kangaroo Island dunnart (Sminthopsis fuliginosus aitkeni), listed nationally as endangered, approached a bait on only one occasion, but did not consume it. Evidence of bait consumption was visible in the whiskers of captured common brushtail possums (100% of post-baiting captured individuals in August, 80% in November), bush rats (59% in August and 50% in November), house mice (Mus musculus) (45% in November) and western pygmy-possums (Cercartetus concinnus) (33% in November). ConclusionsAlthough feral cat baiting has the potential to significantly benefit wildlife on Kangaroo Island, impacts on non-target species (particularly the bush rat and common brushtail possum) may be high. ImplicationsAlternative cat baits, such as those containing a toxin to which native species have a higher tolerance or that are less readily consumed by native wildlife, will be more appropriate.


2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Melissa L. Karlin ◽  
Harun A. Khan

Abstract Feral pigs are an invasive exotic pest that damage habitat and compete with native species. Trapping feral pigs using a variety of baits or lures is the primary method for eradication, with little success. The purpose of this study was to use a variety of lures, with and without the presence of a mock corral trap, to determine if there was a preferred lure selected even in the presence of a trap. We also identified non-target species attraction to the lures, to identify a preferred choice by feral pigs that minimized these non-target species. We deployed 10 stations from July 2017 to March 2018 and used trail cameras to assess feral pig visitation frequency. The majority of feral pig visitation events occurred at the orange flavored corn without a mock corral trap present (43.20%). There was no significant difference in feral pig visitation rates to stations based on presence or absence of corral, but there were differences based on lure: orange corn had a significantly higher visitation rate than any other lure type. The plain corn station without a corral had only 15% of the feral pig visitation events, while the majority of non-target species (i.e., axis – 45.93%, white-tailed deer – 39.42%, and raccoon – 85.38% of visitation events) were associated with this bait. For these reasons, we suggest that orange flavored corn may be the better primary attractant in feral pig management activities in south Texas.


2006 ◽  
Vol 33 (8) ◽  
pp. 651 ◽  
Author(s):  
Brendan D. Cowled ◽  
Steven J. Lapidge ◽  
Michelle Smith ◽  
Linton Staples

Following a bait-preference pilot study on captive feral pigs, a series of field studies assessed the attractiveness and target-specificity of a prototype manufactured feral pig bait (PIGOUT®). Two promising test baits and fresh meat reference baits were biomarked with iophenoxic acid and aerially distributed in 100-km2 blocks of land infested with feral pigs in western Queensland to assess field uptake and target-specificity without prefeeding. Uptake was assessed by measuring blood iodine levels in aerially shot feral pigs. In all, 80% of feral pigs sampled in a non-toxic PIGOUT®-baited area had significantly elevated blood iodine, compared with 52% of sampled feral pigs in a meat-baited area (although slightly different baiting strategies were employed). No age or sex bias was evident in PIGOUT®-consuming feral pigs. No monitored manufactured baits were consumed by non-target species in 500 bait-nights. Attractiveness and target-specificity trials of ground-laid, unfenced PIGOUT® baits compared with reference baits were subsequently undertaken in several regions of eastern Australia. Results showed that PIGOUT® was consumed readily by feral pigs at all sites, and that it offered significant improvement in target specificity when compared with unfenced wheat or meat baits. However, the baits were consumed by small numbers of macropods, birds and possums. Available evidence indicates that the target-specificity of PIGOUT® bait is highest in the rangelands, reducing slightly in temperate areas and subalpine forests, where abundance of small animals is higher.


1983 ◽  
Vol 10 (1) ◽  
pp. 139 ◽  
Author(s):  
JC Mcilroy

Acute oral LD50S (median lethal doses) and 95% confidence limits of 1080 poison for feral pigs, Sus scrofa, obtained by moving average and probit analysis methods are 1.04 (0.84-1.27) mg kg-1 and 1.00 (0.72-1.28) mg kg -1 respectively. These values are slightly higher than LD50S obtained for pigs by i/p dosing but similar to those obtained by oral dosing for other eutherian mammals. Signs of poisoning, either vomiting or increasing lethargy and laboured respiration, appeared from 1.9 to 47.3 h (median 6.2 h) after dosing, and deaths from 2.8 to 80 h (median 16.1 h) after dosing. Although 1080 is one of the most toxic poisons for pigs it has disadvantages, including the relatively large amounts that must be distributed in baits to kill pigs, and the comparatively greater susceptibility to it of many non-target birds and mammals. 36 species out of 40 non-target species likely to feed on poisoned baits are more susceptible to 1080 than pigs. Many other factors such as bait acceptance will govern what proportions of target and non-target populations will be poisoned. Attention to methods of poisoning or baiting techniques could minimize the risk that non-target animals face from pig-poisoning campaigns.


2001 ◽  
Vol 28 (6) ◽  
pp. 607 ◽  
Author(s):  
Laurie E. Twigg ◽  
Neville E. Kok ◽  
Winifred E. Kirkpatrick ◽  
Geoff Burrow

The longevity of 1080 in egg-baits (4.5 mg 1080 per egg) used for fox control was monitored at the Corackerup Nature Reserve, Western Australia. Irrespective of season, most egg-baits (94%) were found to retain sufficient 1080 to be theoretically lethal to all foxes for at least 42 days, and 75% of baits contained an LD50 of 1080 at Day 63. Exponential decay curves also predicted that these baits would remain toxic to most foxes for up to 32 weeks, depending upon environmental conditions. Sealing the injection hole with wax, or using sterile techniques to prepare some egg-baits, appeared to have little effect on the longevity of 1080 in these baits compared with that of unsealed eggs. Bait take, and identification of those species taking bait, were monitored over 12 days at 216 permanent bait stations in the reserve. Track plots were present for 3–6 days on 83 of these stations in spring and summer but not in winter. In spring and summer, of those species likely to take bait, goannas were the most frequent visitors to the track plots and they were also responsible for most of the baits taken at this time (59% and 90% of baits taken). Foxes accounted for 27% (spring), 8% (summer) and 75% (winter) of the egg-baits taken. No egg-baits were taken by goannas in winter, but the overall bait take was also low at this time (28 of 211 baits laid; 13%). Overall bait take after 12 days in spring and summer was 64% (135 of 211) and 68% (145 of 212) of baits laid. Except for goannas, birds and other non-target species (e.g. bob-tail skink) took relatively few baits in any season. The implication of these findings for 1080-based predator-control programs are discussed.


Author(s):  
Andrea Petetta ◽  
Massimo Virgili ◽  
Stefano Guicciardi ◽  
Alessandro Lucchetti

AbstractStock overexploitation, bycatch, discards and gear impacts on the environment are outstanding issues for Mediterranean fisheries. The adoption of alternative fishing gears is an appealing solution to ensure a more sustainable exploitation of resources. We discuss the pros and cons of pots as alternative gears by reviewing their main designs, spatial distribution and target species in the Mediterranean basin. We assessed the technical factors affecting the catch efficiency of the different pot designs for four target species: spiny lobster, Palinurus elephas; Norway lobster, Nephrops norvegicus; common octopus, Octopus vulgaris and pandalid shrimps, Plesionika spp. We found that pot volume is important to catch Octopus; mesh size to catch Nephrops and Plesionika; entrance surface to catch Octopus, Nephrops and Plesionika; pot shape/colour and entrance shape/position to catch Octopus and Plesionika; and bait type to catch Octopus and Nephrops. The literature review shows that pot fisheries have several considerable advantages over conventional gears, especially in terms of discards, bycatch, seabed impacts (particularly compared with bottom trawls and passive set nets), size and species selectivity, gear depredation, catch quality and gear cost, besides saving time and labour. Disadvantages hampering their wider diffusion include ghost fishing, a low catch of finfish species, the narrow range of species targeted by each pot design and the current early stage of research. These data make a clear case for using pots as alternative gears to traditional ones in the Mediterranean Sea in some areas and seasons to catch certain target species.


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