Peter Adams

Understanding the movement patterns of invasive animals, particularly feral ungulates, is essential for managing their populations and assessing risks of pathogen spread among and between populations. Disease spread simulations currently consider how movement behaviours affect the model; however, they do not currently assess the risk of atypical movements to influence disease spread. Here, we describe the atypical movement of a GPS-collared Australian feral pig (Sus scrofa) that was translocated (~12.5 km) prior to release. The feral pig travelled over 400 km during 34 days of GPS tracking (averaging > 11 km day−1), more than triple the average daily movement distance of other non-translocated collared pigs within the same study area (x̄ = 3.17 km day−1, n = 19). This observation suggests that translocation could substantially influence feral pig movement behaviour, with potential implications for disease dynamics and management strategies.

Context
Quantifying marine turtle-nest depredation by daily observer monitoring requires substantial labour.

Aims
To quantify nest depredation of the Vulnerable flatback turtle (Natator depressus) at one of its largest rookeries and to compare effectiveness of different monitoring methods.

Methods
We used daily observer monitoring and passive infrared-camera traps separately or in combination to record nest depredation, and identified impacts on remaining eggs and hatchlings in depredated nests.

Key results
More than a quarter (28%) of the 69 monitored nests were confirmed as depredated, although this figure is an underestimate of total losses because camera traps detected twice as many depredation events (39%) as did direct observation (17%) (P = 0.012). Cameras also provided important behavioural data and identified predators. Although reptile and bird predators were also recorded, the introduced red fox (Vulpes vulpes) was the primary predator identified, digging into 26% of the monitored nests. More than half of the depredation events by foxes (58% or 11/19 nests) occurred late term, between turtles hatching and emerging from the nest, which therefore means that losses calculated through counts of eggshell left in the nest are underestimates because predation of hatchlings is not included by the eggshell count method. Furthermore, almost half (42%) of all depredated nests were depredated more than once, with some nests opened up to five times, potentially exacerbating clutch losses due to environmental exposure.

Conclusions
Egg losses for confirmed depredated nests (27 ± 37%, range 0–100%) were three times the background levels (i.e. 9.3% of eggs that failed to hatch as a result of embryo death during development).

Implications
The results of this study strongly warrant the implementation of ongoing fox predator monitoring and mitigation strategies to protect nests at this nationally, and internationally, conservation-significant population of flatback turtles.

The red fox (Vulpes vulpes) is one of the most adaptable carnivorans, thriving in cities across the globe. We used GPS-tracking of five suburban foxes across high-density residential suburbs of Perth, Western Australia to quantify (1) their habitat selection and (2) home range area. All five foxes showed statistically significant avoidance of residential locations (p < 0.001) and preference for parkland (p < 0.001), with native vegetation reserves, golf courses, and water reserves showing disproportionately greater use. Landuse category also influenced their movements, with foxes moving quickest (i.e., commuting) in proximity to roads and slowest (i.e., foraging) when they were further from roads. Three females had core home ranges (50% autocorrelated-corrected kernel density estimate; AKDEc) averaging 37 ± 20 ha or 95% AKDEc averaging 208 ± 196 ha. One male had a 95 ha core home range and 349 ha 95% AKDEc but the other male covered an area ~ 20 times this: using a 371 ha core home range and 7,368 ha 95% AKDEc. The extensive movement patterns we describe are likely to be common for urban foxes, with half of published home range estimates for urban foxes (principally based on VHF data) excluding data for ‘lost’ individuals or animals that showed ‘excursions’. It is likely that the home range estimates for these urban exploiters have therefore been grossly underestimated to date. Further application of GPS trackers that allow remote download will vastly improve our understanding of habitat preference and exploitation of resources by urban foxes.

The introduction of European red foxes in Australia in the late mid-nineteenth century has resulted in the spread of this invasive species across the continent. The morphological and functional divergence of this relatively recently introduced population has not been explored to date, yet it may provide unique insights into adaptability of this widespread carnivore to very different environments. Here we used three-dimensional geometric morphometric approaches and dissections to explore differences in mandible form and function between two populations: one from France and the other from Western Australia. Bite force was predicted for Australian foxes using partial least squares (PLS) regression models based on the observed covariation between estimated bite force (from muscle dissections) and mandible form in French foxes. Muscle contributions were estimated based on Euclidean distances between landmarks that provide insights into muscle lever arms. Despite the greater sample size, Australian foxes show reduced variability in mandible shape compared with French foxes. The mandibles of adult French foxes tend to be slightly smaller and they also strongly differ in shape from the Australian foxes in functionally important areas of the mandible such as muscle insertion areas. This is accompanied by significant differences in the predicted bite force, even relative to size, and muscle contribution: the bite of Australian foxes is weaker and they show greater use of their temporalis muscle compared to French foxes. The reduced variability suggests a founder effect or stabilizing selection on a specific morphology, which was supported by statistical tests. The corresponding anatomical traits suggest different functional demands likely due to differences in diet or competition. Future studies investigating the drivers of variation in mandible shape in native and invasive populations, including data from the original source of the Australian introductions, are needed to better understand the observed differences.

Context: Accidental poisoning of domestic dogs is a potential risk when using baits to control invasive animals. We developed and trialled an electrical device attached to a non-toxic bait to assess whether we could induce a learned aversion towards baits in conservation-working dogs.

Aims: We tested the device on conservation-working dogs licenced to enter conservation estate as part of feral pig control, and consequently are potentially exposed to lethal baits for controlling red foxes.

Methods: Over 1 year (up to seven separate training sessions per dog), 27 dogs were sequentially presented with electrified and non-electrified non-toxic baits and their behavioural responses were recorded. On-farm training (Days 0, 1, 7, Months 1, 12) comprised dogs being called by their owner standing nearby the electrified bait. If the dog touched the bait and demonstrated aversive behaviour (we assume that it received an electric shock or ‘correction’), it was then presented with a non-electrified bait. If they ate either bait, they were shown another electrified bait (up to three electrified baits per session).

Key results: Seventeen dogs (17/27) touched the bait and received a correction. Eleven dogs required only a single correction and did not touch another bait, three dogs needed two corrections, and two dogs needed three or four corrections. These 17 dogs showed increasing avoidance to the bait over successive training sessions (χ212 = 67.96, P < 0.001), including avoiding looking at the bait, refusing to come within 5–10 m of the bait and their owner, or leaving the training vicinity. All these dogs (17/17) avoided baits encountered in a working environment (1/17 touched but did not consume a bait) and bait-aversion was still detected up to 1-year post-initial training. Nine dogs (9/27) did not appear to receive a correction or show any change in bait-aversion behaviour. One dog (1/27) showed no aversion to the stimulus and continued to eat baits.

Conclusions: Here we present a proof of concept for a deterrent device and associated experimental protocol to produce learned aversion behaviour in conservation-working dogs.

Implications: We demonstrated that it is possible to induce a learned aversion to baits in conservation-working dogs, thereby reducing the risk of accidental poisoning.

The mesopredator release hypothesis proposes that when top-down suppression by a larger predator (e.g. dingoes, Canis familiaris) is removed, smaller mesopredators (e.g. feral cats, Felis catus) increase in abundance. Lethal control of dingoes could therefore potentially exacerbate predation pressure by feral cats on smaller prey species. We monitored the activity of dingoes and feral cats (in the absence of red foxes) in two dingo-baited areas over 16 months using 182 camera traps. First, we estimated population densities across each property and found that dingo and feral cat density were unrelated. Second, we compared daily capture rate of dingo and feral cats and found that both predators' capture rates were weakly related to environmental factors and the baiting program. Third, we analysed temporal overlap in activity of these two predators. Although both predators were nocturnal and showed 78.7% overlap in temporal activity patterns, there was a significant difference in activity peaks. Finally, while both predators were distributed across the whole study site, there was strong temporal separation within 1, 12 and 24 h periods at each individual camera. In conclusion, there was no indication of suppression of feral cat population by dingoes. The large and growing body of similar evidence suggests that calls to restrict dingo control on grounds that it will cause mesopredator releases are unsupported and highly unlikely to yield the biodiversity benefits often hoped for by proponents.

The present study was designed to estimate the prevalence of Salmonella contamination in Taiwanese broilers at slaughter and to identify risk factors associated with the presence of Salmonella in processed batches of broilers. Carcass rinse samples from 362 batches of broilers were collected from 45 chicken abattoirs in Taiwan between February 2013 and November 2014. Univariate analyses and multivariable logistic regression analyses were conducted to identify putative risk factors for contamination. Salmonella was detected in 32.6 % (95 % CI: 30.4–34.8) of individual broilers and 56.4 % (95 % CI: 51.1–61.5) of the sampled batches. The multivariable logistic regression model identified season (July to November) (OR = 1.95; 95 % CI: 1.2–3.2) as increasing the risk of infection. Abattoirs in the southern region (Taichung and Kaohsiung) (OR = 0.45; 95 % CI: 0.3−0.8); batches scalded for > 90 s (OR = 0.2; 95 % CI: 0.1−0.3) and batches of commercial white broilers (BR) (OR = 0.21; 95 % CI: 0.1−0.4) all had a decreased risk of contamination compared to abattoirs from the northern region, scalding < 90 s and Taiwan native chickens (TNC), respectively. This study highlights the influence of environmental conditions and poultry breed on the risk of Salmonella contamination of chickens during slaughter.

1. The following study provides the first data on the detection and types of Listeria monocytogenes isolated from broiler chickens during processing and from six Taiwanese abattoir environments. 2. Listeria monocytogenes was not detected in any cloacal (n = 120) or environmental (n = 256) samples collected before and during processing, indicating that faecal material and the environment of abattoirs were not important sources of L. monocytogenes for poultry carcases. However, 28 of 246 (11.4%; 95% CI: 7.7–16.0) rinse samples collected from carcases post-evisceration from three abattoirs were positive for L. monocytogenes. 3. The only serotypes detected were 1/2a (82.1%; 95% CI: 63.1–93.9) and 1/2b (14.3%; 95% CI: 4.0–32.7), with 3.6% (95% CI: 0.1–18.3) non-typable isolates. 4. Characterisation by Pulsed Field Gel Electrophoresis (PFGE) identified five PFGE types, confirming cross-contamination with L. monocytogenes during evisceration, chilling and post-chilling. 5. These findings highlight the potential for cross-contamination to occur through direct contact between carcases, especially whilst in chilling tanks.

Although a nation-wide microbiological screening program of chicken carcasses after chilling in Taiwanese chicken abattoirs has been undertaken since 2006, little is known regarding the potential sources of the Salmonella during the slaughter process. The present study provides data on the detection and serotypes of Salmonella isolated from broilers during processing and from the environment in six abattoirs in Taiwan. Overall, Salmonella were detected in 156 of 622 samples (25.1%; 95% CI: 21.7–28.7) collected. The prevalence of Salmonella varied between sampling sites with 5.8, 17.6, 31.3 and 35.5% of cloacal swabs, environmental samples prior to processing, environmental samples during processing and carcass rinse fluid, respectively, being positive (χ2 = 51.3, p < 0.0001). A total of 15 serotypes were identified from the 156 Salmonella isolates with S. Albany (41.7%) S. Schwarzengrund (20.5%), S. Kentucky (12.8%) and S. Tennessee (5.1%) being the most commonly isolated serotypes. Characterization of 156 isolates by Pulse Field Gel Electrophoresis (PFGE) identified 50 PFGE types. Typing confirmed the presence of the same PFGE type at multiple stages during processing including plucking, evisceration, chilling and post-chilling. The abattoir environment and intestinal contents of chickens are important sources of Salmonella in broiler chicken abattoirs, with the same PFGE types detected at different stages of processing both before and during slaughtering. It is concluded that Salmonella isolates present in the environment and intestinal contents of processed birds survived in the abattoir environment resulting in subsequent carcass contamination along the processing chain including plucking, evisceration, chilling and post-chilling.

Desfosse et al examine the feasibility of using remotely piloted aircraft systems (RPAS) for recreational fishing surveys in Western Australia. Accurate data on recreational fishing activity are required for the sustainable management of many fisheries resources in Western Australia. As such, recreational fishing surveys play a crucial role in providing estimates of participation, fishing effort and recreational catches. A key part of designing recreational fishing surveys involves the selection of the most suitable survey design and data collection tool to match the desired management objective. Recreational fishing surveys should also incorporate probability-based survey designs to enable data collected from a random sample to be expanded to the whole population.