A commercial roadkill Virtual Fence (VF) mitigation device (iPTE Traffic Solutions) was used in a field trial to test its effectiveness, for which previously published results have been inconsistent, along a 4.9 km segment of road on Bruny Island, Tasmania. A total of 585 days of monitoring roadkill by species was conducted, with six sections that were alternatively switched on or off according to the Crossover and Multiple Before–After–Control–Impact (MBACI) experimental designs that divided monitoring into “off–on” then “on–off” periods. Aggregate counts, for each period by section combination, from daily counts of Tasmanian pademelons (Thylogale billardierii) were modelled, with a total count of 222. The statistical analysis used the MBACI design to estimate the VF effect using a log-odds ratio parameter (LORP) while accounting for local spatio-temporal effects. Both versions of the analysis, either averaged over the three spatial replicates (paired sections) or two temporal replicates (blocks), showed no statistically significant effect of the VF, judged as an LORP estimate not sufficiently below zero. Corresponding percentage reduction estimates of 9% and 16% were derived from the LORP. The corresponding statistical power required to detect a nominal significant reduction of 50% in rate was 0.5 and 0.6, respectively. This study confirms the results from a similar previous field trial in southern Tasmania that this VF is likely to lead to, if anything, only a minor reduction in roadkill.

Aims: Two methods of calibrating regression models of inter-moult period (IMP) as a function of temperature exposure (T) for crustaceans, in particular, Antarctic krill (Euphausia superba) are reviewed in terms of both theoretical and empirical properties in order to make recommendations on the application of the methods and/or the use of the resultant fitted models. Methodology: The method and fitted model that used a meta-analysis of published results from laboratory-reared krill using means of directly observed IMP for a range of controlled, constant temperature regimes has valid theoretical and empirical support. The alternative used moult frequencies obtained as a “byproduct” of 5-d Instantaneous Growth Rate (IGR) experiments carried out at sea for which individual IMPs were not directly observed. Instead mean IMP given T and animal total length (L) was predicted using the moult frequencies disaggregated to binary data of moulted versus not-moulted as dependent variable in the calibration of a logistic regression on T and L. The shape of the daily development rate, R, the inverse of IMP, versus T response curve fitted using direct observations is a classical monotonically increasing curve whereas for combinations of sex/maturity classes the curves fitted using indirect observations are parabola-like with sexually dimorphic concavities of either up or down. Four sources of bias in predictions of mean IMP using the indirect observations and estimation method are described. One source due to an unrepresentative sampling frame can lead to large positive bias in estimated mean IMP based on theory which has been absent until now and that applies a discrete uniform distribution for next moult date corresponding to ideal asynchrony. This bias and that due to IGR experimental measurement error in T cannot be remedied. Conclusion: The indirect method and the corresponding fitted models are unreliable and should not be used.

Scientific observer programs are often the only means to estimate the total number and circumstances of interactions (including the life status at the time of the interaction) between commercial fisheries and threatened, endangered and protected species (TEPS). However, without estimating the precision of predefined sampling fractions, the accuracy of estimates are often poorly understood. We present a methodology to estimate appropriate sampling fractions using historical observer data from the New South Wales (Australia) ocean trap and line fishery, and implement an on-board monitoring program to estimate contemporary rates of interactions with TEPS in the fishery to evaluate the effectiveness of management measures implemented to reduce interactions. A total of 327 fishing trips (similar to 61,150 hook deployments) were sampled over 31 months with a single observed interaction each with the critically endangered grey nurse shark (Carcharius taurus) and scalloped hammerhead (Sphyrna lewini) recorded along with the capture of six seabirds. Observed catches included 97 species (70 finfish, 23 elasmobranchs, 1 invertebrate and 3 birds), of which 74 and 57 species were retained and discarded, respectively. Current fishing practices, combined with declines is reported effort targeting 'large sharks' following management reform, spatial protection measures, and gear regulations, were found to be minimising interactions between the main fishing method and TEPS. However, regular monitoring and research may be required to continually assess the effectiveness of mitigation strategies. The logic and methodology for determining appropriate sample fractions using existing data before implementing on-board sampling is relevant to the monitoring of other commercial fisheries.

Despite research and public scrutiny over recent decades, discarding continues to be an issue for trawl fisheries. Previous research demonstrates that environmental, biological, operational, legislative and socioeconomic drivers affect a fisher's decision to discard an organism. Therefore, the reduction of fishery discards requires a better understanding of fishery-specific drivers. Despite considerable research and mitigation, further work is required to reduce discarding to acceptable levels (currently ~ 50% in Australia). To better understand the drivers of discarding, this study used a modelling approach to determine environmental and operational factors that drive discarding in the New South Wales (NSW) ocean prawn trawl fishery (OPT). Further, the study investigated the relationship between the discarded number of individuals from all functional species groups (i.e. elasmobranchs, crustaceans and fish combined) and the retained catch weight. This model was also run on just fish partly due to their disproportionally high contribution to the discard assemblage (e.g. 76% of all species or higher taxon) and importance (e.g. to the ecosystem and fisheries). The results quantified relationships of environmental and operational drivers of discarding and the relationship of fish discarding and retained catch weight was found to be linear. However, the identified relationships appear complicated and, whilst an important first step, more work is required to identify all drivers influencing discarding practices. We, in combination with previous research, suggest implementation of effort quotas may be a suitable management initiative to reduce discarding and its impact; at least whilst more research is conducted to better understand this complex process. Furthering our understanding of discarding is urgent given its global impact and the rate of discarding in the OPT.

Aims: Evaluation of the effectiveness of methods of roadkill mitigation requires field experiments and thus experimental designs. We evaluated such a published experiment that used a virtual road-fence (VF) system to attempt to reduce roadkill of bare-nosed wombats (Vombatus ursinus) and draw general conclusions on the ability of the implemented design, given overall mean rates of roadkill, to detect a substantial reduction of 50%. Study Design: The study site consisted of contiguous fenced and unfenced road sections that were each monitored for road kill for 995 and 322 days pre- and post-installation, respectively. The study design was an unreplicated BACI (Before-After-Control-Impact) design. Methodology: No statistical analysis of the roadkill data were carried out in the original study. We used a Poisson/log-link Generalized Linear Model fit to their BACI data as a single 2x2 table of counts and define a single interaction parameter as a function of control-adjusted rate reduction due to the VF. This parameter can also be defined as the logarithm of the ratio of odds of a random kill in the fenced section occurring in the post-installation period to the corresponding odds for the unfenced section. A null hypothesis of no effect of the VF corresponds to a log odds-ratio of zero. We use simulation to show that estimates of this parameter have close to a Gaussian distribution and from this derive an estimate of the statistical power of the design to detect a hypothetical effect of a 50% reduction in rate. We also used simulation to estimate the corresponding power to detect this reduction if the BACI had been physically replicated three times. Results: The estimated log odds-ratio and the corresponding percent reduction inferred for the VF were -0.02 (SE=0.53) and 1.8%, respectively, and the statistical power of the design to detect a hypothetical effect of a 50% reduction in rate was only .35 but gave an improved power of .7 under the hypothetical replication. Conclusion: Our results showed that there was very low confidence in this design combined with similar overall roadkill rates being able to detect a 50% reduction. This increased to medium-to-high confidence if the experiment had been replicated in three locations. The very small point estimate of reduction could have been so low compared to a true but modest effect purely by chance, thus our conclusion is that there is very low confidence in any estimate of the VF’s effect obtained using this study’s design in the context of common roadkill rates.

Abstract Context Dogs are increasingly being used in conservation work to collect information on species abundance, distribution, occupancy and other biological measures. Monitoring feral cats through the use of detection dogs could provide a useful technique to complement existing feral cat survey and control methods. Aim To demonstrate and quantify the ability of trained detection dogs to reliably and efficiently detect feral cat scats when present in woodland conservation reserves in the Wheatbelt of Western Australia. Methods Cat scats were randomly placed into 466 1.5 ha (150 m × 100 m) quadrats in Tutanning Nature Reserve, Western Australia, and the location of the scat was recorded. Quadrats were then independently searched by dogs walking a central transect line and the locations of all scats detected were recorded, with the distance from the scat to the transect subsequently being calculated. Data collected allowed the relationship between distance from the transect and detection probability to be used to assist modelling of detection probabilities. Key results Dogs detected scats in 213 (55%) of 384 quadrats that were searched using a single transect line method. All indications of a find by the detector dogs were associated with a cat scat (no false indications). Detection probabilities for scats declined with distance from the transect line and with an increasing age of the scat. Simulations to investigate management options for cat control programs quantified effort required to detect cat scats under varying densities. Conclusion Dogs were highly efficient at detecting scats within the woodland environment of the Western Australian wheatbelt. The effort required to detect a scat was considerably higher when cat density was low. Implications On the basis of the detection probabilities derived from the present study, trained scat-detection dogs can be expected to efficiently search woodlands and find cat scats by using an effective sweep width of 100 m (50 m either side of a transect) when scats are fresh. Sweep widths need to be reduced significantly if it is important to locate scats that have been exposed to the elements for greater periods of time, or to search habitats where terrain and vegetation cover are more challenging.

Two recent attempts to model the long-term trend in mean density of Antarctic krill in the southwestern sector of the Atlantic using the KRILLBASE dataset using different statistical methods as well as inclusion versus exclusion of data from “non-scientific” nets have resulted in disparate conclusions. The approach that used a linear mixed model (LMM) fitted to the log of mean density, after standardisation was applied to individual net hauls and with means calculated for 12 spatial strata by years between 1976 and 2016, gave a highly statistically significant linear “regional” decline north of 60oS and, to a lesser degree, south of this latitude. The alternative approach that used a ”hurdle” model fitted to the individual net haul data, excluded regional stratification, and excluded non-scientific nets failed to detect an overall significant decline. The method of modelling log transformed means was reappraised and corrected by applying a meta-analytic LMM approach. Additionally, nonlinear smooths in year by region and a smooth in mean “climatological temperature” were included in the LMM. This model showed on average a mostly consistent decline north of 60oS, however, neither trend was significantly different from a no-trend prediction with the trend north of 60oS highly uncertain. Uncertainty of predictions resulted in only weak power to detect a substantial decline of the order of 70% between 1985 and 2005. These model-based inferences neither strongly support nor reject a general hypothesis that there has been a dramatic decline in density of Antarctic krill in the Southwest Atlantic over this period.

Seabirds are declining on a global scale, and this trend is concerning as they play an important role in the marine ecosystem. The decline is due to multiple reasons, but harvest fisheries are a major contributor. The impact of fisheries, however, appears to vary; demersal trawlers cause mortality of many birds in some areas and very few in others. Fishery-dependent monitoring is required to understand this impact on seabirds, and particularly to better understand the variable impact of demersal trawling. We employed a targeted observer program to gather data on seabird assemblages, catastrophic interactions with trawl vessels and predictors of vessel attendance by the seabirds. The latter is a useful proxy for catastrophic interactions and provides information on potential mitigation. Throughout the program period, 1040942 seabirds from ~21 species attended New South Wales (NSW) ocean demersal trawlers. These species included 7 species of petrel and albatross listed by the IUCN, including the flesh footed shearwater Ardenna carneipes and wandering albatross Diomedea exulans. Two catastrophic interactions were recorded, and intrinsic and extrinsic predictors of vessel attendance (e.g. offal discharge and wind, respectively) were characterised. The results of the study will provide information to managers, with the goal of ensuring the sustainability of NSW ocean trawling—in particular its coexistence with threatened seabirds. The NSW Ocean Trawl fishery appears to directly harm very few seabirds which is not always the case when considering worldwide trawl fisheries. Predictors of attendance such as space, time and offal discharge can potentially be used to mitigate the attractiveness of trawlers to seabirds.

Many children experience anxiety but have limited access to empirically-supported interventions. School-based interventions using brief, computer-assisted training provide a viable way of reaching children. Recent evidence suggests that computer-delivered ‘positive search training’ (PST) reduces anxiety in children. This multi-informant, randomised controlled trial compared classroom-based, computer-delivered PST (N = 116) to a classroom-based, therapist-delivered cognitive-behavioural intervention (CBI) (N = 127) and a curriculum-as-usual control condition (CAU) (N = 60) in 7–11 year old children. Primary outcomes were child and parent report of child anxiety symptoms. Secondary outcomes were child and parent report of child depressive symptoms and child attention biases. Outcomes were assessed before and after the interventions, and six- and 12-months post-intervention. Teacher report of children’s social-emotional functioning was assessed at pre- and post-intervention. As expected, compared to CAU, children receiving PST and the CBI reported greater anxiety reductions by post-intervention and six-month follow-up but, unexpectedly, not at 12-month follow-up. Partially consistent with hypotheses, compared to CAU, parents reported greater anxiety reductions in children receiving PST, but not the CBI, at 12-month follow-up. Contrary to expectation, there was a pre- to post-intervention increase in threat attention bias in PST compared to the other conditions, with no significant differences at follow-up. In support of hypotheses, teachers reported higher post-intervention social-emotional functioning in Year 5 students receiving the CBI but, unexpectedly, lower post-intervention functioning in students receiving PST. There were no effects on depressive symptoms. Further research is needed on strategies to maintain long-term benefits and determine preventative versus early intervention effects.

A commentary by Hill et al. (2019) raised some questions concerning the analyses of trends in krill density presented in Cox et al. (2018). We have re-examined our analyses and conclude that our approach does not contain multiple errors as asserted by Hill et al. (2019). Specifically, we reiterate that our statistical analysis of the publicly available version of KRILLBASE does not support the notion of a precipitous decline in krill density between 1976 and 2016. We respond to the technical criticisms made by Hill et al. (2019) of our work. We include a section where we suggest some approaches to help build consensus on detecting ecological trends in the Southern Ocean in the future. These approaches include: integrated assessments incorporating all relevant data, utilising data that will become available in the future from emerging technologies, and suggestions of other potential population monitoring methods that may be effective for krill.

Adjustment for spatial and temporal trends using a Generalised Additive Model with Poisson error also failed to detect a significant VF effect. A simulation study used to estimate the power to detect a statistically significant reduction in roadkill rate gave, for median estimates of reduction of 21%, 48%, and 57%, estimates of power of 0.24, 0.78, and 0.91, respectively. Therefore, this study failed to confirm previously reported estimates of reduction in roadkill rates claimed for this VF of 50%-90%, despite having adequate power to do so. However, point estimates obtained for these three species of reductions ranging from 13% to 32% leave open the question of there being a real but modest effect that was below statistical detection limits.

For many decades pelagic longline fisheries have been responsible for the deaths of large numbers of seabirds worldwide. Baited hooks deployed onto the sea surface attract seabirds to fishing vessels leading to attacks on baits, capture and death by drowning. An alternative is to deploy baits underwater where they are less detectable, more difficult to reach and less likely to be taken by seabirds. In 2010 and 2012 proof-of-concept experiments were conducted in the Uruguayan pelagic longline fishery with a newly developed device designed to set baits underwater. The experiments examined the differences between setting baits at the sea surface and setting baits underwater with regard to the abundances of seabirds following the vessel, incidences of attacks on baits and mortality. Underwater setting led to marked reductions in the numbers of seabirds following the fishing vessel and attacks on baits, the behavioural precursors to mortality. Mortality rates of seabirds on baits set to the relatively shallow depth of 4 m were 87% lower than on baits set at the surface. No seabirds were caught on baits released 10 m underwater, a reduction of 100% compared to the surface setting mortality of 11.6 birds/1000 hooks. No differences were detected between the two setting methods in the catch rates of target and non-target fish species. The evidence from the experiments, combined with the known dive depths of the white chinned petrel (Procellaria aequinoctialis), a deep diving, difficult-to-deter species, suggests that baits released 10 m underwater could reduce the incidental mortality of albatrosses and petrels to negligible levels.

The Antarctic marine environment is changing, and changes in the Southwest Atlantic sector have included decreases in sea ice and increases in water temperature. Associated with these changes is a reported 38% and 81% per decade decline in the numerical density (hereafter density) of Antarctic krill Euphausia superba Dana, 1850, between 1976 and 2003. Few changes in other components of the ecosystem that could be attributed to such a change, such as a mass decline in krill-dependent predators, have been detected. In an ecosystem so dependent on this keystone species, a massive population decline in krill ought to have had an obvious effect. In the absence of such an effect, it is timely to revisit the issue of the purported decline in krill density. The original analysis that indicated a decline in krill density was based on the 2004 version of KRILLBASE, a database of net samples. We analysed the publicly available and updated version (version 1, accessed 30 November 2017) and our analyses did not suggest a significant decline in krill density. Rather, after accounting for sampling heterogeneity and habitat variables, average krill density appears to have been stable but with considerable inter-annual variability. Since our results were unable to find any evidence for a decline in krill density we recommend a re-appraisal of many of the paradigms that underlie much of the recent thinking about ecosystem change Antarctic waters. Such a revision is necessary to provide a firmer foundation for predictions of the effects of climate change and resource extraction on the Southern Ocean ecosystem.

There is convincing evidence of the transmission of anxiety and depression from parents to children; however, mechanisms by which this vulnerability is passed on are unclear. Cognitive models and a small body of cross-sectional research suggest that parental attention biases (ABs) may be one mechanism involved in transmission. Longitudinal associations of maternal and offspring ABs with offspring symptoms have been scarcely studied. Forty-three mothers-child dyads were included. All children (7-12 years old) were diagnosis-free while 24 mothers had a lifetime emotional disorder (anxiety or depression) (high risk, HR) and 19 mothers had no psychiatric diagnoses (low risk, LR). This study examined cross-sectional and longitudinal associations of maternal and child AB and child anxiety symptomology at initial and 12-month assessments. ABs were assessed using a visual-probe task with emotional faces. There was a significant cross-sectional but not longitudinal association of increased child anxiety symptoms with increased maternal threat AB for HR but not LR dyads. At the cross-sectional level, increases in HR but not LR offspring anxiety symptomology were associated with maternal threat AB. Larger longitudinal studies are required that examine the interplay between parent-child variables and include multiple time-points of assessment and measures of AB.

Fire is a major ecological process in ecosystems globally. Its impacts on fauna can be both direct (e.g., mortality) and indirect (e.g., altered habitat), resulting in population recovery being driven by several possible mechanisms. Separating direct from indirect impacts of fire on faunal population recovery can be valuable in guiding management of biodiversity in fire-prone environments. However, resolving the influence of direct and indirect processes remains a key challenge because many processes affecting fauna can change concomitantly with time since fire. We explore the mechanisms influencing bird response to fire by posing the question, can temporal changes in vegetation structure predict changes in bird occurrence on sites, and can these be separated from other temporal changes using the surrogate of time since fire? We conducted a 12-yr study of bird and vegetation responses to fire at 124 sites across six vegetation classes in Booderee National Park, Australia. Approximately half of these sites, established in 2002, were burned by a large (>3000 ha) wildfire in 2003. To disentangle collinear effects of temporal changes in vegetation and direct demographic effects on population recovery that are subsumed by time since fire, we incorporated both longitudinal and cross-sectional vegetation effects in addition to time since fire within logistic structural equation models. We identified temporal changes in vegetation structure and richness of plant and bird species that characterized burned and unburned sites in all vegetation classes. For nine bird species, a significant component of the year trend was driven by temporal trends in one of three vegetation variables (number of understory or midstory plant species, or midstory cover). By contrast, we could not separate temporal effects between time since fire and vegetation attributes for bird species richness, reporting rate, and the occurrence of 11 other bird species. Our findings help identify species for which indirect effects of vegetation dominate recovery and thus may benefit from vegetation management where conservation actions are required and, conversely, those species for which direct effects of time since fire drive recovery, where simply leaving a system to recover following the last disturbance will be sufficient.

Three species of skate, Bathyraja eatonii, B. irrasa and B. murrayi, are commonly taken as incidental by catch in Patagonian toothfish (Dissostichus eleginoides) longline and trawl fisheries, and the mackerel icefish (Champsocephalus gunnari) trawl fishery on the Kerguelen Plateau (KP) in the southern Indian Ocean. Data from fishery observations for 1997-2014 shows that the three skates were widely distributed across the Kerguelen Plateau, showing different spatial distributions, linked mainly with depth. Off Heard Island and McDonald Islands (HIMI), in the southern part of the KP, B. eatonii and B. irrasa were most abundant to the north and northwest of Heard Island, out to the edge of the Australian Exclusive Economic Zone (EEZ), and were caught down to depths of 1790 m and 2059 m respectively. The smallest species, B. murrayi, occurred mainly in the shallower waters down to 550 m, and was most abundant to the north and northeast, close to Heard Island. Around Kerguelen Islands, in the northern part of the KP, skates were most abundant between the 500 m and 1000 m contours circling and extending from the islands.Catch rates were modelled using zero-inflated GAMS and GLMs. The catch rates of skates from the trawl fisheries in the Australian EEZ surrounding Heard Island and McDonald Islands have shown little evidence of depletion on the main trawl fishing grounds, although there is evidence of a decrease in the average total length of B. eatonii. The marine reserves and the conservation measures employed by the Commission for the Conservation of Antarctic Marine Living Resources in the HIMI fisheries, appear to provide effective protection for the skates, at least in the shallower waters where the trawl fisheries operate. B. irrasa taken in the deeper waters where longline fishing occurs have shown a slight decline in catch rate over the years of the HIMI fishery. Although all skates are returned to the water from this fishery, survival rates are unknown and careful monitoring should continue to assess the status of these stocks. There appears to be little change in the abundance of the skate species at Kerguelen in the time period.This study provides the first review of skate by-catch across both the HIMI and Kerguelen fisheries. Ongoing monitoring of species specific by-catch levels and further research to determine the important life history parameters of these species are required, particularly for B. irrasa which is taken in both trawl and longline fisheries. Crown Copyright (C) 2016 Published by Elsevier B.V. All rights reserved.

A method for combining a proportional-hazards survival time model with a bioassay model where the log-hazard function is modelled as a linear or smoothing spline function of log-concentration combined with a smoothing spline function of time is described. The combined model is fitted to mortality numbers, resulting from survival times that are grouped due to a common set of observation times, using Generalized Additive Models (GAMs). The GAM fits mortalities as conditional binomials using an approximation to the log of the integral of the hazard function and is implemented using freely-available, general software for fitting GAMs. Extensions of the GAM are described to allow random effects to be fitted and to allow for time-varying concentrations by replacing time with a calibrated cumulative exposure variable with calibration parameter estimated using profile likelihood. The models are demonstrated using data from a studies of a marine and a, previously published, freshwater taxa. The marine study involved two replicate bioassays of the effect of zinc exposure on survival of an Antarctic amphipod, Orchomenella pinguides . The other example modelled survival of the daphnid, Daphnia magna , exposed to potassium dichromate and was fitted by both the GAM and the process-based DEBtox model. The GAM fitted with a cubic regression spline in time gave a 61 % improvement in fit to the daphnid data compared to DEBtox due to a non-monotonic hazard function. A simulation study using each of these hazard functions as operating models demonstrated that the GAM is overall more accurate in recovering lethal concentration values across the range of forms of the underlying hazard function compared to DEBtox and standard multiple endpoint probit analyses.