There is much interest in understanding how anthropogenic food resources subsidise carnivore populations. Carcasses of hunter-shot ungulates are a potentially substantial food source for mammalian carnivores. The sambar deer (Rusa unicolor) is a large (≥150 kg) exotic ungulate that can be hunted throughout the year in south-eastern Australia, and hunters are not required to remove or bury carcasses. We investigated how wild dogs/dingoes and their hybrids (Canis lupus familiaris/dingo), red foxes (Vulpes vulpes) and feral cats (Felis catus) utilised sambar deer carcasses during the peak hunting seasons (i.e. winter and spring). We placed carcasses at 1-km intervals along each of six transects that extended 4-km into forest from farm boundaries. Visits to carcasses were monitored using camera traps, and the rate of change in edible biomass estimated at ∼14-day intervals. Wild dogs and foxes fed on 70% and 60% of 30 carcasses, respectively, but feral cats seldom (10%) fed on carcasses. Spatial and temporal patterns of visits to carcasses were consistent with the hypothesis that foxes avoid wild dogs. Wild dog activity peaked at carcasses 2 and 3 km from farms, a likely legacy of wild dog control, whereas fox activity peaked at carcasses 0 and 4 km from farms. Wild dog activity peaked at dawn and dusk, whereas nearly all fox activity occurred after dusk and before dawn. Neither wild dogs nor foxes remained at carcasses for long periods and the amount of feeding activity by either species was a less important predictor of the loss of edible biomass than season. Reasons for the low impacts of wild dogs and foxes on sambar deer carcass biomass include the spatially and temporally unpredictable distribution of carcasses in the landscape, the rapid rate of edible biomass decomposition in warm periods, low wild dog densities and the availability of alternative food resources.

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Context Little is known about wildlife harvesting by licensed recreational hunters in Australia, where both native and introduced species are hunted. It is important to understand harvest trends to assess sustainability for native species and implications for population control of introduced species. Aim The aim of this study was to analyse trends in hunter participation, activity and efficiency, and wildlife harvest, including effects of climate, in Victoria, Australia, for three game species groups: introduced deer, native waterfowl (ducks) and one native grassland species, stubble quail (Coturnix pectoralis). Methods Telephone surveys of a random sample of licenced Victorian hunters were performed annually from 2009 to 2019. Hunters were asked to quantify their hunting effort and the number of animals harvested. The respondents’ answers were analysed to estimate measures of hunter success, activity and efficiency. Bayesian modelling was applied to these data, accounting for changes over time, differences between survey periods for all licence types, and random effects for over-dispersion. The effect of climate on game bird hunter activity and harvest was estimated, as measured by the El Niño-Southern Oscillation (ENSO). Results Over 11 years, annual deer harvest (all species) increased exponentially, at a mean annual rate of 17% (95% credible interval: 14–21%), and the number of deer hunters increased at 8% (5–11%). In contrast, for ducks and stubble quail, hunter numbers remained relatively unchanged, with no evidence of consistent change to total harvests over time, unrelated to changes in environmental conditions or regulations. The annual duck harvest was influenced by ENSO and hunting regulations. The annual stubble quail harvest exhibited ‘boom-and-bust’ dynamics, with an exceptionally large harvest immediately after a La Niña season. Conclusions Long-term monitoring of harvest trends in south-eastern Australia revealed stark differences between introduced deer and native birds: harvest of deer increased rapidly whereas equivalent rates for game birds were either stable or declining. Seasonal effects had a strong influence on game bird harvest. Environmental and regulatory conditions were influential for harvest outcomes for ducks and stubble quail. Implications This study filled a key knowledge gap around managing harvesting of game species, but increased scrutiny is warranted in this field.

Tributary and mainstem connections represent important links for the movement of fish and other biota throughout river networks. We investigated the timing, frequency and environmental conditions associated with movements by adult golden perch (Macquaria ambigua) between the mainstem of the mid-Murray River and a tributary, the Goulburn River, in south-eastern Australia, using acoustic telemetry over four years (2007–2011). Fish were tagged and released in autumn 2007–2009 in the mid-Murray (n = 42) and lower Goulburn (n = 37) rivers within 3–6 km of the mid-Murray-lower Goulburn junction. 38% of tagged fish undertook mainstem–tributary movements, characterised mostly by temporary occupation followed by return of fish to the original capture river. Approximately 10% of tagged fish exhibited longer-term shifts between the mainstem and tributary. Movement of fish from the tributary into the mainstem occurred primarily during the spawning season and in some years coincided with the presence of golden perch eggs/larvae in drift samples in the mainstem. Many of the tributary-to-mainstem movements occurred during or soon after changes in flow. The movements of fish from the mainstem into the tributary were irregular and did not appear to be associated with spawning. The findings show that golden perch moved freely across the mainstem–tributary interface. This demonstrates the need to consider the spatial, behavioural and demographic interdependencies of aquatic fauna across geographic management units such as rivers.

Knowledge of the movement and habitat use of fishes is important in identifying and understanding the causes of population declines and predicting how populations are likely to respond to management interventions. In this study, radiotelemetry was used to examine the spring and summer movement and habitat use patterns of the freshwater catfish (Tandanus tandanus) in a remnant wetland to inform the development of recovery actions for this threatened species. Twenty-one adult fish were tagged and released within Tahbilk Lagoon, a period which coincides with the spawning period for the species. Eleven of the fish were also tracked every 2 h for 68 consecutive hours in December 2009 to examine diel movements. The study revealed that freshwater catfish make extensive use of cover (e.g. wood and macrophytes) and typically have limited ranges (median total linear range and 90% linear range 599 and 173 m respectively), although they occasionally moved more extensively (up to 1.5 km) between floodplain and riverine habitats. Fish moved over much greater areas at night compared with during the day. There was also evidence of sex-specific variation in movement, with a trend for greater movement of female fish at night compared with males. The results of the study suggest that strategies that protect macrophyte and wood habitats and improve connectivity between riverine and floodplain habitats are likely to be important in maintaining and restoring remnant populations of this species.