Publications by authors named "Arnould J"

Determining the factors influencing habitat selection and hunting success in top predators is crucial for understanding how these species may respond to environmental changes. For marine top predators, such factors have been documented in pelagic foragers, with habitat use and hunting success being linked to chlorophyll-a concentrations, sea surface temperature and light conditions. In contrast, little is known about the determinants of benthic marine predators.

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Understanding species' critical habitat requirements is crucial for effective conservation and management. However, such information can be challenging to obtain, particularly for highly mobile, wide-ranging species such as cetaceans. In the absence of systematic surveys, alternative economically viable methods are needed, such as the use of data collected from platforms of opportunity, and modelling techniques to predict species distribution in un-surveyed areas.

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Managing feral water buffalo in the Northern Territory is a formidable challenge. As an introduced species, buffalo are associated with a myriad of biosecurity, economic, cultural and environmental issues ranging from overgrazing, decreased water quality, disease vectors to the destruction of cultural assets. Nevertheless, the buffalo are also a harvestable resource that can support economic development of the region.

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Trace elements (TE) in living organisms can have detrimental health impacts depending on their concentration. As many TEs are obtained through diet, trophic niche changes associated with the impacts of anthropogenic activities and climate-change may influence exposure to top predators. The Australian fur seal (Arctocephalus pusillus doriferus; AUFS) represents the greatest resident, marine predator biomass in south-eastern Australia.

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The intracellular pathogens Toxoplasma gondii, Brucella spp., and Chlamydia spp. are all known causative agents of abortion in wildlife.

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Article Synopsis
  • The black-faced cormorant, an Australian seabird, has limited research on its foraging habits and habitat use, which is critical due to concerns over ocean warming in its primary range.
  • The study utilized regurgitated food samples and GPS data loggers to analyze the diet and foraging behavior of these birds while raising chicks from 2020 to 2023 on Notch Island.
  • Results showed that most prey was benthic, with males diving deeper than females, leading to different foraging areas; this sexual segregation may impact species management and reproductive success amidst environmental changes.
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The trade off between energy gained and expended is the foundation of understanding how, why and when animals perform any activity. Based on the concept that animal movements have an energetic cost, accelerometry is increasingly being used to estimate energy expenditure. However, validation of accelerometry as an accurate proxy for field metabolic rate in free-ranging species is limited.

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Investigation of foraging decisions can help understand how animals efficiently gather and exploit food. Prey chase and handling times are important aspects of foraging efficiency, influencing the net energy gain derived from a prey item. However, these metrics are often overlooked in studies of foraging behaviour due to the difficulty in observing them.

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It is challenging to collect robust, long-term datasets to properly monitor the viability and social structure of large, long-lived animals, especially marine mammals. The present study used a unique long-term dataset to investigate the population parameters and social structure of a poorly studied population of bottlenose dolphins (Tursiops sp.) in southern Port Phillip Bay, south-eastern Australia.

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The obligate intracellular bacterial pathogen has been identified in a few species of marine mammals, some of which are showing population declines. It has been hypothesized that in marine mammals is a distinct genotype that varies significantly from the typical terrestrial genotypes. It appears to lack an IS1111.

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Plastic pollution is distributed patchily around the world's oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation.

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Information on resource use and trophic dynamics of marine predators is important for understanding their role in ecosystem functioning and predicting population-level responses to environmental change. Where separate populations experience different local environmental conditions, geographic variability in their foraging ecology is often expected. Within populations, individuals also vary in morphology, physiology, and experience, resulting in specialization in resource use.

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Recently, has been described as a novel pathogen potentially contributing to decreased pup production in Australian fur seals (AusFS, ). Pacific gulls (PGs, ) are known to scavenge AusFS placental material during the fur seal breeding season. It is hypothesized that PGs may act as vectors for this pathogen.

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Past climatic change as a driving force of marine diversification is still largely unclear, particularly for Southern Hemisphere species. Here, we present a case using the brown fur seal, assessing the geographical structure and demographic history using mitochondrial and nuclear data. Results show the two previously defined subspecies (one from Australia and the other from southern Africa) are phylogeographically distinct.

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Bioenergetic approaches are increasingly used to understand how marine mammal populations could be affected by a changing and disturbed aquatic environment. There remain considerable gaps in our knowledge of marine mammal bioenergetics, which hinder the application of bioenergetic studies to inform policy decisions. We conducted a priority-setting exercise to identify high-priority unanswered questions in marine mammal bioenergetics, with an emphasis on questions relevant to conservation and management.

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Quantifying prey characteristics is important for understanding the foraging behaviour of predators, which ultimately influence the structure and function of entire ecosystems. However, information available on prey is often at magnitudes which cannot be used to infer the fine-scale behaviour of predators, especially so in marine environments where direct observation of predator-prey interactions is rarely possible. In the present study, animal-borne video data loggers were used to determine the influence of prey type and patch density on the foraging behaviour of the little penguin (), an important predator in southeastern Australia.

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Effective conservation assessments require detailed information of species' ecological niches during the whole annual cycle. For seabirds, this implies investigating the at-sea distribution and foraging behaviour during both the breeding and non-breeding periods. However, until recently, collecting information about small species has been precluded by the excessive size of the required devices.

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Article Synopsis
  • * This study examines two similar seabird species, the common diving petrel and the South Georgian diving petrel, showing that their resource use changes depending on breeding stages and energy demands, with greater separation during chick-rearing.
  • * Results indicate that the birds not only avoid competition but also show migratory patterns that may reflect their distinct evolutionary histories, emphasizing the need for comprehensive research approaches to understand species co-existence amid environmental changes.
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Knowledge of factors affecting a species' breeding biology is crucial to understanding how environmental variability impacts population trajectories and enables predictions on how species may respond to global change. The Australian fur seal (, AUFS) represents the largest marine predator biomass in southeastern Australia, an oceanic region experiencing rapid warming that will impact the abundance and distribution of prey. The present study (1997-2020) investigated breeding phenology and pup production in AUFS on Kanowna Island, northern Bass Strait.

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Article Synopsis
  • Fur seal populations in the Southern Hemisphere were heavily hunted for their fur in the late 1700s and early 1800s, leading to major ecological impacts that are still unknown today.
  • After a long period of population suppression, Australian fur seals began to recover in the late 1900s, with live pup numbers increasing from about 10,000 per year to 21,400 by 2007.
  • However, a 2013 survey revealed a 20% decline to around 16,500 pups, and further surveys in 2017 indicated a continued decline of 28% at the Seal Rocks colony, suggesting a persistent low population rather than just poor breeding years.
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Fisheries can generate feeding opportunities for large marine predators in the form of discards or accessible catch. How the use of this anthropogenic food may spread as a new behaviour, across individuals within populations over time, is poorly understood. This study used a 16-year (2003-2018) monitoring of two killer whale subantarctic populations ( and at Crozet), and Bayesian multistate capture-mark-recapture models, to assess temporal changes in the number of individuals feeding on fish caught on hooks ('depredation' behaviour) of a fishery started in 1996.

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Knowledge of the factors shaping the foraging behaviour of species is central to understanding their ecosystem role and predicting their response to environmental variability. To maximise survival and reproduction, foraging strategies must balance the costs and benefits related to energy needed to pursue, manipulate, and consume prey with the nutritional reward obtained. While such information is vital for understanding how changes in prey assemblages may affect predators, determining these components is inherently difficult in cryptic predators.

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Stable isotope analyses, particularly of carbon (δ13C) and nitrogen (δ15N), are used to investigate ecological relationships among species. For marine predators, research has shown the main factors influencing their intra-specific and intra-individual isotopic variation are geographical movements and changes in the composition of diet over time. However, as the differences seen may be the result of changes in the prey items consumed, a change in feeding location or the combination of both, knowledge of the temporal and spatial consistency in the isotopic values of prey becomes crucial for making accurate inferences about predator diets.

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The highly dynamic nature of the marine environment can have a substantial influence on the foraging behaviour and spatial distribution of marine predators, particularly in pelagic marine systems. However, knowledge of the susceptibility of benthic marine predators to environmental variability is limited. This study investigated the influence of local-scale environmental conditions and large-scale climate indices on the spatial distribution and habitat use in the benthic foraging Australian fur seal (; AUFS).

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