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Subject: search.filters.subject.Yellow-eyed penguin

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    Total infectome investigation of diphtheritic stomatitis in yellow-eyed penguins (Megadyptes antipodes) reveals a novel and abundant megrivirus.
    (Elsevier B.V., 2023-11-01) Wierenga JR; Grimwood RM; Taylor HS; Hunter S; Argilla LS; Webster T; Lim L; French R; Schultz H; Jorge F; Bostina M; Burga L; Swindells-Wallace P; Holmes EC; McInnes K; Morgan KJ; Geoghegan JL
    First identified in 2002, diphtheritic stomatitis (DS) is a devastating disease affecting yellow-eyed penguins (Megadyptes antipodes, or hoiho in te reo Māori). The disease is associated with oral lesions in chicks and has caused significant morbidity and mortality. DS is widespread among yellow-eyed penguin chicks on mainland New Zealand yet appears to be absent from the subantarctic population. Corynebacterium spp. have previously been suspected as causative agents yet, due to inconsistent cultures and inconclusive pathogenicity, their role in DS is unclear. Herein, we used a metatranscriptomic approach to identify potential causative agents of DS by revealing the presence and abundance of all viruses, bacteria, fungi and protozoa - together, the infectome. Oral and cloacal swab samples were collected from presymptomatic, symptomatic and recovered chicks along with a control group of healthy adults. Two novel viruses from the Picornaviridae were identified, one of which - yellow-eyed penguin megrivirus - was highly abundant in chicks irrespective of health status but not detected in healthy adults. Tissue from biopsied oral lesions also tested positive for the novel megrivirus upon PCR. We found no overall clustering among bacteria, protozoa and fungi communities at the genus level across samples, although Paraclostridium bifermentans was significantly more abundant in oral microbiota of symptomatic chicks compared to other groups. The detection of a novel and highly abundant megrivirus has sparked a new line of inquiry to investigate its potential association with DS.
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    A novel gyrovirus is abundant in yellow-eyed penguin (Megadyptes antipodes) chicks with a fatal respiratory disease.
    (2023-02) Wierenga JR; Morgan KJ; Hunter S; Taylor HS; Argilla LS; Webster T; Dubrulle J; Jorge F; Bostina M; Burga L; Holmes EC; McInnes K; Geoghegan JL
    Yellow-eyed penguins (Megadyptes antipodes), or hoiho in te reo Māori, are predicted to become extinct on mainland Aotearoa New Zealand in the next few decades, with infectious disease a significant contributor to their decline. A recent disease phenomenon termed respiratory distress syndrome (RDS) causing lung pathology has been identified in very young chicks. To date, no causative pathogens for RDS have been identified. In 2020 and 2021, the number of chick deaths from suspected RDS increased four- and five-fold, respectively, causing mass mortality with an estimated mortality rate of >90%. We aimed to identify possible pathogens responsible for RDS disease impacting these critically endangered yellow-eyed penguins. Total RNA was extracted from tissue samples collected during post-mortem of 43 dead chicks and subject to metatranscriptomic sequencing and histological examination. From these data we identified a novel and highly abundant gyrovirus (Anelloviridae) in 80% of tissue samples. This virus was most closely related to Gyrovirus 8 discovered in a diseased seabird, while other members of the genus Gyrovirus include Chicken anaemia virus, which causes severe disease in juvenile chickens. No other exogenous viral transcripts were identified in these tissues. Due to the high relative abundance of viral reads and its high prevalence in diseased animals, it is likely that this novel gyrovirus is associated with RDS in yellow-eyed penguin chicks.
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    Population ecology and foraging behaviour of yellow-eyed penguins in New Zealand’s subantarctic Auckland Islands : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science and Ecology, Massey University, Manawatū, New Zealand
    (Massey University, 2022) Muller, Christopher
    Penguins and other seabirds rely on healthy, functioning marine systems, and are vulnerable to human-induced changes. Accurate long-term monitoring of a threatened species’ population size and trend is therefore important for conservation management. The endangered yellow-eyed penguin (Megadyptes antipodes) is found only in New Zealand waters, with separate northern (mainland New Zealand and offshore islands) and southern (subantarctic) breeding populations. The northern population is declining, believed to be due to threats at sea including direct mortality, as well as changes to food supply, and the effects of climate change. The southern population was previously estimated to comprise at least 60% of the species. Despite this, the subantarctic has been little studied, with one previous population estimate at the Auckland Islands in 1989, two at Campbell Island, and no recent data or measurement of population trends. To address this data gap, this research studied the population and foraging behaviour (diving, foraging location, and diet) of breeding yellow-eyed penguins on Enderby Island, Auckland Islands, from 2015–2017. The first step for this research was locating cryptic yellow-eyed penguin nests hidden in thick vegetation, as ground searches are inefficient, time-consuming, and potentially hazardous for researchers in subantarctic terrain. I utilised a drone fitted with a novel multi-frequency VHF receiver which located nests in only 3% of the time for traditional search methods, facilitating my other research. Next, I defined methods for surveying populations in the subantarctic, and estimated a mean of 577 breeding pairs at the Auckland Islands, although the population and number of breeders fluctuated annually, and may have declined since 1989. My foraging research showed that 62% of foraging trips, and over 86% of all southern yellow-eyed penguin dives were pelagic (mid-water), unlike the predominantly benthic (seabed) dives of the northern population. Maximum dive depth was 134 m for benthic dives, and 115 m for pelagic dives, which is deeper than many northern penguins dive. The proportion of pelagic dives increased during La Niña years, likely influenced by climate conditions and prey availability. Foraging distance also varied, with a maximum distance of 47 km from shore, further than many northern birds travel. Foraging area size was greater for females and for pelagic foragers, although benthic foragers travelled further from shore on average. Diet also varied, and during El Niño conditions comprised lower trophic level prey, which were more benthic, and found closer to shore than during La Niña years. Diet results showed some individuals maintained consistent foraging behaviour, although foraging plasticity was also evident. Some individuals changed their foraging behaviour between years, and even within a breeding season. Variable breeding success in the subantarctic, along with variable foraging behaviour and diet suggests that prey availability is likely limiting the southern population in some years. Prey availability is therefore expected to be a major influence on survival and breeding success in the future, particularly if the effects of climate change become more pronounced.
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    Impacts of human disturbance stimuli on the behaviour and breeding biology of Subantarctic Yellow-eyed Penguins (Megadyptes antipodes) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Palmerston North, New Zealand
    (Massey University, 2018) French, Rebecca Kay
    Eco-tourism is increasing in popularity worldwide, particularly in previously isolated areas such as Antarctica and the subantarctic. This may be increasing the levels of human disturbance stimuli (human-related presence, objects or sounds), which can have impacts on wildlife at an individual level (behaviourally and physiologically) and at a population level. Human disturbance (the response of an animal to a disturbance stimulus) has been studied in most penguin species, showing both inter- and intra-specific differences in responses to disturbance stimuli at similar distances. The Yellow-eyed Penguin (Megadyptes antipodes) is negatively impacted by human disturbance stimuli, but very little research of any kind has been conducted on the subantarctic population. This is despite some areas within the subantarctic being regularly exposed to tourism, and the subantarctic population making up an estimated 60% of the entire species. I used an experimental approach to investigate the behavioural impacts of human disturbance stimuli on subantarctic Yellow-eyed Penguins, on Enderby Island. Human presence significantly changed their behaviour, resulting in an increased time spent vigilant and a decrease in the frequency of maintenance behaviours. By modelling the probability of disturbance at varying distances from the penguin to the human, I showed the current minimum approach distance of 5 m (with a 99% chance of disturbance) was not effective. I also quantified the breeding biology of subantarctic Yellow-eyed Penguins, and investigated the impact of human disturbance stimuli on their breeding success. There was no difference in nesting success (expressed as number of eggs, chicks and fledglings surviving per pair) between the disturbed and undisturbed site and no significant difference in the average weight and body size of fledglings at the disturbed site compared to fledglings at the undisturbed site. My results indicate that at current levels human disturbance stimuli has a behavioural impact on subantarctic Yellow-eyed Penguins, but a population-level impact was not detectable. This may be due to the low level of tourism and high degree of tourism management in the New Zealand subantarctic, and the resulting low number of interactions between penguins and humans. Enderby Island tourism may therefore be an example of sustainable eco-tourism and successful management, although more research including multi-year studies would be needed to confirm this.
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    An investigation of the causes of mortality in yellow-eyed penguins (Megadyptes antipodes) across their range with specific emphasis on the role played by Leucocytozoon : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science in Wildlife Health at Massey University, Palmerston North, New Zealand
    (Massey University, 2015) Argilla, Lisa Shelley
    Over the past 40 years, there have been frequent mass mortality events documented in yellow-eyed penguins (Megadyptes antipodes). In most cases, these mortality events have resulted in significant adult or chick mortality resulting in a population decline. Previous studies in yellow-eyed penguin mortality have been attributed to events such as unidentified phytotoxins, starvation, poor nutrition, climatic events and infectious causes. However, the full impact of these factors on yellow-eyed penguin population decline and mortality events is not well understood. During the Austral summer of 2008/09, there were mortality events documented in both the subantarctic and mainland yellow-eyed penguin populations with different patterns of mortality and different factors associated with the mortality between both locations. A high overall prevalence of Leucocytozoon spp. in association with a high incidence of chick mortality was observed during this period on Enderby Island. Despite its endemic nature in this population, statistical analysis demonstrated that infection with Leucocytozoon did not play a significant role in mass mortality of Enderby Island chicks, other than as a cause of sporadic individual mortality. The Leucocytozoon spp. sequences detected lead to the conclusion that the Leucocytozoon parasite is endemic in yellow-eyed penguins and has a higher prevalence in penguins from Enderby Island than those from Campbell Island and the mainland of New Zealand. The Enderby Island yellow-eyed penguins are infected with a Leucocytozoon spp. that is genetically distinct from that found in other yellow-eyed penguin populations. The role of Leucocytozoon in the high levels of chick mortality in the yellow-eyed penguins remains unclear. A very low mortality was observed in the Catlins population despite there being a high level of human impact at some nest regions within this location. A high level of mortality was described in the Otago Peninsula population with this population affected by high human disturbance from tourism, reduced quality of breeding habitat, diphtheritic stomatitis as well as increased environmental temperatures during the study season. All of these factors played a significant role in mortality of chicks at this location. Results from this research provide the foundation for future investigations into the risk factors for mortality in yellow-eyed penguins across their range as well as providing a basis for sound management and veterinary advice to assist with conservation of this endangered species.