Academic literature on the topic 'Yellow-eyed penguin'

SUMMARYYellow-eyed penguins (YEPs) have suffered major population declines over the past 30 years, with no single cause established.Leucocytozoonwas first identified in yellow-eyed penguins in 2005. During the 2008/09 breeding season, a high mortality was seen in both mainland yellow-eyed penguins as well as those on Enderby Island of the Auckland Islands archipelago. A high overall prevalence ofLeucocytozoonspp. in association with a high incidence of chick mortality was observed during this period on Enderby Island. One chick had histological evidence of leucocytozoonosis with megaloschizonts in multiple organs throughout its body. In addition, a high prevalence (73·7%) ofLeucocytozoonwas observed by PCR in the blood of adult Enderby yellow-eyed penguins taken during the 2006/07 season. These findings were different from the low prevalence detected by PCR on the coast of the South Island (11%) during the 2008/2009 breeding session and earlier on Campbell Island (21%) during the 2006/2007 breeding session. TheLeucocytozoonspp. sequences detected lead us to conclude that theLeucocytozoonparasite is common 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 aLeucocytozoonspp. that is genetically distinct from that found in other yellow-eyed penguin populations. The role ofLeucocytozoonin the high levels of chick mortality in the yellow-eyed penguins remains unclear.

Emerging viral diseases have become a significant concern due to their potential consequences for animal and environmental health. Over the past few decades, it has become clear that viruses emerging in wildlife may pose a major threat to vulnerable or endangered species. Diphtheritic stomatitis, likely to be caused by an avipoxvirus, has been recognised as a significant cause of mortality for the endangered yellow-eyed penguin (Megadyptes antipodes) in New Zealand. However, the avipoxvirus that infects yellow-eyed penguins has remained uncharacterised. Here, we report the complete genome of a novel avipoxvirus, penguinpox virus 2 (PEPV2), which was derived from a virus isolate obtained from a skin lesion of a yellow-eyed penguin. The PEPV2 genome is 349.8 kbp in length and contains 327 predicted genes; five of these genes were found to be unique, while a further two genes were absent compared to shearwaterpox virus 2 (SWPV2). In comparison with penguinpox virus (PEPV) isolated from an African penguin, there was a lack of conservation within the central region of the genome. Subsequent phylogenetic analyses of the PEPV2 genome positioned it within a distinct subclade comprising the recently isolated avipoxvirus genome sequences from shearwater, canary, and magpie bird species, and demonstrated a high degree of sequence similarity with SWPV2 (96.27%). This is the first reported genome sequence of PEPV2 from a yellow-eyed penguin and will help to track the evolution of avipoxvirus infections in this rare and endangered species.

SummaryHuman disturbance can have behavioural, physiological and population-level consequences on wildlife. Unregulated tourism is having a negative effect on the endangered Yellow-eyed Penguin Megadyptes antipodes on mainland New Zealand. Subantarctic Yellow-eyed Penguins are exposed to tourism on Enderby Island in the Auckland Islands group, 450 km south of New Zealand. Restrictions and guidelines for tourism are in place on Enderby Island, but there has been little study on the efficacy of these. We quantified behavioural responses of the Yellow-eyed Penguin on Enderby Island to human presence by documenting movement patterns and behaviour of penguins in the presence and absence of humans, through both controlled approaches and monitoring penguin behaviour in the presence of tourists. We used these data to model the effective approach distances for reducing disturbance. Human presence caused a significant drop in the probability of a successful transit to or from their nest, and significantly increased the time penguins spent alert and decreased the time spent preening. Modelling showed the distance from a human to a penguin is a significant predictor of the likelihood of a bird displaying disturbance behaviour, with the current minimum approach guideline of 5 m not sufficient for preventing disturbance. Our results indicate that the minimum approach guideline needs to be revised if the probability of disturbance is to be reduced. Modelling the appropriateness of minimum approach guidelines by predicting the probability of disturbance is a useful technique that could be applied to other species and systems. Worldwide, management guidelines need to be scientifically evaluated to ensure efficacy and cater for the more sensitive species affected.

Abstract Context. Diet variability is a significant driver of seabird decline; however, data on seabird diet composition and trends have been affected by changes in precision and resolution owing to the evolution of different sampling methods over time. We investigated the effectiveness of applying a passive molecular diet method using faeces obtained from the endangered yellow-eyed penguin. Aims. To assess the feasibility of applying DNA metabarcoding methods to yellow-eyed penguin faeces to evaluate diet, and to compare the reliability of diet results derived from adults and chicks, and from latrine versus fresh faecal samples. Methods. We collected 313 faecal samples from yellow-eyed penguins resident on the Otago coast of New Zealand from October 2016 to August 2017. We used polymerase chain reaction (PCR) with mitochondrial 16S cephalopod and chordate primers to amplify prey DNA present in the faecal samples, and tested the completeness of our assembled reference databases based on previous diet research. Amplified prey DNA sequences were then assigned to taxa from our reference databases by using QIIME2. Key results. Mitochondrial 16S chordate PCR primers were effective at identifying 29 fish taxa, with 98.3% of amplified sequences being identified to species or genus level in 193 samples (61.7% collected). There was no significant difference in the number, occurrence or proportion of ray-finned fish prey DNA sequences derived from fresh samples or latrines. Mitochondrial 16S cephalopod PCR primers classified 1.98% of amplified DNA sequences as targets, with 96.5% of these target sequences being identified to species or genus level in 48 samples (15.3% collected), and five taxa identified. Conclusions. We recommend the collection of latrine samples to enable long-term monitoring of the diet of yellow-eyed penguins, which will optimise the trade-off between wildlife disturbance and dietary resolution. Further refinement is needed to identify cephalopod dietary components for yellow-eyed penguins, because our cephalopod primers were not as specific as those used for ray-finned fishes, amplifying a large number (>98%) of non-cephalopod species. Implications. DNA metabarcoding offers a robust and comprehensive alternative to other, more intrusive, seabird diet-assessment methods, but still requires parallel studies to provide critical information on prey size, true diet composition and diet quality.

Seabirds have become adapted for foraging in an oceanic environment that can be highly dynamic. Oceanographic processes determine the spatial distribution of seabird prey, while seasonality often has a temporal influence on prey availability. In penguins, these factors are reflected in the different species� foraging strategies. Penguins can broadly be categorized as inshore foragers that live in subtropical to temperate regions and profit from a stable food supply throughout the year close to their breeding sites, and offshore foragers that breed in a pelagic environment at higher latitudes where oceanographic processes and seasonality create much more dynamic, temporally limited prey situations. In this light, offshore foragers can be expected to be much more flexible in their foraging behaviour so as to quickly respond to changes in a dynamic marine environment, while inshore foragers are more likely to exhibit predictable foraging patterns. I examined the foraging ecology of two New Zealand penguin species - the offshore foraging Snares penguin Eudyptes robustus and the inshore foraging Yellow-eyed penguin Megadyptes antipodes and how their foraging strategies reflect an adaptation to the marine environment they exploit. Diet composition of breeding Snares penguins (incubation and early chick-guard) was determined using the water-offloading method. Before the chicks hatched, the penguins generally brought little food back from their long foraging trips. During chick-guard, the stomach contents comprised mainly of crustaceans (~55%), fish (~24%) and cephalopods (~21%). However, the presence at times of many fish otoliths and squid beaks suggests that the latter two prey classes may play an even more important role in the adults� diet than the simple percentages based on mass suggest. The penguins� nesting routines were strongly synchronised between the years and correlated with the onset of the spring planktonic bloom. Using GPS data loggers and dive recorders I found that during the incubation phase, male penguins that performed long (ca. 2 week) foraging trips exhibited a strong affinity to forage in the Subtropical Front some 200 km east of the Snares. At that stage (late mid-October) the front featured elevated chlorophyll a concentrations, a pattern that can be observed every year. Thus, it seems that the front represents a reliable and predictable source of food for the male penguins. After the males returned, the female penguins also performed long foraging trips (<1 week) but never reached the front, primarily because they had to time their return to the hatching of their chicks. After the chicks had hatched, the female Snares penguins were the sole providers of food. At this stage, the penguins performed short foraging trips (1-3 days) and foraged halfway between the Snares and Stewart Island (ca. 70-90 km north of the Snares), where nutrient-rich coastal waters flow eastwards to form the Southland Current. The penguins concentrated their diving effort in these waters, underlining the importance of the warm coastal waters as a food source for breeding Snares penguins. However, diving behaviour between 2003 and 2004 differed with penguins searching for prey at greater depths in the latter year. This underlines the Snares penguins� behavioural flexibility in response to a changing marine environment. The Yellow-eyed penguins as typical inshore foragers showed very consistent foraging patterns at all stages. GPS logger deployments on penguins at Oamaru revealed that the birds foraged almost exclusively at the seafloor and targeted specific areas that featured reefs or epibenthic communities. As a result, the penguins� at-sea movements appeared conservative and at times almost stereotypic. Nevertheless, a comparison of Yellow-eyed penguins breeding on the adjacent Codfish and Stewart islands revealed a degree of plasticity in the species� foraging behaviour. Birds from Codfish Island extended their foraging ranges considerably and switched from primarily bottom to mid-water foraging during the post-guard stage of breeding. It seems likely that this switch is a result of enhanced feeding conditions (e.g. increased prey abundance/quality) in an area further away from the island, but the time required to get there renders this strategy not viable when chicks are small and need to be guarded and fed on a daily basis. As such, the change of behaviour represents a traditional pattern rather than a dynamic response to a sudden change in the marine environment. In comparison, penguins from Stewart Island showed consistent foraging patterns during all stages of breeding. Given the high levels of chick starvation on Stewart Island, the lack of plasticity in foraging behaviour is surprising and might indicate that Yellow-eyed penguins find it difficult to react quickly to a sub-optimal food situation. Overall, it seems that Yellow-eyed penguins show a specialisation for a consistent benthic environment and, thus, lack the behavioural flexibility apparent in Snares penguins, which find their food in a changing pelagic marine environment.

Improving our understanding of the forces driving population decline and the processes that affect the dynamics of threatened populations is central to the success of conservation management. The application of genetic tools, including our ability to examine ancient DNA, has now revolutionised our ability to investigate these processes. The recent human settlement of the Pacific, particularly in New Zealand, provides a unique, accessible system for revealing anthropogenic impacts on native biota. In this thesis I use genetic analyses from modern, historic and subfossil DNA to investigate temporal and spatial genetic structuring of the endangered yellow-eyed penguin (Megadyptes antipodes), and use these analyses to answer questions related to the conservation of this species. The yellow-eyed penguin is endemic to the New Zealand region and currently breeds on the subantarctic Auckland and Campbell Islands and the southeast coast of the South Island. The current total population size is estimated around 6000-7000 individuals, of which more than 60% inhabit the subantarctic. Despite intensive conservation measures by governmental and local community agencies, population sizes have remained highly unstable with strong fluctuations in numbers on the South Island. The species was believed to be more widespread and abundant before human colonisation of New Zealand, thus current management assumed the mainland population to be a declining remnant of a larger prehistoric population. Genetic and morphological analyses of subfossil, historic and modern penguin samples revealed an unexpected pattern of penguin extinction and expansion. Only in the last few hundred years did M. antipodes expand its range from the subantarctic to the New Zealand mainland. This range expansion was apparently facilitated by the extinction of M. antipodes' previously unrecognised sister species, M. waitaha, following Polynesian settlement in New Zealand. The demise of M. waitaha is the only known human-mediated extinction of a penguin species. Despite M. antipodes' recent range expansion, genetic analyses of microsatellite markers reveal two genetically and geographically distinct assemblages: South Island versus subantarctic populations. We detected only two first generation migrants that had dispersed from the subantarctic to the South Island, suggesting a migration rate of less than 2%. Moreover, the South Island population has low genetic variability compared to the subantarctic population. Temporal genetic analyses of historic and modern penguin specimens further revealed that the harmonic mean effective population size of the M. antipodes South Island population is low (<200). These findings suggest that the South Island population was founded by only a small number of individuals, and that subsequent levels of gene flow have remained low. Finally, we present a novel approach to detect errors in historic museum specimen data in cases where a priori suspicion is absent. Museum specimens provide an invaluable resource for biological research, but the scientific value of specimens is compromised by the presence of errors in collection data. Using individual-based genetic analysis of contemporary and historic microsatellite data we detected eight yellow-eyed penguin specimens with what appear to be fraudulently labelled collection locations. This finding suggests errors in locality data may be more common than previously suspected, and serves as a warning to all who use archive specimens to invest time in the verification of specimen data. Overall, yellow-eyed penguins have a remarkable dynamic history of recent expansion, which has resulted in two demographically independent populations. These results reveal that anthropogenic impacts may be far more complex than previously appreciated.

Yellow-eyed penguins have suffered major population declines and periodic mass mortality without an established cause. On Stewart Island a high incidence of regional chick mortality was associated with infection by a novel Leucocytozoon sp. The prevalence, structure and molecular characteristics of this leucocytozoon sp. were examined in the 2006-07 breeding season. In 2006-07, 100% of chicks (n=32) on the Anglem coast of Stewart Island died prior to fledging. Neonates showed poor growth and died acutely at approximately 10 days old. Clinical signs in older chicks up to 108 days included anaemia, loss of body condition, subcutaneous ecchymotic haemorrhages and sudden death. Infected adults on Stewart Island showed no clinical signs and were in good body condition, suggesting adequate food availability and a potential reservoir source of ongoing infections. A polymerase chain reaction (PCR) survey of blood samples from the South Island, Stewart and Codfish Island found Leucocytozoon infection exclusively on Stewart Island. The prevalence of Leucocytozoon infection in yellow-eyed penguin populations from each island ranged from 0-2.8% (South Island), to 0-21.25% (Codfish Island) and 51.6-97.9% (Stewart Island). The high prevalence on Stewart Island represented the infection of 100% of chicks and 83% of adult yellow-eyed penguins when tested by PCR. Sequencing of Leucocytozoon sp. DNA found similarities between infections in yellow-eyed penguin adults and chicks, but differences to Leucocytozoon sp. DNA obtained from Fiordland crested penguins. These findings support the suggestion of cross infection between adults and chicks, and indicate that endemic infection in yellow-eyed penguins is unrelated to that in Fiordland crested penguins. Examination by histology and electron microscopy showed tissue megaloschizonts and circulating round gametocytes. Megaloschizonts up to 440µm diameter showed an affinity for hepatic and splenic tissue and were observed releasing occasional intact cytomeres. Round gametocytes were observed within leucocytes in visceral sections, but not peripheral blood smears. The morphology of Leucocytozoon sp. in yellow-eyed penguins showed similarities to the pathogenic species L. simondi and L. sakharoffi but not L. tawaki. A successful treatment protocol for leucocytozoonosis has not been established, although treatment in a Fiordland crested penguin was able to suppress parasitaemia. The role of Leucocytozoon in yellow-eyed penguins as a cause of morbidity and mortality remains unclear. Further investigation into direct pathogenicity, and the interaction of concurrent disease and environmental influences is required. The findings of this thesis provide potential management recommendations and highlight areas requiring further investigation.