Belinda Cannell

Rising global temperatures will have profound impacts on species and ecosystem functioning. Species existing near their thermal thresholds will be particularly vulnerable to these changes, and those species that rely on, or preferentially use, artificial structures may face pronounced effects. Gaining insights into the anticipated climate changes, both present and future, is crucial for informing conservation practices and the utilisation of artificial structures in conservation efforts. Using three years of data, we quantified and compared temperature of artificial nest boxes installed between 1986 and 2006 and natural nest burrows of a fringing population of little penguins existing at the northwestern limit of their range. Nest boxes were ineffective at replicating conditions of natural nests, exhibiting consistently higher daily maximum temperature (~ 2˚C) and exceeded upper thermoneutral limits for longer than natural nests. Fine scale biotic and abiotic nest characteristics influenced maximum nest temperature and time exposed to temperatures ≥ 35˚C. Simulated temperature increase of 2˚C predicted an increase in the number of days exceeding thermally stressful conditions (≥ 35°C) by up to 49%. Such increases will expose penguins to potentially fatal thermal conditions, particularly during the late breeding and moulting phases of their annual cycle. This study revealed that current and future thermal environments of little penguin terrestrial habitat on Penguin Island can exceed physiological limits for this species. Intervention to improve artificial nests and better quantify consequences is urgently needed given recent estimates of a declining population and increasing risk of local extinction.

The fixation index, F IS , has been a staple measure to detect selection, or departures from random mating in populations. However, current Next Generation Sequencing (NGS) cannot easily estimate F IS , in multi‐locus gene families that contain multiple loci having similar or identical arrays of variant sequences of ≥1 kilobase (kb), which differ at multiple positions. In these families, high‐quality short‐read NGS data typically identify variants, but not the genomic location, which is required to calculate F IS (based on locus‐specific observed and expected heterozygosity). Thus, to assess assortative mating, or selection on heterozygotes, from NGS of multi‐locus gene families, we need a method that does not require knowledge of which variants are alleles at which locus in the genome. We developed such a method. Like F IS , our novel measure, 1 H IS , is based on the principle that positive assortative mating, or selection against heterozygotes, and some other processes reduce within‐individual variability relative to the population. We demonstrate high accuracy of 1 H IS on a wide range of simulated scenarios and two datasets from natural populations of penguins and dolphins. 1 H IS is important because multi‐locus gene families are often involved in assortative mating or selection on heterozygotes. 1 H IS is particularly useful for multi‐locus gene families, such as toll‐like receptors, the major histocompatibility complex in animals, homeobox genes in fungi and self‐incompatibility genes in plants.

Significant marine heatwaves (MHWs) developed along the Western Australian coast in 1999 and 2011. Despite ecosystem losses and the southwards occurrence of many tropical fish species during and after the extreme MHW in 2011, there have been few studies on the effects of this MHW on seabirds, and no biological impacts related to the 1999 MHW have been reported. Using data from 1986-2019, we investigated the impacts of these events on breeding outcomes, body condition, diet composition, population size and mortality of little penguins on Penguin Island, in the temperate waters off Western Australia. Breeding outcomes were negatively impacted by the MHWs but body condition was not. Diet composition changed after the MHW, with sandy sprat Hyperlophus vittatus , the penguins’ typical major prey component, replaced by scaly mackerel Sardinella lemuru , a tropical fish species. Using an open robust design analysis that accounts for imperfect capture probabilities and staggered annual arrival and departure dates, we found that the population decreased by 80% following the 2011 MHW. Finally, more penguins died from starvation or from novel protozoal parasitic infections in 2011 and 2012 that were potentially introduced with the changed diet. This research highlights that the temporal and spatial influence of MHWs on seabirds depends on several factors. Furthermore, the magnitude and direction of a prey species’ response can be very localised and have significant impacts on avian predators. There are no obvious ways to mediate climate effects, but perhaps measures taken to reduce any synergistic impacts on prey abundance, particularly during MHW events, could be effective.

Routine post mortems of deceased penguins from Penguin Island, Western Australia, found that a temporal cluster of cases presented with characteristic gross and microscopic changes, namely birds in good body condition with hepatomegaly and splenomegaly, multifocal hepatic and splenic necrosis and numerous, 1–2 μm diameter protozoan parasites within the necrotic foci. Electron microscopy identified the protozoa as belonging to the phylum Apicomplexa. Molecular investigations by PCR gave inconsistent results. PCR performed by an external laboratory identified a novel Haemoproteus spp. organism in samples from 4 of 10 cases from this group, while PCR at Murdoch University identified Toxoplasma gondii in 12 of 13 cases (including 9 of the 10 assayed at the external laboratory). Immunohistochemistry of formalin fixed tissues also identified Toxoplasma in the hepatic and splenic lesions. The distinctive mortalities which were observed in this group of penguins are attributed to a fulminant toxoplasmosis, with a concurrent Haemoproteus infection in some cases. Though the clinical signs of infection are unknown, the gross and microscopic appearance at post mortem is sufficiently characteristic to allow a diagnosis to be made on these features. Definitive confirmation of Toxoplasma infection can be made by immunohistochemistry or PCR.

Climate change and other human activities are causing profound effects on marine ecosystem productivity. We show that the breeding success of seabirds is tracking hemispheric differences in ocean warming and human impacts, with the strongest effects on fish-eating, surface-foraging species in the north. Hemispheric asymmetry suggests the need for ocean management at hemispheric scales. For the north, tactical, climate-based recovery plans for forage fish resources are needed to recover seabird breeding productivity. In the south, lower-magnitude change in seabird productivity presents opportunities for strategic management approaches such as large marine protected areas to sustain food webs and maintain predator productivity. Global monitoring of seabird productivity enables the detection of ecosystem change in remote regions and contributes to our understanding of marine climate impacts on ecosystems.

The most western little penguin colony globally, and the most northern in Western Australia (WA) is found on Penguin Island, WA. The penguins use coastal bays that are also used extensively by recreational watercraft. These penguins have been found to either dive predominantly to shallow depths of 1–5 m or to depths >8 m. It is thus hypothesized that (a) both the shallow and deeper diving penguins can potentially be disturbed or injured by these watercraft but that the risk will differ between the two diving strategies, and (b) that risk of injury for both is greater during the summer and autumn, when people are more likely to use watercraft. This was tested by attaching data loggers to little penguins during chick rearing and by investigating necropsy records. Diving activity was studied for the very shallow and relatively deeper diving penguins separately, and we considered the penguins were vulnerable to interactions with watercraft when they were within the top 2 m of the water column or at the surface. Shallow‐diving penguins executed >1,200 dives per day, 64% of dives occurred within the top 2 m, and they were vulnerable for approximately two‐thirds of their time at sea. The deeper diving penguins executed fewer dives. Almost half of dives were to ≥10 m, yet they were vulnerable for almost one‐third of their time at sea. Their post‐dive recovery was also longer. Thus, the risk of interaction from watercraft differs depending on the diving behaviour. This study highlights the potential impact to little penguins throughout Australia and New Zealand.

Context. Demographic parameters in wildlife populations are typically estimated by monitoring a limited number of individuals in observable sites and assuming that these are representative of the whole population. If individuals permanently disperse to unobservable breeding sites, recruitment and immature survival are expected to be negatively biased and breeding-site fidelity cannot be investigated. Aims. To develop a method to obtain unbiased estimated of survival, recruitment and breeding dispersal when individuals can move to, or recruit in, unobservable sites. Methods. We used the flexibility of multi-event capture-recapture models to estimate dispersal and recruitment to unobservable sites, merging observations made at two sites within the same breeding locations. We illustrated the model with data on little penguin (Eudyptula minor) breeding in artificial as well as in natural nests. Natural nests are unknown or inaccessible and birds in these sites remain unobservable. Encounters at beaches surrounding the colony suggested that marked animals can permanently move to unobservable nests. We built the multi-event model considering two possible states of the individuals (alive breeding in a nest box and alive in a natural nest) and three types of observations (encountered at a nest only, encountered at the beach only and encountered at both places). This model ensured that the breeding dispersal to unobservable places became estimable. Key results. Results indicate that the estimated survival was 8% higher than when recaptures at artificial nests were analysed alone. Also, fidelity to artificial nests was 12% lower than to natural nests. This might reflect the greater availability of natural sites or, alternatively, a heterogeneity between these two types of nest. Conclusions. We obtained an estimate of local survival of little penguins breeding at Penguin Island that incorporates the permanent migration to unobservable sites and found an asymmetric dispersion towards natural nests. Implication. Our conclusions suggest a need for more careful treatment of data derived from artificial sites alone, as demographic parameters might be underestimated if animals prefer natural breeding sites or if they are in greater proportion compared with artificial ones. The analytical approach presented can be applied to many biological systems, when animals might move into inaccessible or unobservable breeding sites.

Penguins both forage and travel in the marine environment and so spend a much greater proportion of their lives in this environment than other seabirds. This maximises their exposure to an increasing range of threats compared with other seabirds. From late 2003 to 2012, necropsies were performed on 159 Little Penguins found in the Perth region, Western Australia. Given the close proximity of the colonies to increasingly populated urban areas, the aims of this study were to: (1) determine the causes of mortality; (2) determine the proportion of deaths attributable to anthropogenic causes; (3) use this information to help guide management strategies; and (4) identify potential threats to coastal seabirds in general. In most cases, cause of mortality could be assigned to one of 11 categories. Trauma, most likely from watercraft, was the main cause of mortality. The next most common cause, starvation, was more likely to occur in spring and summer. Management strategies for colonies of Little Penguins near high levels of watercraft activity should take into account the risk of injury or death from watercraft strikes.

One hundred and thirty four Little Penguin (Eudyptula minor) carcases found since 2004 in south west Australia were necropsied. The livers and spleens from ten of the penguins exhibited varying degrees of multifocal, randomly scattered areas of necrosis and varying numbers of parasites were associated with these areas. Hepatomegaly and splenomegaly were noted in many of these ten cases. Necrosis and parasites were also observed in the cardiac muscle of four of the cases and in the lung tissue in one of the penguins. Using PCR, the parasites were positively identified in four of the cases as Haemoproteus spp. and morphologically identical tissue stage parasites associated with histopathological changes were observed in all ten dead penguins. This is the first study to demonstrate both the in situ presence of the Haemoproteus parasite in any member of the Sphensicidae family and mortality due to its presence. We postulate the involvement of anomalous environmental conditions in a potential increase in local vectors.