Neophoca Cinerea Research Articles

Assessment of the status and trends in abundance of a coastal pinniped, the Australian sea lion Neophoca cinerea

Australian sea lions Neophoca cinerea are endemic to Australia, with their contemporary distribution restricted to South Australia (SA) and Western Australia (WA). Monitoring of the species has proved challenging due to prolonged breeding events that occur non-annually and asynchronously across their range. The most recent available data from 80 extant breeding sites (48 in SA, 32 in WA) enabled us to estimate the species-wide pup abundance to be 2739, with 82% (2246) in SA and 18% (493) in WA, mostly based on surveys conducted between 2014 and 2019. We evaluated 1776 individual site-surveys undertaken between 1970 and 2019 and identified admissible time-series data from 30 breeding sites, which revealed that pup abundance declined on average by 2.0% yr-1 (range 9.9% decline to 1.7% growth yr-1). The overall reduction in pup abundance over 3 generations (42.3 yr) was estimated to be 64%, with over 98% of Monte Carlo simulations producing a decline >50% over a 3-generation period, providing strong evidence that the species meets IUCN ‘Endangered’ criteria (decline ≥50% and ≤80%). The population is much smaller than previously estimated and is declining. There is a strong cline in regional abundances (increasing from west to east), with marked within-region heterogeneity in breeding site pup abundances and trends. Results from this study should improve consistency in the assessment of the species and create greater certainty among stakeholders about its conservation status. To facilitate species management and recovery, we prioritise key data gaps and identify factors to improve population monitoring.

Design of Deployment Strategies to Monitor the Movement of Animals with Passive Electronic Devices.

Current animal monitoring systems have improved our knowledge of quantitative animal ecology. There are many electronic tracking technologies such as VHF/UHF telemetry, light-level geolocation, ARGOS satellite telemetry and GPS tracking. To reach the desired level of information retrieval requires the planning of adequate equipment effort and coverage, which depends on the properties of the system. We propose an equipment arrangement model consisting of a given number of receiver stations in a two-dimensional space in which the animals move according to a central place movement model. The objective is to characterize how the transmission of tracking data depends on the movement of the animals and the design of the equipment deployment: quantity and location of the receiver stations and their associated reception radius. We also implement the model using real trajectories of southern elephant seals and Australian sea lions publicly available online and tracked during the years 2010–2012. We characterize the data transmission based on different equipment configurations and we obtained analogous results to the theoretical model.

Cytokine RT-qPCR and ddPCR for immunological investigations of the endangered Australian sea lion (Neophoca cinerea) and other mammals.

Measurement of cytokine gene expression by reverse transcription quantitative polymerase chain reaction (RT-qPCR) is used widely to assess the immune system of animals and to identify biomarkers of disease, but its application is limited in wildlife species due to a lack of species-specific reagents. The free-ranging endangered Australian sea lion (Neophoca cinerea) experiences significant clinical disease and high pup mortality due to intestinal hookworm infection. Developing immunological tools specific to the species will aid in the assessment of drivers of disease and its impact in population demographics. This study describes the development and validation of cross-reactive RT-qPCR assays to measure five important cytokines involved in innate and Th1/Th2 responses (IL-6, TNFα, IFNγ, IL-4 and IL-10) in unstimulated blood samples from a range of different mammalian species including the Australian sea lion. All RT-qPCR assays efficiencies ranged between 87% (Ovis aries TNFα) and 111% (Bos taurus IL-10) and had strong linearity (R2). IL-4 and IFNγ gene expression for N. cinerea fell below the dynamic range (and therefore quantifiable limits) of RT-qPCR assays but were able to be quantified using the novel droplet digital PCR (ddPCR). This study delivers new immunological tools for eco-immunologists studying cytokine gene expression in wildlife species and is to our knowledge, the first cytokine ddPCR approach to be reported in a pinniped species.

Diversity and Distribution of Escherichia coli in Three Species of Free-Ranging Australian Pinniped Pups

Anthropogenic activities and pollution are impacting marine environments globally. This has resulted in increasing numbers of human-associated phylotypes of Escherichia coli, an indicator of faecal contamination, being found in both aquatic environments and upper trophic marine mammals that are considered sentinels for marine health. The objective of this study was to determine the presence and diversity of E. coli in pups of three species of free-ranging pinnipeds in Australia. Faecal samples (n = 964) were collected between 2016 and 2019 from Australian sea lion (Neophoca cinerea), Australian fur seal (Arctocephalus pusillus doriferus) and long-nosed fur seal (Arctocephalus forsteri) pups from eight breeding colonies extending along the Southern Australian coast. E. coli were isolated from 842 (87.3%) samples and molecular screening was applied to assign isolates to E. coli phylotypes and sub-types. The human associated E. coli phylotype B2 was the most frequently isolated in all species at seven of the eight colonies, with 73.7% of all E. coli isolates belonging to this phylotype. Phylotype distribution did not differ significantly within or across species, breeding colonies or breeding seasons. Further analysis of B2 isolates into sub-types showed a significant difference in sub-type distribution across breeding seasons at two colonies (Seal Rocks and Cape Gantheaume). The predominance of the B2 phylotype could indicate that all colonies are exposed to similar levels of anthropogenic pollution. This widespread occurrence of the human-associated E. coli phylotypes highlights the imperative for ongoing monitoring and surveillance of microbes in both the marine environment and sentinel species.

Morphological Grouping and Body Mass Prediction Models

Every facet of an organism’s function is affected by its body size, such as heart rate, metabolism, organ size and function, feeding ecology, and locomotion. Using body size to assess the function and size of organs in extant mammals is relatively easy. However, estimating the body size and organ function of transitional fossil species, such as the Eocene whales, is difficult. The Eocene whales are diverse in body size, structure, and habitat, therefore a single allometric model will not provide the most accurate body size estimation for each fossil whale family and therefore less accurate organ function assessment. The goal of my research is to predict the body size of the Eocene whales using morphological models of extant mammals as guides. The first stage is the morphological grouping and body mass prediction models using modern mammal skeletons.I measured the skull, vertebrae, and appendicular bones of multiple species of modern aquatic, semi‐aquatic, and terrestrial mammals. I calculated an average body mass representative of each species using recorded body weights. Using Principal Component Analysis (PCA), I determined morphological groupings for these mammals from the skeletal measurements. For each PCA analysis completed, I created a linear regression equation to predict body size from the skeletal variables used in each analysis and the calculated average body sizes. I tested these prediction models using the measurements from 12 representative skeletons that were not included in the data set used to create the model, specifically Odocoileus virginianus, Tragulus napu, Hippopotamus amphibus, Tapirus indicus, Sus scrofa, Canis lupus lycaon, Nyctereutes procyonid, Ehydra lutris, Gulo gulo, Neophoca cinerea, Lobodon carinophagus, and Ursus maritimus.From the PCA, I identified five morphological groups for the mammals selected: Aquatic, Semi‐aquatic, Semi‐terrestrial, Large Terrestrial and Small Terrestrial. For the prediction model using all skeletal variables, the standard error of the estimate (SEE) for all 12 test individuals ranged from 0.3359 – 0.7496. For the skull variables, the SEE ranged from 0.1260 – 0.3197. For the limb variables, the SEE ranged from 0.1716 – 0.3964. For the vertebral variables, the SEE ranged from 0.1511 – 0.2851. These small SEE values and the large sample size substantiate the accuracy of these predictive models and the reliability of their respective confidence intervals (CI) and prediction intervals (PI) for the models. The results confirm that these linear regression models will be appropriate to predict the body mass of the Eocene whales in the second stage of this project.Support or Funding InformationKent State University; East Tennessee State University; Sigma Xi

Rapid condition monitoring of an endangered marine vertebrate using precise, non-invasive morphometrics

Understanding causes of population change is critical for conservation. Quantifying these causes can be difficult, especially for hard to sample animals like marine vertebrates (e.g. pinnipeds). One solution is to investigate spatiotemporal differences in a species' body condition by measuring body size and mass. Collecting traditional morphological measurements is risky and labour intensive, making less invasive and more efficient techniques desirable. Using Australian sea lions (Neophoca cinerea) of known size and mass as a case study, we tested the suitability of using drone-derived photogrammetry to estimate morphological measurements and assess body condition. Drone-derived measurements were precise and without bias. Animal mass was highly correlated with the 2-dimensional and 3-dimensional measurements of simplified area and volume, explaining >77% and >84% (all P < .01) of the variation in mass, depending on the age-sex class. The juvenile class exhibited the strongest associations (both 2D and 3D R2 > 0.99). Using each measurement as a proxy for mass, we calculated body condition indices for each class by standardising the variables by animal length. Photogrammetric indices ranked individuals comparably to those generated from ground-collected data (rs = 0.77–1, depending on age-sex class). Our technique provides a workflow for the non-invasive collection of morphometric data to quantify animal condition, which is transferrable to other pinniped species with species-specific calibration. It will also facilitate the efficient collection of morphometric data of vertebrates from remotely sensed imagery.

Chemical fingerprints suggest direct familiarisation rather than phenotype matching during olfactory recognition in Australian sea lions (Neophoca cinerea)

Olfaction is one of the most commonly used senses for communication among animals and is of particular importance to mother-offspring recognition in mammals. The use of smell in offspring recognition has been well studied, however, we often lack information about the underlying mechanistic basis for olfactory recognition. Using gas chromatography–mass spectrometry (GC–MS), we examine chemical profiles of two different colonies of Australian sea lions (Neophoca cinerea) and assess similarity of chemical fingerprints in mother-pup pairs. This analysis allows us to examine whether a chemical base for phenotype matching exists in this species. Our results showed no GC-detectible mother-offspring similarity in the overall chemical fingerprints, suggesting that direct familiarisation is a more likely mechanism used by Australian sea lion mothers for recognition of their young. Our analysis also demonstrates that colony differences are encoded within chemical fingerprints and appear to be highly influenced by environmental compounds. The study improves our understanding of how Australian sea lion females use odours for selective offspring recognition and the potential importance of environmentally acquired chemical compounds in the overall odour bouquet used in mother-pup interactions.

Chemical Profiles of Integumentary and Glandular Substrates in Australian Sea Lion Pups (Neophoca cinerea).

Recognition of individuals or classes of individuals plays an important role in the communication systems of many mammals. The ability of otariid (i.e., fur seal and sea lion) females to locate and identify their offspring in colonies after returning from regular foraging trips is essential to successful pup rearing. It has been shown that olfaction is used to confirm the identity of the pup by the mother when they reunite, yet the processes by which this chemical recognition occurs remain unclear. Using gas chromatography-mass spectrometry, we examined chemical profiles of integumentary and glandular secretions/excretions from pre- and post-molt Australian sea lion pups (Neophoca cinerea) and compared fur and swab samples to assess data collection methods. Multivariate statistics were applied to assess differences in chemical composition between body regions and sexes. We found differences among secretions from various body regions, driven by the distinctiveness of the oral odor mixture. The fine-scale trends in pre- and post-molt pups seem to differ due to changes in the behavior of pups and consequent decrease in the transfer of compounds among adjacent body regions in older pups. Volatile compounds from exocrine substrates were not distinct for different sexes. We also show that swab samples provide better data for exploring social olfaction than fur samples for this species. Obtaining fundamental chemical information, in this case chemical profiles of animals, and discerning differences in chemical composition is an important step toward fully exploring the intricacies of mother-offspring olfactory recognition and its underlying processes.

Multimodal mother–offspring recognition: the relative importance of sensory cues in a colonial mammal

Animals often employ multiple sensory modalities for communication and recognition; however, the combination of sensory cues used by individuals in given contexts will vary. Although mother–offspring recognition has been widely investigated and is known to be a multimodal process in gregarious mammal species, there is a dearth of information about the interactions between various sensory cues. Here we show how acoustic, olfactory and visual cues are used in a synergistic way in Australian sea lion, Neophoca cinerea, mother–offspring recognition. We interpret the results using a cost–benefit perspective to disentangle the evolutionary pressures on each component of this communication system. Although olfactory cues can convey individual identity information it was their presence, not their congruency, that prompted female sniffs. We found that calls needed to be from the female's own pup for the identification process to be successful, with the information encoded in acoustic cues overriding that of olfactory cues. Despite each sensory cue accurately conveying identity information when presented in isolation, in a multimodal setting their importance, function or role may change and seems to be driven by the costs and benefits of obtaining information resulting from the constraints imposed by the active space of cues.

Morphometrical and molecular evidence suggests cryptic diversity among hookworms (Nematoda: Uncinaria) that parasitize pinnipeds from the south-eastern Pacific coasts

Hookworms of the genus Uncinaria parasitize pinniped pups in various locations worldwide. Four species have been described, two of which parasitize pinniped pups in the southern hemisphere: Uncinaria hamiltoni parasitizes Otaria flavescens and Arctocephalus australis from the South American coast, and Uncinaria sanguinis parasitizes Neophoca cinerea from the Australian coast. However, their geographical ranges and host specificity are unknown. Uncinaria spp. are morphologically similar, but molecular analyses have allowed the recognition of new species in the genus Uncinaria. We used nuclear genetic markers (internal transcribed spacer (ITS) and large subunit (LSU) rDNA) and a mitochondrial genetic marker (cytochrome c oxidase subunit I (COI)) to evaluate the phylogenetic relationships of Uncinaria spp. parasitizing A. australis and O. flavescens from South American coasts (Atlantic and Pacific coasts). We compared our sequences with published Uncinaria sequences. A Generalized Mixed Yule Coalescent (GMYC) analysis was also used to delimit species, and principal component analysis was used to compare morphometry among Uncinaria specimens. Parasites were sampled from A. australis from Peru (12°S), southern Chile (42°S), and the Uruguayan coast, and from O. flavescens from northern Chile (24°S) and the Uruguayan coast. Morphometric differences were observed between Uncinaria specimens from both South American coasts and between Uncinaria specimens from A. australis in Peru and southern Chile. Phylogenetic and GMYC analyses suggest that south-eastern Pacific otariid species harbour U. hamiltoni and an undescribed putative species of Uncinaria. However, more samples from A. australis and O. flavescens are necessary to understand the phylogenetic patterns of Uncinaria spp. across the South Pacific.

Visual cues do not enhance sea lion pups\u2019 response to multimodal maternal cues

Mammals use multiple sensory cues for mother-offspring recognition. While the role of single sensory cues has been well studied, we lack information about how multiple cues produced by mothers are integrated by their offspring. Knowing that Australian sea lion (Neophoca cinerea) pups recognise their mother’s calls, we first tested whether visual cues are used by pups to discriminate between conspecifics of different age classes (adult female vs pup). We then examined if adding a visual stimulus to an acoustic cue enhances vocal responsiveness of Australian sea lion pups, by presenting wild individuals with either a visual cue (female 3D-model), an acoustic cue (mother’s call), or both simultaneously, and observing their reaction. We showed that visual cues can be used by pups to distinguish adult females from other individuals, however we found no enhancement effect of these cues on the response in a multimodal scenario. Audio-only cues prompted a similar reaction to audio-visual cues that was significantly stronger than pup response to visual-only cues. Our results suggest that visual cues are dominated by acoustic cues and that pups rely on the latter in mother recognition.

Comparative ecology of Escherichia coli in endangered Australian sea lion (Neophoca cinerea) pups

The dissemination of human-associated bacteria into the marine environment has the potential to expose wildlife populations to atypical microbes that can alter the composition of the gut microbiome or act as pathogens. The objective of the study was to determine whether endangered Australian sea lion (Neophoca cinerea) pups from two South Australian colonies, Seal Bay, Kangaroo Island and Dangerous Reef, Spencer Gulf, have been colonised by human-associated Escherichia coli. Faecal samples (n = 111) were collected to isolate E. coli, and molecular screening was applied to assign E. coli isolates (n = 94) to phylotypes and detect class 1 integrons; mobile genetic elements that confer resistance to antimicrobial agents. E. coli phylotype distribution and frequency differed significantly between colonies with phylotypes B2 and D being the most abundant at Seal Bay, Kangaroo Island (55% and 7%) and Dangerous Reef, Spencer Gulf (36% and 49%), respectively. This study reports the first case of antimicrobial resistant E. coli in free-ranging Australian sea lions through the identification of class 1 integrons from an individual pup at Seal Bay. A significant relationship between phylotype and total white cell count (WCC) was identified, with significantly higher WCC seen in pups with human-associated phylotypes at Dangerous Reef. The difference in phylotype distribution and presence of human-associated E. coli suggests that proximity to human populations can influence sea lion gut microbiota. The identification of antimicrobial resistance in a free-ranging pinniped population provides crucial information concerning anthropogenic influences in the marine environment.

Geographic vocal variation and perceptual discrimination abilities in male Australian sea lions.

Vocal characteristics can vary among and within populations. In species with geographic variation in the structure of vocalizations, individuals may have the ability to discriminate between calls from local and non-local individuals. The ability to distinguish differences in acoustic signals is likely to have a significant influence on the outcome of social interactions between individuals, including potentially mate selection and breeding success. Pinnipeds (seals, fur seals, sea lions and walruses) are highly vocal yet the Australian sea lion (Neophoca cinerea) is the only eared seal known to show geographic vocal variation in male barks. Barks are produced in many social interactions and encode sufficient information for both individual and colony identity to be discriminable. Yet until now, whether males could themselves discriminate these bark differences was unclear. We performed playback experiments in four breeding colonies to investigate whether males can discriminate local from non-local barks. Overall, males responded more strongly to barks from their own colony compared to barks from other colonies regardless of whether those other colonies were close or distant. Competition for females is high in Australian sea lions, but mating periods are asynchronous across colonies. The ability to correctly assess whether a male is from the same colony, thus representing a potential competitor for mates, or merely a visitor from elsewhere, may influence how males interact with others. Given the high cost of fighting, the ability to discern competitors may influence the nature of male-male interactions and ultimately influence how they allocate reproductive effort.

Setting a course for marine mammal research in Western Australia

Given limited funding and increasing pressures on our natural resources it is becoming ever more critical that science be directed at improving our understanding and management of priority issues. This relies on dialogue and alignment between researchers and managers to ensure that appropriate questions are asked and the answers incorporated in robust and transparent decision-making processes which should include relevant evidence-based science. We used a prioritisation framework as a tool to bring managers and scientists together to discuss and agree on current priorities for research on marine mammals in Western Australia, including posing relevant questions. Eight species were identified as high priorities for fundamental research, including three dolphin species (Australian humpback, snubfin and common dolphin), three baleen whale species (Antarctic and pygmy blue and dwarf minke whale), the Australian sea lion and the dugong. The pressures we evaluated resulted in a priority need for research to better understand and mitigate impacts across a range of species, including noise pollution from shipping and vessel activity, climate change and fishing by-catch. Scientists and managers agreed on a set of topics and associated research questions for the high-priority species that would best inform ongoing conservation and management of marine mammals in Western Australia and that would have broad applicability nationally and globally. We provide an example of how these priorities can be used to develop a research program with targeted funding. Overall, this process has demonstrated the value of bringing scientists and managers together with a tool that allows them to jointly determine priorities and research questions.

The role of visual cues in mother-pup reunions in a colonially breeding mammal.

Parental care is an important factor influencing offspring survival and adult reproductive success in many vertebrates. Parent-offspring recognition ensures care is only directed to filial young, avoiding the costs of misallocated resource transfer. It is essential in colonial mammal species, such as otariids (fur seals and sea lions), in which repeated mother-offspring separations increase the risk of misdirecting maternal effort. Identification of otariid pups by mothers is known to be multi-modal, yet the role of visual cues in this process remains uncertain. We used three-dimensional visual models to investigate the importance of visual cues in maternal recognition of pups in Australian sea lions (Neophoca cinerea). We showed that the colour pattern of pup pelage in the absence of any other sensory cues served to attract the attention of females and prompt investigation. Furthermore, females were capable of accurately distinguishing between models imitating the age-class of their own pup and those resembling older or younger age-classes. Our results suggest that visual cues facilitate age-class discrimination of pups by females and so are likely to play an important role in mother-pup reunions and recognition in otariid species.

Fur seals and sea lions (family Otariidae) on the breakwaters at Adelaide

Long-nosed fur seals (Arctocephalus forsteri) and Australian sea lions (Neophoca cinerea) on the breakwaters at the mouth of the Port River estuary at Adelaide’s Outer Harbor were counted from 2004 to 2015. Observed counts were modelled using a generalised linear model. Fur seal numbers have been increasing since 2011; for sea lions there was a small discernible annual trend in counts. Counts of fur seals varied seasonally; most annual maxima were in August or September with modelled peak numbers around 9–11 September. The maximum count of fur seals was 79 in September 2015. For sea lions, the model predicts annual peaks in the period 28 August to 19 September. The maximum count of sea lions was nine in September 2009. The haulout sites on the Outer Harbor breakwaters are easily accessible by boats, including pleasure craft. In particular, the seaward end of the outer breakwater is a popular spot with recreational anglers whose lines are often within a few metres of the seals. We propose that a management plan should be developed involving a study of the effect of boat approaches on seals utilising the Outer Harbor area followed by education coupled with enforcement.

DNA metabarcoding for diet analysis and biodiversity: A case study using the endangered Australian sea lion (Neophoca cinerea).

The analysis of apex predator diet has the ability to deliver valuable insights into ecosystem health, and the potential impacts a predator might have on commercially relevant species. The Australian sea lion (Neophoca cinerea) is an endemic apex predator and one of the world's most endangered pinnipeds. Given that prey availability is vital to the survival of top predators, this study set out to understand what dietary information DNA metabarcoding could yield from 36 sea lion scats collected across 1,500 km of its distribution in southwest Western Australia. A combination of PCR assays were designed to target a variety of potential sea lion prey, including mammals, fish, crustaceans, cephalopods, and birds. Over 1.2 million metabarcodes identified six classes from three phyla, together representing over 80 taxa. The results confirm that the Australian sea lion is a wide‐ranging opportunistic predator that consumes an array of mainly demersal fauna. Further, the important commercial species Sepioteuthis australis (southern calamari squid) and Panulirus cygnus (western rock lobster) were detected, but were present in <25% of samples. Some of the taxa identified, such as fish, sharks and rays, clarify previous knowledge of sea lion prey, and some, such as eel taxa and two gastropod species, represent new dietary insights. Even with modest sample sizes, a spatial analysis of taxa and operational taxonomic units found within the scat shows significant differences in diet between many of the sample locations and identifies the primary taxa that are driving this variance. This study provides new insights into the diet of this endangered predator and confirms the efficacy of DNA metabarcoding of scat as a noninvasive tool to more broadly define regional biodiversity.

Anthropogenic threat assessment of marine-associated fauna in Spencer Gulf, South Australia

Assessing the vulnerability of species to [anthropogenic threats is an essential step when developing management strategies for wild populations. With industrial development forecasted to increase in Spencer Gulf, South Australia, it is crucial to assess the ongoing effects of anthropogenic threats to resident and migratory species. Expert elicitation was used to assess 27 threats against 38 threatened, protected, and iconic marine-associated species. Species and threat interactions were assessed individually, and as taxonomic or functional groups. Climate change had the greatest overall exposure (c.f. risk) across species, followed by disturbance, pollution, disease/invasive species, and fishing/aquaculture threats. The largest overall sensitivities (c.f. consequences) were pollution and disease/invasive species, followed by climate change, disturbance and fishing/aquaculture threats. Vulnerability scores (exposure x sensitivity) showed the climate change group posing the greatest overall threat in Spencer Gulf, with individual climatic threats ranking as three of the top four biggest threats to most animal groups. Noise, shipping, and net fishing were considered the greatest region-specific individual threats to marine mammals; as were trawl fishing, line fishing, and coastal activities to fish/cuttlefish; trawl fishing, line fishing, and net fishing to elasmobranchs; and oil spill, disease, and coastal activities to sea/shorebirds. Eighteen of the 20 highest vulnerability scores involved the short-beaked common dolphin, Indo-Pacific bottlenose dolphin, and Australian sea lion, highlighting the particular susceptibility of these species to specific threats. These findings provide a synthesis of key threats and vulnerable species, and give management a basis to direct future monitoring and threat mitigation efforts in the region.

Intrinsic and extrinsic influences on standard metabolic rates of three species of Australian otariid.

The study of marine mammal energetics can shed light on how these animals might adapt to changing environments. Their physiological potential to adapt will be influenced by extrinsic factors, such as temperature, and by intrinsic factors, such as sex and reproduction. We measured the standard metabolic rate (SMR) of males and females of three Australian otariid species (two Australian fur seals, three New Zealand fur seals and seven Australian sea lions). Mean SMR ranged from 0.47 to 1.05 l O2 min-1, which when adjusted for mass was from 5.33 to 7.44 ml O2 min-1 kg-1. We found that Australian sea lion mass-specific SMR (sSMR; in millilitres of oxygen per minute per kilogram) varied little in response to time of year or moult, but was significantly influenced by sex and water temperature. Likewise, sSMR of Australian and New Zealand fur seals was also influenced by sex and water temperature, but also by time of year (pre-moult, moult or post-moult). During the moult, fur seals had significantly higher sSMR than at other times of the year, whereas there was no discernible effect of moult for sea lions. For both groups, females had higher sSMR than males, but sea lions and fur seals showed different responses to changes in water temperature. The sSMR of fur seals increased with increasing water temperature, whereas sSMR of sea lions decreased with increasing water temperature. There were no species differences when comparing animals of the same sex. Our study suggests that fur seals have more flexibility in their physiology than sea lions, perhaps implying that they will be more resilient in a changing environment.

An expedition to the Sir Joseph Banks Group of islands, South Australia: vertebrate fauna

ABSTRACTThe vertebrate fauna of the Sir Joseph Banks Group includes 6 native (2 now extinct) and 7 introduced mammals, 76 native and 4 introduced birds and 15 native and 1 introduced reptile. The determination of the total mammal fauna includes examination of sub-fossil bone collections from both Reevesby and Spilsby Islands. Tammar wallaby, bush rat and greater stick-nest rats were only recorded from sub-fossils, but the successful reintroduction of the stick-nest rat to Reevesby Island begun in 1990, is described. Two species of bat are recorded from the two large islands, Spilsby and Reevesby. An Australian sea lion haul-out site on Blyth Island is described for the first time. Counts of the number of pairs of Cape Barren geese now breeding on Spilsby Island are also published here for the first time. The islands of the Sir Joseph Banks Group are very significant for the conservation of species with large and important breeding populations there such as Cape Barren geese, black-faced cormorants, white-faced storm petrels, little penguins and the black form of eastern tiger snakes while the successfully established greater stick-nest rat population on Reevesby Island is critical for the ongoing conservation of this threatened species.