Rottnest Island Research Articles

Serpentoviruses in Free-Ranging Shingleback Skinks (Tiliqua rugosa) in Western Australia and South Australia, Australia.

Serpentoviruses are strongly associated with upper respiratory tract disease in captive and free-ranging bluetongued skinks (Tiliqua spp.). In Australia, bluetongue serpentoviruses were first reported in shingleback skinks (Tiliqua rugosa) with upper respiratory tract disease that presented to wildlife rehabilitation facilities in Perth, Western Australia. Since then, serpentoviruses have been detected commonly in captive bluetongued skinks from most areas of Australia, yet knowledge about the prevalence and distribution of these viruses in free-ranging bluetongued skinks, and other skink species, remains limited. Oral swabs were collected from 162 shingleback skinks from four areas in Western Australia and neighboring South Australia to screen for bluetongue serpentoviruses by PCR. The proportions of PCR positives were 0% (0/4) for Rottnest Island (a small island west of Perth, Western Australia), 3% (1/32) for the Shire of Kent (∼5,600 km2 in the southwest of Western Australia), 1% (1/91) from an approximately 250,000 km2 area across South Australia and Western Australia, and 0% (0/35) from Mount Mary (∼150 km2 in the mid north of South Australia). Neither of the two PCR-positive shingleback skinks had overt signs of upper respiratory tract disease. These results are consistent with serpentoviruses occurring at a relatively low crude prevalence of 1.4% (95% confidence interval, 0.2-4.9%) across these areas, although the potential bias from sampling active and apparently healthy individuals may mean that this estimate is lower than the true prevalence. This contrasts with the high proportion of PCR positives reported in captive individuals. In the absence of experimental or observational data on viral clearance and recovery, Tiliqua spp. skinks that are intended for release into the wild should be housed with strict biosecurity to prevent interactions with captive individuals and screened to ensure that they are not PCR positive before release.

Coastal rockfall characterisation and risk management on Wadjemup - Rottnest Island, Western Australia

Coastal rockfall characterisation and risk management on Wadjemup - Rottnest Island, Western Australia

Complete genome sequence of a Salimicrobium sp. PL1-032A isolated from the pink hypersaline Pearse Lakes, Rottnest Island, Western Australia.

Salimicrobium sp. PL1-032A was isolated from Pearse Lakes, Western Australia. The sequenced genome consists of a single chromosome (2,705,688 bp) with a GC content of 47.2%. The isolation of Salimicrobium sp. PL1-032A contributes to the collection of culturable extremophiles and offers potential insight into the Pearse Lakes biome.

Complete genome sequence of Idiomarina sp. PL1-037 isolated from the pink hypersaline Pearse Lakes, Rottnest Island, Western Australia.

Idiomarina sp. PL1-037 was isolated from Pearse Lakes, Rottnest Island, Western Australia. The sequenced completed genome for PL1-037 is composed of a single chromosome (2,804,934 bp) with a GC content of 47.1%. Isolation of Idiomarina sp. PL1-037 provides insights about culturable extremophiles from the Pearse lakes microbiome.

Complete genome sequence of a Marinococcus sp. PL1-022 isolated from the pink hypersaline Pearse Lakes, Rottnest Island, Western Australia.

Marinococcus sp. PL1-022 was isolated from Pearse Lakes, Western Australia. The sequenced genome consists of a chromosome (3,140,198 bp; 48.2% GC) and two plasmids (58,083 bp and 19,399 bp; 41.4 and 50.7% GC-content, respectively). Isolation of Marinococcus sp. PL1-022 adds to the increasing repertoire of culturable extremophiles.

Two new species and new host and distribution records of Gnathia Leach, 1814 (Crustacea, Isopoda, Gnathiidae) from Western Australia and the Great Barrier Reef, Australia.

Gnathiaantennacrassasp. nov. from seagrass beds off Rottnest Island, Western Australia is the first record of any gnathiid from the entirety of Western Australia; the male can be distinguished from congeners by the stout peduncular articles of the antenna. Gnathiataurussp. nov. is described from two adult specimens reared from praniza larvae found infecting elasmobranch fishes at Heron Island, southern Great Barrier Reef; the males can be distinguished from all congeners by the dorsally strongly elongate mandibles and smoothly rounded mediofrontal process on the anterior part of cephalosome. Gnathiaaff.maculosa Ota & Hirose, 2009 is recorded from Australia, together with further records of G.trimaculata Coetzee, Smit, Grutter & Davies, 2009 and G.grandilaris Coetzee, Smit, Grutter & Davies, 2008, all from elasmobranch fishes.

Resolving the taxonomy of the Polysiphonia scopulorum complex and the Bryocladia lineage (Rhodomelaceae, Rhodophyta).

Cryptic diversity is common among marine macroalgae, with molecular tools leading to the discovery of many new species. To assign names to these morphologically similar species, the type and synonyms have to be examined, and if appropriate, new species must be described. The turf-forming red alga Polysiphonia scopulorum was originally described from Rottnest Island, Australia, and subsequently widely reported in tropical and temperate coasts based on morphological identifications. A recent study of molecular species delineation revealed a complex of 12 species in Australia, South Africa, and Europe. These species are placed in a taxonomically unresolved lineage of the tribe Polysiphonieae. The aim of this study was to resolve the genus- and species-level taxonomy of this complex and related species using molecular and morphological information. Three morphologically indistinguishable species of the complex were found at the type locality of P. scopulorum, preventing a straightforward assignment of the name to any of the molecular lineages. Therefore, we propose a molecularly characterized epitype. Polysiphonia caespitosa is reinstated for the only species found in its type locality in South Africa. We describe seven new species. Only one species of the complex can be morphologically recognized, with the other eight species indistinguishable based on morphometric analysis. The studied complex, together with another seven species currently placed in Polysiphonia and two Bryocladia species, formed a clade distinct from Polysiphonia sensu stricto. Based on observations of Bryocladia cervicornis (the generitype), we describe our seven new species in the genus Bryocladia and transfer another nine species from Polysiphonia to Bryocladia.

The cycle of seagrass life: From flowers to new meadows.

Understanding sexual reproduction and recruitment in seagrasses is crucial to their conservation and restoration. Flowering, seed production, seed recruitment, and seedling establishment data for the seagrass Posidonia australis was collected annually between 2013 and 2018 in meadows at six locations around Rottnest Island, Western Australia. Variable annual rates of flowering and seed production were observed among meadows between northern and southern sides of the island and among years. Meadows on the northern shore consistently flowered more intensely and produced more seeds across the years of the survey. Inter-site variation in clonal diversity and size of clones, seed production, wind and surface currents during pollen and seed release, and the large, but variable, impact of seed predation are likely the principal drivers of successful recruitment into established meadows and in colonizing unvegetated sands. The prolific but variable annual reproductive investment increases the probability of low levels of continuous recruitment from seed in this seagrass, despite high rates of abiotic and biotic disturbance at seedling, shoot, and patch scales. This strategy also imparts a level of ecological resilience to this long-lived and persistent species.

Rottnest Island Peafowl Pavo cristatus - a colourful history comes to an end

ABSTRACT During the early 1900s, the Acclimatization Committee of Western Australia introduced several species to Rottnest Island, most of which ultimately failed to establish. The Indian Peafowl Pavo cristatus was one that was successful and became synonymous with visits to the island. Peafowl eventually became too much of a nuisance and in 2009 the population was reduced by the Rottnest Island Authority leaving just male birds. In April 2022 the last peafowl died. We present the history of peafowl on Rottnest Island and describe how the introduced species' residence on Rottnest Island came to end.

Responses of intertidal invertebrates to rising sea surface temperatures in the southeastern Indian Ocean

IntroductionThe west coast of Western Australia (WA) is a global hotspot for increasing sea surface temperatures and marine heatwaves.MethodsWe used visual survey transects to compare mollusc and echinoderm populations on three coastal intertidal platform reefs on the Perth shoreline with two intertidal platforms at the west end of Rottnest Island (32°S) which are under the influence of the southward flowing Leeuwin Current.ResultsIn 1983, temperate species dominated Perth coastal molluscan diversity, but the tropical mussel Brachidontes sculptus dominated density. Species richness on coastal platforms remained constant in 2007 and 2021, but total densities were lower in 2007 as B. sculptus declined; partial recovery occurred on coastal platforms in 2021. Tropical species were a significant component of mollusc diversity and density at Rottnest Island in 1982 and 2007. Total mollusc density declined by 98% at the island sites of Radar Reef and 86% at Cape Vlamingh and total echinoderm density by 52% and 88% respectively from 2007 to 2021; species diversity also declined sharply.DiscussionTropical species have moved southward in WA subtidal environments, but tropical, temperate and WA endemic species all suffered losses of biodiversity and catastrophic declines in density of 90% or more on the two Rottnest Island intertidal platforms. Data presented here provide a sound basis for exploring the possible causes of the catastrophic mortality at the west end of Rottnest Island and monitoring for recovery.

An integrated approach to explore the monophyletic status of the cosmopolitan genus Hexabathynella (Crustacea, Bathynellacea, Parabathynellidae): two new species from Rottnest Island (Wadjemup), Western Australia

The Hexabathynella genus is the only genus of the family Parabathynellidae that has supposedly a worldwide distribution. Currently, there are 23 species described from five continents. In Australia, only two Hexabathynella species have been named from the eastern coast, however, a few taxa have been collected from Western Australia during stygofauna sampling as part of research studies and legislated compliance-based Environmental Impact Assessments. One of these areas includes Rottnest Island (Wadjemup), located offshore of Perth in Western Australia. Unpublished data on stygofaunal communities inhabiting the groundwater of the island refer to discrete abundances of copepods and syncarids, but no species description has been carried out. In this study, we describe two new species: Hexabathynella quokkai and H. bisetosa, expanding the characterization of the subterranean aquatic community at Rottnest Island, and using a COI, 18S and 12S sequence-based phylogeny to test the monophyletic status of the genus. Our findings shed new light on the distribution of Hexabathynella and its reported cosmopolitan distribution. http://zoobank.org/urn:lsid:zoobank.org:act:03634EAD-4D27-4446-AE53-4248303D5020 http://zoobank.org/urn:lsid:zoobank.org:act:1B325914-90FD-471E-AC03-20741C7C925A

Impact of COVID-19 on pest birds (Silver Gulls Larus novaehollandiae) on a popular tourist island

During the COVID-19 pandemic, Rottnest Island, Western Australia, a popular tourist destination, was closed to the public for 72 days (from 25 March 2020 to 5 June), so that it could be used as a quarantine facility. Silver Gulls Larus novaehollandiae were surveyed in the main settlement area over 429 days, beginning at the commencement of the quarantine period, with a focus on a previously identified problem area, the shopping mall. These surveys allowed for the comparison of Silver Gull numbers with and without the presence of easily accessible anthropogenic food. The number of Gulls was extremely low during the quarantine period, followed by a 578% increase in the same period the following year when visitors returned. During the period of food scarcity, many of the Gulls appeared to have left the Island, which suggests that the number of pest birds on Rottnest Island can be influenced by the amount of anthropogenic food available to them.

Recreational fishing pressure impacts the density and behaviour of the western rock lobster (Panulirus cygnus, George): evidence from small, no-take marine reserves

Abstract It is unknown whether lobster behaviour is sensitive to fishing, as has been previously suggested for fish. This study investigated the impacts of recreational fishing on the wariness of western rock lobster (Panulirus cygnus, George) through comparisons between fished sites and no-take reserves (NTRs) at Rottnest Island. We used visual census to survey the density and size structure of lobster at sites inside and outside three comparable NTRs, and baited remote underwater video to study the behaviour of lobster at comparable sites. The density of legal-sized P. cygnus was twice as high within NTRs (0.34 ± 0.05) than fished sites (0.16 ± 0.03). P. cygnus also spent less time with bait in fished sites (0.42 ± 0.15 min) than NTRs (1.15 ± 0.28 min). This study provides the first evidence that behaviour of decapods, namely P. cygnus, is sensitive to noninjury-related disturbance associated with recreational fishing, with higher wariness in fished areas. Investigation is required into potentially confounding biotic and abiotic factors to further explore the applicability of lobster wariness as an indicator for fishing pressure.

Postcolonial churn and the impact of the criminal justice system on Aboriginal people in Western Australia, 1829–2020

This article analyses how the criminalisation and imprisonment of Aboriginal people operated as tools of colonisation in Western Australia (WA) in the nineteenth century, and how this shaped the postcolonial criminal justice system. The racialised double standard embedded in the colonial foundations of state institutions, including the criminal justice system, rippled across generations of Aboriginal people: a reiterative and disruptive process that we dub the ‘postcolonial churn’. This term, adapted from the ‘carceral churn’, describes the destabilising mobilisations embedded in carceral and settler-colonial logics over the long term. It uses data from archival prison registers (Rottnest Island 1838–1931 and Roebourne Prison 1908–1961), as well as historic court, police and newspaper data to map the use of the criminal code in protecting and expanding colonial property rights in the original waves of settler-colonisation. WA is an outlier among the Australian colonies: it was the largest in terms of size (2,642,753 km2), the last colony to receive European convicts (1850–1868), and the last to be awarded self-government (1890). This created a situation where the British government dictated policy for legal forms of subjugation of Aboriginal people at the frontier (first for resisting pastoral industry, later as workers in it) which butted up against localised extra-legal violence by police and settlers. We can trace this dichotomy between policy and practice in the development of surveillance and policing of Aboriginal populations across time and settler-colonial space due to the protracted pace of frontier ‘development’. Revealing the mediated historical aspects of structural racism is crucial to analysing the persistence of racialised policing in postcolonial settings and understanding why, despite repeated inquiries into mistreatment of Aboriginal people, institutional inertia remains.

Coral Communities on Marginal High-Latitude Reefs in West Australian Marine Parks

Many temperate reefs are experiencing a shift towards a greater abundance of tropical species in response to marine heatwaves and long-term ocean warming worldwide. Baseline data for coral communities growing in high-latitude reefs is required to better understand ecosystem changes over time. In this study, we explore spatial and temporal trends in the distribution of coral communities from 1999 to 2019 at 118 reef sites within the five marine parks located in the south-west of Western Australia (WA) between 30° to 35° S. Our estimates of coral cover were generally low (<5%), except for a few sites in Jurien Bay Marine Park and Rottnest Island Marine Reserve where coral cover was 10% to 30%. Interannual changes in genera assemblages were detected but were not consistent over time, whereas significant temporal increases in coral cover estimates were found at the lowest latitude site in Jurien Bay. Coral assemblages were primarily distinguished by Turbinaria spp. at Marmion Marine Park and Ngari Capes Marine Park, and Pocillopora spp. and Dipsastraea spp. at Rottnest Island and Jurien Bay. Our findings suggest that conditions in south-west WA are favorable to the ongoing survival of existing genera and there were minimal signs of expansion in coral cover at most study sites. Coral cover and composition on these reefs may, however, change with ongoing ocean warming and increased occurrence of marine heatwaves. This study provides a valuable benchmark for assessing future changes in coral assemblages and highlights the need for targeted hard-coral surveys to quantify subtle changes in high-latitude coral community assemblages.

Feeding ecology of a threatened coastal seabird across an inner shelf seascape

Feeding studies provide important information about animals and the environments in which they live. Yet little is known about the diet of the Australian Fairy Tern Sternula nereis nereis, despite the species being listed as threatened (Vulnerable) and in need of research. This study investigated the dietary composition of this bill-loading seabird, at three colony sites of an inner shelf seascape (two marine and one estuarine) using non-invasive digital photography and direct observations (number of observations [n] = 9854). Small surface schooling, inshore spawning fishes were the most important prey at all sites. Blue Sprat Spratelloides robustus, hardyheads (Atherinidae spp.), and garfishes Hyporhamphus spp. dominated the diet, contributing ≥75% of all prey at each site. The abundance of these fishes, whose spawning period overlapped the Fairy Tern breeding season in south-western Australia (October to February), is likely an important factor influencing the location of Fairy Tern colonies. Multivariate statistical analyses showed that dietary composition differed significantly among colony sites, breeding seasons, between courtship and chick feeding, and time of day. Blue Sprat, Beaked Salmon Gonorynchus greyi, and flyingfishes (Exocoetidae spp.) were present in greater proportions at Rottnest Island and Penguin Island (marine sites) than at Point Walter (estuarine). In contrast, hardyheads, Tailor Pomatomus saltatrix, and Yelloweye Mullet Aldrichetta forsteri were more common at Point Walter. Garfishes were around twice as important at Penguin Island than the other sites. Differences in habitat and fish species assemblages at each site may explain the observed spatial trends in dietary composition, while environmental factors, e.g. sea surface temperature and freshwater discharge, and natural interannual variability may explain the observed temporal trends in diet. Fish donated for courtship were ∼21% (12 mm) longer than those provisioned to chicks and the composition of prey in the diet of Fairy Terns differed between courtship and chick feeding at both Point Walter and Penguin Island. Differences in prey handling capabilities and nutritional requirements of adult females and chicks may explain these differences. Dietary composition differed significantly among diurnal periods at Point Walter and Penguin Island, with the greatest differences observed between morning and afternoon periods. At least 30 prey species were recorded, suggesting a degree of feeding opportunism. However, the large proportion of Blue Sprat, particularly at marine colony sites, highlights a potential vulnerability of Fairy Terns to changes in prey availability during their breeding period.

A recurring population of the sea hare Bursatella hirsuta (Gastropoda: Aplysiidae) at Rottnest Island, Western Australia

ABSTRACT In many, but not all, years a recurring population of the marine aplysiid Bursatella hirsuta occurs on an intertidal limestone platform stretching between Little Armstrong Bay and North Point at Rottnest Island, Western Australia. Using a transect/quadrat method, we measured densities of B. hirsuta during the austral summer of 2020/2021. No individuals were present in December 2020, but a population with a mean density of 16.5 ± 1.6 (SE) inds m−2 was present on 17 January 2021. Density was low in bare sand (2.6 ± 3.2 inds m−2) and in the seagrass Amphibolis antarctica (2.0 ± 1.4 inds m−2), high in mixed algae, mostly Phaeophyceae (18.2 ± 1.8 inds m−2) and greatest (27.2 ± 14.3 inds m−2) in a small number of quadrats with a mixture of sand and algae or sand and A. antarctica. The population was estimated at >600,000 individuals. The species was present in February but had disappeared by late March 2021. The population at Little Armstrong Bay and North Point provides a fertile opportunity for developing a better understanding of the biology of B. hirsuta and broader questions of boom-and-bust populations.

Clinical Pharmacist role in a Medical Assistance Team during novel coronavirus (COVID-19) quarantine.

To the Editor, Quarantine to control infectious disease outbreaks such as COVID-19 has long been utilised by Australia, and involves restricting the movement of individuals or groups presumed to have been exposed to the home or a designated facility.1, 2 We describe a clinical pharmacist role servicing quarantined passengers on two separate occasions – involving an international cruise ship, and an international flight, respectively – where approximately 200 returned travellers on each occasion completed 14 days mandatory quarantine on Rottnest Island, 20 km offshore from Fremantle port. Rottnest Island has roughly 330 permanent residents, however it can accommodate 15 000 people in peak tourist periods.3 The island has basic medical services: a Nursing Post with two nurses, and a General Store with a Schedule 2 Poisons Permit and a limited range of medications. The Western Australian Medical Assistance Team (WAMAT) is a multidisciplinary health support team sent to disaster sites at short notice.4 WAMAT was deployed to Rottnest Island to provide medical management of passengers for the two quarantine periods. Tourists were evacuated and quarantine zones were established. WAMAT usually comprises medical doctors, registered nurses, paramedics and logisticians, and pharmacists are not routinely included. For the first quarantine period involving elderly cruise ship passengers, a pharmacist was requested to assist with the anticipated high medication burden. After this successful deployment, WAMAT also requested the pharmacist for the subsequent quarantine. Quarantined passengers completed health questionnaires on arrival. Medication resupplies used the Commonwealth ‘special authority for emergency supply of Schedule 4 medicines during COVID-19’ and were authorised by the pharmacist. New prescriptions were handwritten by the WAMAT doctor, screened by the pharmacist and emailed to Fiona Stanley Hospital (FSH), a quaternary hospital with governance for the Nursing Post, for dispensing. Medications were supplied in sealed boxes via the passenger ferry. WAMAT staff provided daily medical rounds, including assessment of passengers in their quarantine accommodation for COVID-19 symptoms. Several important pharmacist roles have been identified during the prevention, preparedness and response phases of disasters;5 however, to our knowledge there is no description in the literature of the pharmacist contribution to patient management during quarantine periods for a pandemic. The request for pharmacist inclusion in the WAMAT team during the second quarantine deployment is recognition of the unique skills they provide, particularly where access to standard medical care is limited. The authors have no conflicts of interests to declare.

Heavy metal incorporation in foraminiferal calcite under variable environmental and acute level seawater pollution: multi-element culture experiments for Amphisorus hemprichii.

The accelerated release of heavy metals into the coastal environments due to increasing anthropogenic activities poses a severe threat to local marine ecosystems and food chains. Although some heavy metals are essential nutrients for plants and animals, higher concentrations can be toxic and hazardous. To mitigate this threat, developing quantifiable proxies for monitoring heavy metal concentrations in near-shore marine environments is essential. Here, we describe culture experiments to quantify uptake of some heavy metals using live juvenile specimens of the large benthic foraminifera (LBF) Amphisorus hemprichii collected from the subtropical waters of Rottnest Island located ~20 km offshore Perth, South West Australia. The uptake of Mn, Ni, Cd, and Pb in the newly precipitated chambers of Amphisorus hemprichii in the laboratory was characterized using the micro-analytical technique, laser ablation inductively coupled plasma mass spectrometry. We found no significant increase in Mn, Ni, Cd, and Pb incorporation in the tests of Amphisorus hemprichii with increasing temperature and light intensities. Importantly, we found that changes in the concentrations of Mn, Ni, and Cd in the A. hemprichii tests are directly proportional to those in the culture solution over a wide range of concentrations. The calculated partition coefficients for Mn, Ni, and Cd from our culture experiments are 1.3±0.2, 0.3±0.04, 2.6±0.3, respectively. These multi-element calibration studies now enable A. hemprichii to be utilized as a naturally occurring bio-archive to quantitatively monitor the anthropogenic pollution of Mn, Ni, and Cd in coastal waters.

Metabarcoding under Brine: Microbial Ecology of Five Hypersaline Lakes at Rottnest Island (WA, Australia)

Hypersaline ecosystems—aquatic environments where concentration of salt exceeds 35 g L−1—host microbial communities that are highly specialised to cope with these extreme conditions. However, our knowledge on the taxonomic diversity and functional metabolisms characterising microbial communities in the water columns of hypersaline ecosystems is still limited, and this may compromise the future preservation of these unique environments. DNA metabarcoding provides a reliable and affordable tool to investigate environmental dynamics of aquatic ecosystems, and its use in brine can be highly informative. Here, we make use of bacterial 16S metabarcoding techniques combined with hydrochemical analyses to investigate the microbial patterns (diversity and functions) from five hypersaline lakes located at Rottnest Island (WA). Our results indicate lake-driven microbial aquatic assemblages that are characterised by taxonomically and functionally moderately to extremely halophilic groups, with TDS (total dissolved solids) and alkalinity amongst the most influential parameters driving the community patterns. Overall, our findings suggest that DNA metabarcoding allows rapid but reliable ecological assessment of the hypersaline aquatic microbial communities at Rottnest Island. Further studies involving different hypersaline lakes across multiple seasons will help elucidate the full extent of the potential of this tool in brine.