King Island Research Articles

Per- and poly-fluoroalkyl substances (PFAS) do not accumulate with age or affect population survival in ruddy turnstone (Arenaria interpres)

Per- and poly-fluoroalkyl substances (PFAS) may threaten wildlife due to their high environmental persistence, toxicity potential and potential to bioaccumulate. Bioaccumulation may be particularly profound in long-lived animals inhabiting higher trophic niches. To date, there is a paucity of data on PFAS bioaccumulation potential in individual wild birds over their lifetime. In this study, we analysed within-individual PFAS contamination in a declining long-distance migratory shorebird, the ruddy turnstone (Arenaria interpres), and the variation in PFAS contamination with age by repeatedly sampling 19 individuals throughout their lives between 2007 and 2022. We found blood-sampled turnstones on their non-breeding grounds in King Island, Tasmania, exhibited no variation of PFAS contamination with age, with low overall circulating PFAS concentrations (<0.015–25 ng/g, median: 0.78 ng/g). Moreover, irrespective of the increased PFAS usage along the East Asian Australasian Flyway over the past two decades, ruddy turnstone survival remained consistent throughout the 15-year sampling period, with no temporal trend in percentage of juveniles in the population. From a conservation perspective, low concentrations of PFAS found in this study are good news as they suggest PFAS alone do not seem to threaten turnstone survival. However, the unknown effects of exposure to mixtures of pollutants may yet threaten turnstones.

Genomic insights into the critically endangered King Island scrubtit.

Small, fragmented or isolated populations are at risk of population decline due to fitness costs associated with inbreeding and genetic drift. The King Island scrubtit Acanthornis magna greeniana is a critically endangered subspecies of the nominate Tasmanian scrubtit A. m. magna, with an estimated population of < 100 individuals persisting in three patches of swamp forest. The Tasmanian scrubtit is widespread in wet forests on mainland Tasmania. We sequenced the scrubtit genome using PacBio HiFi and undertook a population genomic study of the King Island and Tasmanian scrubtits using a double-digest restriction site-associated DNA (ddRAD) dataset of 5,239 SNP loci. The genome was 1.48 Gb long, comprising 1,518 contigs with an N50 of 7.715Mb. King Island scrubtits formed one of four overall genetic clusters, but separated into three distinct subpopulations when analysed independently of the Tasmanian scrubtit. Pairwise FST values were greater among the King Island scrubtit subpopulations than among most Tasmanian scrubtit subpopulations. Genetic diversity was lower and inbreeding coefficients were higher in the King Island scrubtit than all except one of the Tasmanian scrubtit subpopulations. We observed crown baldness in 8/15 King Island scrubtits, but 0/55 Tasmanian scrubtits. Six loci were significantly associated with baldness, including one within the DOCK11 gene which is linked to early feather development. Contemporary gene flow between King Island scrubtit subpopulations is unlikely, with further field monitoring required to quantify the fitness consequences of its small population size, low genetic diversity and high inbreeding. Evidence-based conservation actions can then be implemented before the taxon goes extinct.

Genomic and transcriptomic resources for the brown thornbill (Acanthiza pusilla) to support the conservation of a critically endangered subspecies

Abstract* The brown thornbill (Acanthiza pusilla) is a songbird endemic to eastern Australia with five recognised subspecies within the brown thornbill. The most notable is the King Island brown thornbill (Acanthiza pusilla magnirostris) of which there are less than 100 remaining and based on expert elicitation are the most likely Australian bird to become extinct in the next 20 years. We sequenced PacBio HiFi reads of the brown thornbill to generate a high-quality reference genome 1.25Gb in size and contig N50 of 20.1Mb. Additionally, we sequenced mRNA from three tissues to generate a global transcriptome to aid with genome annotation. The generation of a reference genome for the brown thornbill provides an important resource to align additional genomic data which will be produced in the near future.

Dwarf emus from Baudin's voyage (1800–1804): an overlooked engraving by Nicolas Huet (1770–1830)

The French voyage of exploration to New Holland (Australia) between 1800 and 1804, commanded by Nicolas Baudin (1754–1803), made substantial natural history collections, notably capturing dwarf emus from the two distinct populations on King Island (Île King) in Bass Strait (December 1802) and Kangaroo Island (Île Decrès) (January 1803). Two of these emus survived their voyage to France, were housed briefly at the Empress Josephine's menagerie at Malmaison, and then the zoological park of the Jardin des Plantes in Paris. Both died in 1822. With the wild populations on both islands exterminated soon after Baudin's visit, two watercolours, one by Charles-Alexandre Lesueur (1778–1846) and one by Léon de Wailly ( fl. 1801–1824), have been central to the history of the dwarf emus. However, an important contemporary engraving by Nicolas Huet (1770–1830) depicting the two surviving emus in captivity has been overlooked. This essay explores the history of the images of the now extinct dwarf emus, as well as the production and significance of Huet's engraving.

Experimental measurements of wave-induced scour around a scaled gravity-based Oscillating Water Column Wave Energy Converter

Experimental measurements of wave scour are reported for a 1:20 scaled model of an operating 200 kW Oscillating Water Column (OWC) Wave Energy Converter (WEC) in King Island, Tasmania, Australia. Test cases include different wave conditions (Keulegan-Carpenter (KC) number range of 0.45-1.02) and multiple geometric changes to the device, which are compared to scour measurements taken in the field around the King Island OWC WEC device. The measurements therefore provide the first ever comparison of field data with a scaled laboratory model of scour around an OWC WEC.Results highlight that scour forms at the back corners of the device before undermining the structure with depths up to 64 mm (scour depth to structure width ratio, S/B, of 0.094), although the magnitude of this scour is shown to be reduced by 23% by curving the back corners. Scour at the front of the device is highly sensitive to the configuration of the front chamber door, with very different scour scenarios depending on whether the chamber door is open, closed, or removed entirely. Comparison with field data shows that undermining scour at the back of the device is reproduced in both settings, and this leads to settlement of the structure in both the laboratory and field. This suggests that the physical modelling forms an accurate representation of a real-world site, and therefore demonstrates scour processes with applicability to OWC WECs and other gravity-based bluff body structures such as caissons or gravity-based foundations.

Field Observations of Scour Behavior around an Oscillating Water Column Wave Energy Converter

This study provides the first ever published measurements of scour and morphological change around an Oscillating Water Column (OWC) Wave Energy Converter (WEC) device at a real-world site, with the intention of informing future designs to reduce costs of the technology. A 200-kW prototype OWC WEC was deployed at King Island, Tasmania, Australia in January 2021, providing a unique opportunity to monitor the device using a combination of dive footage, multi-beam surveys and bedrock surveys. Settlement of the device was observed and monitored before ceasing once the foundation made contact with the underlying bedrock at the site. It is hypothesized that the settlement is caused by scour undermining the gravity structure’s foundations. The processes causing this scour are explored and possible future design modifications are suggested to reduce the risk of scour and settlement.

Restoring community cohesion through positive education: applying a community resilience model

ABSTRACT The benefits of positive education initiatives are well understood in educational settings but less is known about how positive education can support remote communities to embrace change and become more resilient. This paper draws on the findings from an evaluative study of the Foundations to Flourish (F2F), a positive education programme, delivered on the remote setting of King Island, a sparsely populated Island in Bass Strait off Tasmania’s north west coast. In interpreting its findings, the study draws on community resilience models to understand the influence of the F2F programme on adaptive capacity, self-organisation and connectivity during a period of social and economic change. The paper concludes that positive education initiatives such as F2F play an important role in enhancing social connectedness and providing resources known to enhance resilience: positivity, learning experiences, respectful local leadership, effective service infrastructure and interactions that cut across normal close social circles creating a shared sense of purpose or direction.

Geotechnical Approach to Early-Stage Site Characterisation of Shallow Wave Energy Sites

Marine renewable energy is still in its infancy and poses serious challenges due to the harsh marine conditions encountered for wave or tidal installations and the survivability of devices. Geophysical and hydrodynamic initial site surveys need to be able to provide repeatable, reliable, and economical solutions. An oscillating water column wave energy converter is to be installed on the west coast of King Island, Tasmania. The location is in a high-energy nearshore environment to take advantage of sustained shoaling non-breaking waves of the Southern Ocean and required site-specific information for the deployment. We provide insight into scalable geophysical site surveys capable of capturing large amounts of data within a short time frame. This data was incorporated into a site suitability model, utilising seabed slope, sediment depth, and water depth to provide the terrain analysis needed to match deployment-specific characteristics. In addition, short-term hydrology and geotechnical work found a highly energetic seabed (near seafloor water velocities &lt;1 m/s) with sufficient bearing capacity (6 MPa). In a highly energetic environment, care was taken to collect the relevant data needed for an assessment of critical information to an emerging technology companies primary project. This is in addition to the malleable methodology for a site suitability model that can incorporate various weighted parameters to prioritise the location for shallow wave energy sites in general.

Eggs of extinct dwarf island emus retained large size.

Islands off southern Australia once harboured three subspecies of the mainland emu (Dromaius novaehollandiae), the smaller Tasmanian emu (D. n. diemenensis) and two dwarf emus, King Island emu (D. n. minor) and Kangaroo Island emu (D. n. baudinianus), which all became extinct rapidly after discovery by human settlers. Little was recorded about their life histories and only a few historical museum specimens exist, including a number of complete eggs from Tasmania and a unique egg from Kangaroo Island. Here, we present a detailed analysis of eggs of dwarf emus, including the first record of an almost complete specimen from King Island. Our results show that despite the reduction in size of all island emus, especially the King Island emu that averaged 44% smaller than mainland birds, the egg remained similar sized in linear measurements, but less in volume and mass, and seemingly had a slightly thinner eggshell. We provide possible reasons why these phenomena occurred.

Comparative wave measurements at a wave energy site with a recently developed low-cost wave buoy (Spotter), ADCP and pressure loggers

AbstractWave measurements from a new, low-cost, real-time wave buoy (Spotter) are investigated in a comparative study as part of a site characterization study at a wave energy candidate site at King Island, Tasmania, Australia. Measurements from the Sofar Ocean Spotter buoy are compared with concurrent measurements from a Teledyne RD Instrument (RDI) 1200 kHz Work Horse ADCP and two RBRsolo3 D wave16 pressure loggers. The comparison period between 8th August – 12th October 2019 provides both the shallowest and longest continuous published comparison undertaken with the Spotter buoy.Strong agreement was evident between the Spotter buoy and RDI ADCP of key wave parameters including the significant wave height, peak wave period, and mean wave direction, with the mean values of those parameters across the full deployment period agreeing within 3%. Surface wave spectra and directional spectra are also analyzed with good agreement observed over the majority of the frequency domain, although the Spotter buoy records approximately 17% less energy within a narrow frequency band near the peak frequency when compared to the RDI ADCP. Measurements derived from the pressure loggers routinely underestimated the significant wave height and overestimated the mean wave period over the deployment period. The comparison highlights the suitability of the Spotter buoy for low-cost wave resource studies, with accurate measurements of key parameters and spectra observed.

The Geochronology of Tasmanian Tin Deposits Using LA-ICP-MS U-Pb Cassiterite Dating

Abstract The island state of Tasmania is the most important tin producer in Australia. The spatial and genetic relationship between Tasmanian tin deposits and Devonian-Carboniferous granites, which intruded throughout the Tabberabberan orogeny, has long been understood. However, little geochronological data is available to link mineralization to nearby intrusions. In this study, we investigate the connection between 19 Tasmanian tin deposits and their potential source granites, using U-Pb cassiterite dating by laser ablation-inductively coupled plasma-mass spectrometry. Archean pegmatitic cassiterite was also characterized and used for the calibration of U-Pb ratios. Tin mineralization in Tasmania occurred between 391 ± 6.3 and 359 ± 7.8 Ma, which is coincident with most postorogenic granites of the Tabberabberan orogeny. In conjunction with the granite ages, cassiterite ages become younger from the east of the state to the west, and tin mineralization occurred over a protracted period spanning 32 m.y. Dating of several placer cassiterite samples produced unexpected results, such as the occurrence of 374 ± 4.7 Ma cassiterite on eastern King Island, an area known only to contain the 350 Ma Grassy granite, suggesting a distant provenance. Tasmanian cassiterite rarely shows evidence of Pb loss; however, some analyses are characterized by elevated Th and U, likely caused by microinclusions such as monazite, which may have a detrimental effect on cassiterite U-Pb dating. This study demonstrates the utility of cassiterite dating for understanding the origin of tin deposits in complex terrains with protracted periods of tin mineralization.

The Role of Low-Load Diesel in Improved Renewable Hosting Capacity within Isolated Power Systems

Isolated communities are progressively integrating renewable generation to reduce the societal, economic and ecological cost of diesel generation. Unfortunately, as renewable penetration and load variability increase, systems require greater diesel generation reserves, constraining renewable utilisation. Improved diesel generator flexibility can reduce the requirement for diesel reserves, allowing increased renewable hosting. Regrettably, it is uncommon for utilities to modify diesel generator control during the integration of renewable source generation. Identifying diesel generator flexibility and co-ordination as an essential component to optimising system hosting capacity, this paper investigates improved diesel generator flexibility and coordination via low-load diesel application. Case study comparisons for both high- and low-penetration hybrid diesel power systems are presented in King Island, Australia, and Moloka`i, Hawai`i, respectively. For King Island, the approach details a 50% reduction in storage requirement, while for Moloka`i the application supports a 27% increase in renewable hosting capacity.

Standard trade marks, geographical indications and provenance branding in Australia: What we can learn from King Island

AbstractThe topic of food geographical indications (GIs) in Australia is crucial to the free trade agreement negotiations currently proceeding between Australia and the EU, as the latter is seeking exclusive rights to use European GIs in Australia. Australia does not currently have a sui generis GI registration scheme for food products (other than wine) therefore we sought to contrast the standard trade mark system in operation with a hypothetical food GI scheme. We identified King Island (KI), Tasmania, as a suitable case study because the KI provenance brand is well known in the beef, dairy and lobster industries. We conducted desktop research, and interviews with producers in all industries on the Island. Our analysis suggests that food GIs could provide base‐line certainty about provenance while allowing competition around individual trade marks to proceed to the benefit of consumers and the Island community as a whole. Our study tends to reinforce the case favouring Australian legislative changes which would enable local producers to seek registration of food GIs around uncontroversial specifications.

Experimental investigation into 3D scour processes around a gravity based Oscillating Water Column Wave Energy Converter

Experimental investigations measuring both bed elevation changes and near-structure flow velocities were undertaken to investigate wave scour processes around a model Oscillating Water Column (OWC) Wave Energy Converter (WEC) for a range of incident wave conditions at approximately 1:20 scale. The experiment design was informed by a proposed 200 kW OWC WEC deployment site at King Island, Australia. The measurements provide the first experimental data on scour around an OWC WEC structure, and one of the most comprehensive experimental studies of wave scour around a large rectangular cross-section structure.High resolution scour erosion and deposition patterns were measured using an above-water laser-based system. For normally incident waves, scour holes were observed to develop on all four corners, and the size of the scour holes at the four corners increased with the Keulegan-Carpenter (KC) number. An additional scour hole/trench also formed along the upstream face of the OWC WEC due to the flow in/out of the OWC WEC internal chamber. Changing the incident wave propagation angle by 20° has a significant effect on the observed scour patterns, with reduced scour on the front and back corners but significant scour holes remaining on the other two corners. It is found that if the model is not sufficiently embedded into the sediment bed, scour can undermine a significant area under the structure, with quadrant shaped scour holes underneath the back corners extending to approximately 25% of the total base area, suggesting a risk of differential settlement in field conditions.

Biogeography and emerging significance of Actinobacteria in Australia and Northern Antarctica soils

Actinobacteria play key roles in terrestrial ecosystem functioning. They contribute to global carbon cycling through the decomposition of soil organic matter, increase plant productivity and are widely known as prolific producers of bioactive compounds essential for human and animal health. The almost century-old search for new members of the Actinobacteria has so far proceeded without systematic investigation of regions where novel, diverse and abundant actinobacterial populations occur. We show that such regions are found in Australia, a dry and warm continent with highly weathered soils. Here, Actinobacteria are highly abundant and evidently well-adapted to the warm, dry soil conditions. Australian continental actinobacterial diversity is associated with physicochemical factors, especially soil pHwater, exchangeable calcium and the regional climate. Patterns of their biogeography suggest that only a small fraction of Actinobacteria have the capability of dispersing throughout the Southern Hemisphere, especially across oceans. We identified a core soil actinobacterial community across mainland Australia of 2211 OTUs which declined to 490 OTUs when Tasmania, King Island, Christmas Island and Northern Antarctica were included. These 490 OTUs mapped to three families, i.e., Gaiellaceae, Micromonosporaceae and Nocardiaceae. Agricultural disturbance reduced actinobacterial diversity, hence undisturbed soils with native vegetation may be reservoirs that enrich the actinobacterial communities in adjacent agricultural soils. Interestingly, high OTU similarities between King Island and areas in Antarctica suggest a shared evolutionary history that persists to this day. In conclusion, the abundance of diverse Actinobacteria taxa in Australian soils suggests an increasingly important function of Actinobacteria as the world's soils become warmer and drier.

Seafloor Site Characterization for a Remote Island OWC Device Near King Island, Tasmania, Australia

We present findings from a geotechnical survey for a gravity-based Wave Energy Converter (WEC) to be installed in King Island, Tasmania. The goal of this work was to assess the deployment location for a 200 kW Oscillating Water Column (OWC) and to identify possible challenges for the foundation of the structure to make it Australia’s first operational offshore OWC for a remote offshore island. The proposed location for this OWC is the southeast coast of King Island, Tasmania, approximately in a depth of ~5.5 m LAT. The survey included sub-bottom profiling, sediment cores, surficial sediment strength by penetrometer drops, seabed imagery, as well as long-term deployment (&gt;6 months) of pressure sondes and an acoustic wave current profiler (AWAC). Our findings demonstrate that the WEC can be installed in the proposed location with significant wave height Hs ~1–1.5 m and peak period Tp of 12–14 s, and that the site exhibits sufficient sand coverage and quasisteady bearing capacity. The period between the survey and prospective deployment is only one year, demonstrating the efficiency of the survey methods (in particular, the use of the penetrometer) and OWC design but also the suitability of the candidate site for this device design.

The marine planktonic dinoflagellate Tripos: 60 years of species-level distributions in Australian waters

We reviewed 15572 Australian species-level records of the marine planktonic dinoflagellate Tripos Bory (formerly Ceratium Schrank, a genus now restricted to freshwater species). The genus is represented by over 50 species and numerous varieties and forms in Australian tropical, subtropical and temperate marine waters and the Southern Ocean. There exists considerable plasticity in the morphology of many species, which has confounded species delimitations and created uncertainty around their spatial distributions. We newly illustrate by light and electron microscopy the rarely reported Tripos hundhausenii (Schröd.) Hallegr. &amp;amp; Huisman comb. nov. first described from the Arabian Sea, but increasingly being observed in Sydney coastal waters. A large number of Tripos species are widely distributed in temperate, subtropical and tropical waters and their distributions have remained remarkably stable in Australian waters over the past 60–80 years. By contrast, we identified a narrow group of warm-water species, including T. belone (Cleve) F.Gómez, T. cephalotus (Lemmerm.) F.Gómez, T. dens (Ostenf. &amp;amp; E.J.Schmidt) F.Gómez, T. digitatus (F.Schütt) F.Gómez, T. gravidus (Gourret) F.Gómez, T. incisus (G.Karst.) F.Gómez, T. paradoxides (Cleve) F.Gómez and T. praelongus (Lemmerm.) F.Gómez, that are commonly encountered off Sydney, rarely found down to Eden and Batemans Bay or Bass Strait, but occasionally occur as far south as King Island and Maria Island, Tasmania. These rare tropical Tripos species are carried southward by the East Australian and Leeuwin Currents and deserve careful attention in monitoring for future range expansions, changes in seasonality or upwelling or incursion of deep tropical waters.

A Limerick Soundscape

A Limerick Soundscape Seán Lysaght (bio) I've written about growing up in a small Victorian terrace house in Limerick containing my father's book collection. With this stock of books throughout the house, even in the bedrooms, it was not easy to wrest some literary territory of my own out of our library-home, but this I gradually did with a modest store of French and Russian novels in translation, some slim volumes of poetry, and the books we read at school. As well as these "high-pilèd books," there was also a local literary scene in the city with a character—and characters—of its own. I use the term literary scene rather than literary tradition for those years; it could be argued, however, that Jim Kemmy's work in the 1980s and '90s, as editor of the Old Limerick Journal and of two important anthologies of Limerick writing, has now created what amounts to a literary tradition for the city and county. This is variously supported nowadays by the huge repository of printed holdings for North Munster at the Glucksman Library of the University of Limerick, the work of the Limerick Writers' Centre, and ongoing literary events and educational programs. All that was in the future when I started out, armed with my own hesitations and curiosity, to see what was on offer beyond the hall door. Our house at Osmington Terrace was just above Thomond Bridge, on the northern, Clare side of the River Shannon; the riverscape at this point is dominated by the imposing Norman walls and towers of King John's Castle and St. Mary's Cathedral. Stepping out of the house, often with a fishing rod or a pair of binoculars, I left the congested space of our home for the wide, generous sweep of Ireland's greatest river flowing through the city. It was a breezy, open topography of water with its cluster of history crowded to the waterfront; from here, standing atop St. Mary's Cathedral, the novelist Kate O'Brien celebrated the virtues of her native city as "a kind of cold restraint, an underflow of silence, a busy, throwaway glance." There were then two bridges over the Shannon: the old Thomond Bridge near the castle, and the newer Sarsfield Bridge a few hundred meters farther downstream. No one—except some hardened fishermen—ever lingered on either bridge because of exposure to the elements: you walked briskly across, buffeted in either case by the close passage of traffic. Thomond Bridge would [End Page 9] take me toward the castle, and the network of streets on King's Island, the old English town. Sarsfield Bridge brought me into the modern city center, where the streets had been laid out in a grid pattern by Georgian planners in the eighteenth century. During the summer, when swifts nesting in the castle walls screamed in the sky overhead, Limerick saw a good many North American tourists, who usually arrived through Shannon Airport. With these tourists in view, a group of literary-minded people held weekly readings in a room in the castle. Part of the intention here was to showcase some representative Irish culture for a visiting audience, but the evenings also became a platform for local poets to read. Popular classics such as Yeats's "Innisfree" took it in turns with literary novices like myself, and we all got a hearing from appreciative listeners. A great part of the appeal of these readings, I believe, was the venue: you had to climb an imposing set of steps between two towers of the castle, enter through a high, fortified, riveted doorway, climb an outer staircase, and negotiate a narrow passage to reach a spacious, round chamber. As there was little natural light here, even on those fine summer evenings, several candles were placed in bottles and hung around the walls. Seating was also rudimentary: readers and listeners alike perched on plain, backless benches. At about the same time, the Shannon Development Company was running medieval banquets in Bunratty and Knappogue Castles, to a high degree of comfort; there was a sense for us that the castle readings were a kind of low...

Rare earth element geochemistry of Australian Neoproterozoic carbonate: Constraints on the Neoproterozoic oxygenation events

Carbonate successions are principal geochemical archives of the extraordinary environmental changes that occurred during the Neoproterozoic Era. In this study, we present a stratigraphic record of carbonate rare earth element (REE) compositions from Neoproterozoic and Cambrian strata in central and southern Australia. The new REE results provide insight into the redox conditions of the Neoproterozoic-Cambrian ocean, the influence of glacial meltwater on carbonate precipitation, and Neoproterozoic-Cambrian paleoenvironmental changes. High Ce/Ce* and low Y/Ho suggest that the major Neoproterozoic and Cambrian carbonate accumulations of central and southern Australia formed in restricted marine environments that were largely dysoxic. Elevated ∑REE of mid-Cryogenian and early Ediacaran carbonate from the Amadeus Basin (central Australia) and King Island (Tasmania), respectively, are interpreted to reflect increased detrital mineral flux following periods of Cryogenian glaciation. REE data from the basal Ediacaran Cumberland Creek Dolostone of King Island suggest a transient episode of ocean oxidation in the wake of the terminal Cryogenian glaciation, but the balance of evidence suggests dominantly low oxygen ocean conditions during carbonate deposition in the remainder of the Neoproterozoic Era. An apparent mismatch in timing between carbonate deposition in central and southern Australia versus previously proposed mid-to-late-Ediacaran oxygenation events based on geochemical results from strata of South China highlights what may be important factors in reconciling varied geochemical records of Neoproterozoic-Paleozoic ocean oxygenation.

Comparison of inflow and outflow radial air turbines in vented and bidirectional OWC wave energy converters

This study analyses the aerodynamic performance of two unidirectional-radial-air-turbine configurations; inflow and outflow. These turbines were studied as the Power-Take-Off unit for application on a vented-OWC and a conventional-bidirectional-OWC with a twin-turbine topology, forming four different turbine-OWC configurations. These configurations were evaluated in terms of full-scale power extraction using extrapolated hydrodynamic experimental data of irregular waves for a King Island test site. The power extraction capacity was evaluated by defining a lower and upper bound of power generation under fixed and controlled-RPM schemes and the energy produced in each configuration was then compared against a state-of-the-art twin-rotor turbine. It was found that the difference between these power extraction bounds was lower in case of the outflow turbine, which shows this turbine is less sensitive to RPM variations than the inflow turbine. In addition, due to its lower resistance to the flow in direct mode, the outflow turbine has a smaller full-scale size than the inflow turbine. It was concluded that the outflow turbine provides better efficiency in a twin-turbine-OWC system, while the inflow turbine yields higher conversion efficiency in a vented-OWC system. The vented OWC equipped with a radial inflow turbine can obtain comparable power to the bidirectional OWC system.