Jervis Bay Research Articles

Intensive temporal and spatial sampling of polychaete biodiversity reveals significant implications for impact assessment and marine park design

Abstract Intensive temporal and spatial sampling of benthic infauna have rarely been analysed to improve impact assessment or conservation planning. An impact assessment started in the late 1980s in Jervis Bay (Australia) provided a spatially, temporally and taxonomically comprehensive benthic invertebrate dataset. While the proposed development did not eventuate, the area was later declared a multi‐zone marine park. We specifically used the polychaete data which included nine sampling times (February 1989 to June 1991) in seagrass and unvegetated sediments across multiple sites to identify ecological patterns that could inform current and future conservation management and impact assessment. The polychaete assemblage was diverse with 171 species, many of them rare (40% < 10 individuals). Variation was greatest at small spatial scales (metres) for abundances and diversity, and there was substantial spatio‐temporal variation due to inconsistent site differences. Most species occurred in both unvegetated and seagrass sediments, though several were more abundant or restricted to one habitat (39% and 3% only found in unvegetated or seagrass, respectively), or showed bathymetric differences in abundances (e.g., Eunice cultrifera and Lumbrineris cf. latrelli). The current marine park zoning representatively covered polychaete biodiversity, as all sites were generally similar in terms of abundances and species richness. It also representatively covered seagrass and unvegetated sediments and the bathymetric range of the embayment. These findings reinforce the utility of using habitats as surrogates to representatively zone for biological diversity. The high levels of spatial and spatio‐temporal variation in abundances and diversity only allowed detection of environmental impacts with >70% effect sizes even if numerous sites and times were sampled (i.e., > seven sites and > eight times). This suggests that most univariate measures for polychaetes would only be useful to detect enormous effects, and effective impact assessment might require more sophisticated multivariate approaches.

Consequences of Juvenile Fish Movement and Seascape Connectivity: Does the Concept of Nursery Habitat Need a Rethink?

Estuarine and adjacent inshore habitats have long been recognised as important nursery areas for fishes before they disperse to coastal habitats. Assessing nursery function supports spatial and fisheries management, yet work commonly focusses on singular habitat types. Re-considering how juvenile fish connect habitats may improve our understanding of nursery function and the scales that recruits are supplied to coastal fisheries. This study quantified the juvenile movements of two harvested fishes in south-eastern Australia, luderick (Girella tricuspidata) and yellowfin bream (Acanthopagrus australis). Acoustic tags were used to track 33 luderick and 20 yellowfin bream from seagrass meadows for up to ~400 days in Jervis Bay Marine Park. Both species had relatively small home ranges (< 7 km2) and exhibited site attachment to seagrass meadows where they were released. Most luderick and yellowfin bream were detected moving 100’s metres to kilometres to reefs adjacent to seagrass, although these movements were not habitat shifts. Rather, reef-ward movements represented repeated visits that lasted days to months before fish returned to seagrass, suggesting that these movements may be explorations in search of suitable adult habitat. Strong retention within an existing marine reserve was observed, with only five of 33 fish tagged within reserves crossing the boundary into fished waters. Overall, our results demonstrate that juvenile fish use and connect multiple habitat types during their movements. These findings support the broadening of the nursery concept from single habitats to a mosaic of functionally connected habitat patches (dubbed ‘seascape nurseries’).

Robust Doppler compensation for low frequency underwater communications

Impairment caused by Doppler frequency shift and harsh channel condition distinguish underwater acoustic communications from radio communications. Slow speed of acoustic waves produces relatively high Doppler shift and result in expansion or compression in time samples, which is known as Doppler scaling. In particular, the Doppler scaling causes significant carrier frequency offset (CFO) in orthogonal frequency division modulation (OFDM). To compensate the CFO, it is essential to resample signal samples according to the Doppler scale. In theory, the Doppler scale can be estimated by measuring the distance between peaks of the matched filter output of consecutive Doppler-invariant preambles. In practice, multi-path reflections and non-orthogonality between the HFM and OFDM payload produce large numbers of local false peaks. In this paper, we propose a robust Doppler estimation technique by employing constant false alarm rate (CFAR) filter to remove false peaks. We validate the performance of the proposed scheme through two sea-trials carried out in shallow water near Jervis Bay, Australia. In the sea-trials, a slow-moving towed hydrophone array was deployed as the receiver and the source was a stationary, low source level, vertical transmit array. Sea-trial results demonstrated up to 112bps information rate using bit-interleaved coded OFDM over 400 Hz bandwidth.

Characterising resting patterns of mother-calf humpback whale groups in a semi-enclosed embayment along the Australian east coast migration pathway

On migration from low latitude breeding grounds to high latitude feeding grounds, humpback whale mothers and calves spend time resting in coastal embayments. Unlike other areas where resting has been documented, Jervis Bay, on Australia’s east coast, is remote from both breeding and feeding grounds, and provides a unique opportunity to compare resting behaviour observed within a semi-enclosed embayment to observations offshore. Land-based, and UAV surveys were conducted in Jervis Bay in 2018, 2019, and 2021. We show that (i) a disproportionately high percentage of groups with a calf enter Jervis Bay during the southbound migration, (ii) travelling speeds are significantly slower in the Bay compared to offshore, indicating resting behaviour, and (iii) aerial observations highlight resting and nurturing behaviour. Subsequently, we conclude that Jervis Bay is an important area for resting mother-calf humpback whale groups. Comparison with reports of resting behaviour during migration in areas nearer the breeding grounds shows commonalities that characterise resting behaviour in mothers and calves. This characterisation will allow improved monitoring and management of humpback whales in nearshore embayments during a critical stage of calf development, particularly those with increased anthropogenic activities.

Population connectivity across east Australia's bioregions and larval duration of the range‐extending sea starMeridiastra calcar

AbstractThe diversity and distribution of marine species in eastern Australia is influenced by one of the world's strongest western boundary currents, the East Australia Current, which propels water and propagules poleward, a flow intensifying due to climate change.Population genetic structure of the asterinid sea starMeridiastra calcarwas investigated across its range in eastern Australia (12° of latitude, 2,500 km) from northern New South Wales to its poleward‐extending range in Tasmania at the southern edge influence of the East Australia Current.Population structure and connectivity ofM. calcarwere examined across six bioregions using six microsatellite loci (nuclear DNA) and the control region (mitochondrial DNA). The potential influence of the extent ofM. calcar's intertidal rock platform habitat was also assessed.Genetic structure analysis indicated that the Hawkesbury Shelf contained distinct genetic clusters, whereas the two sites in the Batemans Shelf differed from each other, with Jervis Bay Marine Park having just one genetic cluster. The Manning Shelf, Twofold Shelf, and Bruny bioregions all had similar genetic composition.Strong self‐seeding (68–98%) was indicated by microsatellite loci for all bioregions, with lower (0.3–6.5%) migration between bioregions. Poleward (New South Wales to Tasmania) migration was low except from the Manning Shelf (30%).Contemporary population connectivity and genetic structure ofM. calcarappear to be influenced by ocean currents, habitat distribution, and its short planktonic larval duration, which was a minimum of 12–14 days, depending on availability of a settlement cue.The dominance of unique genetic groups in the Hawkesbury bioregion shows the importance of this region forM. calcarand possibly a diversity of co‐distributed rock platform species. This highlights how important it is to have a large marine park in the Hawkesbury bioregion, which is presently lacking.

Intraspecific variation in muscle growth of two distinct populations of Port Jackson sharks under projected end-of-century temperatures

Although pervasive, the effects of climate change vary regionally, possibly resulting in differential behavioral, physiological, and/or phenotypic responses among populations within broadly distributed species. Juvenile Port Jackson sharks (Heterodontus portusjacksoni) from eastern and southern Australia were reared at their current (17.6 °C Adelaide, South Australia [SA]; 20.6 °C Jervis Bay, New South Wales [NSW]) or projected end-of-century (EOC) temperatures (20.6 °C Adelaide, SA; 23.6 °C Jervis Bay, NSW) and assessed for morphological features of skeletal muscle tissue. Nearly all skeletal muscle properties including cellularity, fiber size, myonuclear domain, and satellite cell density did not differ between locations and thermal regimes. However, capillary density was significantly influenced by thermal treatment, where Adelaide sharks raised at current temperatures had a lower capillarity than Jervis Bay sharks raised at ambient or projected EOC temperatures. This may indicate higher metabolic costs at elevated temperatures. However, our results suggest that regardless of the population, juvenile Port Jackson sharks may have limited acclimatory potential to alter muscle metabolic features under a temperature increase, which may make this species vulnerable to climate change.

Amazing diversity of Nothria (Annelida, Onuphidae) in the Australian deep sea

The epibenthic onuphid genus Nothria Malmgren, 1867 presently comprises 21 accepted species. We are reporting here on specimens collected during six deep-sea expeditions of the RV Investigator from 2015–2018 to the Great Australian Bight (GAB) and off eastern Australia from Tasmania to Queensland, describing eight new species of Nothria. This is the first integrated study of the genus, sequencing the markers COI, 16S rDNA and 28S rDNA from 37 specimens and employing conventional and exploratory morphological characters as well as tube consistency and structure for identification. Molecular data provided strong support for recognition of the eight new species and the Nothria otsuchiensis Imajima, 1986 species complex. Since the analysis of morphology between the specimens of this complex has not revealed any obvious differences, it may represent a complex of cryptic species. Nothria digitata sp. nov. was collected at a depth of 400 m whilst the remaining seven new species are from depths of 980–2751 m. Nothria deltasigma sp. nov., N. digitata sp. nov. and N. minima sp. nov. were collected at a single station each, while N. josae sp. nov. and N. simplex sp. nov. were found at two stations. However, N. delta sp. nov. displayed the widest distribution, occurring at GAB, Tasmania and Jervis Bay Marine Park, NSW. Most stations yielded only one species, Jervis Bay Marine Park and south of Brians, Tasmania, harboured two, but an astounding example of sympatry was discovered at Huon Marine Park, Tasmania, where three species, N. delta sp. nov., N. lizae sp. nov. and N. orensanzi sp. nov. were collected together in one station.

Using stable-isotope analysis and acoustic telemetry data to infer broad-scale migration patterns of Port Jackson sharks (

Context Understanding migratory species’ habitat selection is complicated by variation in movement strategies. Stable-isotope analysis provides a powerful tool to investigate such variation. Aims We used acoustic telemetry and stable-isotope analysis to better understand the movement strategies of Port Jackson sharks. Methods We compared the δ13C and δ15N values of fin tissue from acoustically tracked individuals that undertook three distinct movement strategies. Hierarchical cluster analysis was then used to cluster movement strategies of a larger sample of sharks on the basis of δ13C and δ15N values. Key results Tracked individuals that remained in Jervis Bay were enriched in 13C, compared with those that migrated south after the breeding season. Individuals were assigned to six clusters and δ13C and δ15N values indicated that migrating males and females may utilise different geographical areas or niches during the non-breeding season. Conclusions By using stable isotope analysis and acoustic telemetry, we identified distinct groups of Port Jackson sharks with similar broad-scale movement strategies. Implications These variable movement strategies may lead to different reproductive fitness advantages on an individual and population level, having implications for the broader ecosystem, given the important role mesopredators play in southern reef marine ecosystems.

Redescription of Euastacus clydensis Riek, 1969 (Crustacea: Parastacidae), a valid species of spiny crayfish from southern New South Wales, Australia

The Giant Sydney Crayfish (Euastacus spinifer (Heller, 1865)) was thought to have a wide range in New South Wales, Australia, spanning some 600 km north-south. A recent extensive molecular phylogenetic and population genomic analysis of E. spinifer across its geographical range revealed strong population structure corresponding to several major geographically correlated clades, the southernmost clade being the most genetically divergent and clearly a separate species. This southern clade corresponds to the junior synonym E. clydensis Riek, 1969 and is sister to the clade comprising the remaining populations of E. spinifer and Euastacus vesper. We formally remove E. clydensis from the synonymy of E. spinifer, increasing the recognised number of species of Euastacus to 54. Euastacus clydensis is redescribed based on type and other material, and is distinguished from E. spinifer by differences in abdominal spination and the form of the antennal scaphocerite. Euastacus clydensis has a restricted southern New South Wales range in the Shoalhaven and Jervis Bay-Clyde River catchments, from Moss Vale south to the vicinity of Clyde Mountain; much of the known range of E. clydensis was burnt in the 2019-2020 eastern Australian megafires.

Enhancing UAV images to improve the observation of submerged whales using a water column correction method

Enhancing <scp>UAV</scp> images to improve the observation of submerged whales using a water column correction method

In the line of fire: Debris throwing by wild octopuses.

Wild Octopus tetricus frequently propel shells, silt, and algae through the water by releasing these materials from their arms while creating a forceful jet from the siphon held under the arm web. These "throws" occur in several contexts at a site in Jervis Bay, Australia, including in interactions with other octopuses. Material thrown in interactive contexts frequently hits other octopuses. Some throws appear to be targeted on other individuals, as suggested by several kinds of evidence: Throws in interactive contexts were more vigorous than others, and more often used silt, rather than shells or algae. High vigor throws were more often accompanied by uniform or dark body patterns than other throws. Some throws were directed differently from beneath the arms and such throws were more likely to hit other octopuses. Throwing at other individuals in the same population, as apparently seen in these octopuses, is a rare form of nonhuman projectile use, previously seen only in some social mammals.

Characterising the Aboveground Carbon Content of Saltmarsh in Jervis Bay, NSW, Using ArborCam and PlanetScope

Coastal ecosystems, including saltmarsh, provide important ecosystem services, including blue carbon storage, nutrient cycling, and coastal protection. The loss or degradation of saltmarsh ecosystems may undermine their capacity to provide these services and drive carbon emission increases. The accurate mapping and monitoring of the aboveground carbon content in these ecosystems supports protection and rehabilitation activities. Previous studies have used medium resolution satellites (e.g., Landsat and Sentinel-2) to characterise saltmarsh communities; however, these platforms are not well suited to the fine-scale patchiness of the saltmarsh ecosystems found in Australia. Here we explore the potential of a very high spatial resolution (0.15 m), seven-band multispectral ArborCam airborne sensor and 3 m images captured by the PlanetScope satellite constellation for mapping and monitoring the aboveground carbon content of a saltmarsh ecosystem in Jervis Bay National Park, Australia. The Normalized Difference Vegetation Index (NDVI) derived from an ArborCam image was calibrated to aboveground carbon content using field survey data. Strong linear relationships between the ArborCam NDVI and aboveground carbon content were found when survey data were partitioned by species. The mean aboveground carbon content derived from the calibrated ArborCam image was 1.32 Mg C ha−1 across the study area; however, this is likely to have been underestimated. A monthly NDVI time series derived from 12 PlanetScope images was analysed to investigate the short-term temporal variation in saltmarsh phenology, and significant intra-annual variation was found. An exploration of potential drivers for the variation found that local rainfall was a potential driver. The combination of the very high spatial resolution airborne ArborCam image and the regular 3 m capture by PlanetScope satellites was found to have potential for accurate mapping and monitoring of aboveground carbon in saltmarsh communities. Future work will focus on improving aboveground carbon estimates by including a very high spatial resolution species distribution map and investigating the influence of temporal variations in saltmarsh spectral response on these estimates.

Genetic differentiation in the threatened soft coral Dendronephthya australis in temperate eastern Australia

AbstractThe endangered soft coral Dendronephthya australis faces substantial population decreases in central eastern Australian waters. Despite uncertainty about the cause of these declines, the population genetics of the species has not been investigated. Genetic analysis suggests that D. australis is a single species within the family Nephtheidae, confirming identifications based on morphological characteristics only. Soft coral colonies were distributed from Seahorse Gardens in Port Stephens to Jervis Bay in temperate Australian waters, a distance of some 400 km. Genetic differentiation was observed along this distribution using SNP genotyping. Relatively high levels of genetic differentiation were observed between Jervis Bay and the other sites, indicating limited gene flow between this location and others. Moreover, the genetic distinctiveness, low diversity and heterozygote excess at this southern location suggested that it was subjected to a recent population decline and genetic bottleneck. Colonies at Seahorse Gardens and Ettalong, approximately 150 km south of Seahorse Gardens, displayed greater genetic diversity, making these sites more likely to host ancestral populations and to have acted as refugia. Recent substantial decreases in population sizes at these locations are particularly concerning, and these locations require immediate conservation attention.

Perspectives on biotic responses to repeated wildfires from decades of long-term empirical studies

ABSTRACT Fire can have marked impacts on biodiversity and on ecosystem condition. However, it is the sequence of multiple fires over a prolonged period of time which can have the most marked effects on biodiversity and on ecosystem condition. A good understanding of these effects comes from long-term studies. In this article we outline some of the key perspectives on the effects of fire on ecosystems and biodiversity from two large-scale, long-term monitoring studies in south-eastern Australia. These are studies in the montane ash forests of the Central Highlands of Victoria and at Booderee National Park in the Jervis Bay Territory. These studies have shown that the effects of fires are strongly influenced by: (1) The condition of an ecosystem before a fire (e.g. the age of a forest at the time it is burnt). (2) Conditions after the fire such as the extent of herbivory in regenerating vegetation and whether the ecosystem is subject to post-fire (salvage) logging. (3) Fire history (e.g. the number of past fires and the time since the previous fire). And, (4) Interactions between fire and other ecosystem drivers such as logging. We discuss some of the key implications for conservation and resource management that arise from these studies including the need to: (a) Reduce the number of stressors in some ecosystems to facilitate post-fire recovery. (b) Recognize that pre-fire human disturbances can elevate fire severity in some forest ecosystems, with corresponding negative effects on elements of the biota, and, (c) Acknowledge the inherent patchiness of wildfires and the value of unburnt areas and places burnt at low severity as critical refugia for some species; it is critical that these locations are managed accordingly (e.g. by limited additional disturbances within them). Finally, many of the insights discussed in this article have emerged only through long-term studies. More long-term monitoring and research is needed to truly understand and better manage fire in Australian ecosystems.

Preliminary observations on the movement ecology of a crested horn shark (Heterodontus galeatus).

The residency and movements of a single acoustically tagged female crested horn shark (Heterodontus galeatus) were monitored in Jervis Bay, Australia. The individual was intermittently detected by receivers throughout the 8-year study period and showed preference for particular rocky reefs in terms of its residency indices and duration of residency events. This individual exhibited lower residency and dissimilar movement patterns to that of the well-studied and sympatric Port Jackson shark (Heterodontus portusjacksoni), highlighting the need for research into the basic life history and movement ecology of H. galeatus.

Residency and movement patterns of adult Port Jackson sharks (Heterodontus portusjacksoni) at a breeding aggregation site.

Examining the movement ecology of mesopredators is fundamental to developing an understanding of their biology, ecology and behaviour, as well as the communities and ecosystems they influence. The limited research on the residency and movements of benthic marine mesopredators has primarily used visual tags, which do not allow for the efficient and accurate monitoring of individual space use. In this study, the authors investigated the residency and movement patterns of Port Jackson sharks Heterodontus portusjacksoni (Meyer 1793) at a breeding aggregation site in Jervis Bay, south-eastern Australia, using passive acoustic telemetry to further our understanding of the movement ecology of these important mesopredators. Between 2012 and 2014, individuals were tagged with acoustic transmitters, and their residency and movements within the bay were monitored for up to 4 years. H. portusjacksoni showed strong preferences for particular reefs within and between breeding seasons. Males had significantly higher residency indices at their favoured sites relative to females, suggesting that males may be engaging in territorial behaviour. Conversely, female H. portusjacksoni exhibited higher roaming indices relative to males indicating that females may move between sites to assess males. Finally, H. portusjacksoni showed temporal variation in movements between reefs with individuals typically visiting more reefs at night relative to the day, dusk and dawn corresponding with their nocturnal habits.

Sewage: from liability to asset, the shoalhaven REMS project. Australia's largest regional waste water re-cycling scheme that has greatly reduced effluent discharge to sensitive waterways and helped increase dairy farm productivity. An overview of this comparatively simple project after 20 years of initial operation, REMS stages 1A + 1B

Abstract An overview of the REclaimed Water Management Scheme (REMS), Stages 1A &amp; 1B undertaken by Shoalhaven Water, the water utility of Shoalhaven City Council, NSW, Australia, after its first twenty years of operation. REMS is one of the largest recycled effluent projects undertaken by a local government in Australia. REMS utilises tertiary treated re-claimed sewage water from the urban centres and utilises it, in lieu of potable water, for agricultural and sports field irrigation, while diverting discharge away from sensitive waterways. The REMS project was initiated to address three primary issues: Public outcry over sewage discharge into sensitive Bay/River/Ocean environments including Jervis Bay and the Shoalhaven River. To assist the Dairy industry though providing resistance to drought. To upgrade the sewerage system to enable development and address the demands of a greatly increased population. This paper places the scheme in the context of an integrated Water Utility and Local Government body, engaging stakeholders in extensive consultation, and embarking on a large project designed to have significant Environmental and Economic outcomes, culminating in an integrated multi-plant capture, treatment and distribution system. The project is focussed upon agricultural use of recycled water that has wide support public support, and benefits to both the Dairy farmers and Oyster farmers of the region. The paper examines REMS' success, its future expanded capabilities, and its application as a scalable model elsewhere.

Heterarchy Reveals Social Organization of a Smooth Stingray (Bathytoshia brevicaudata) Population in a Provisioned Food Context

The advent of new technologies and statistical analyses has provided valuable insights into chondrichthyan social behavior. It has become apparent that sharks and rays lead more complex social lives than previously believed. Heterarchy combines hierarchy and social network theory and although it is not a new concept, it is rarely applied to animal social interactions. Here, we applied heterarchy to a case study involving smooth stingrays foraging for fish scraps at boat ramp in Jervis Bay, NSW Australia. We took advantage of their attraction to this site to examine their social behavior during agonistic interactions over the provisioned resource. We observed a stable, relatively linear but shallow dominance hierarchy that was highly transitive dominated by a single individual. Social network analysis revealed a non-random social network centered on the dominant individual. Contrary to previous research, size did not predict dominance, but it was correlated with network centrality. The factors determining dominance of lower ranks were difficult to discern, which is characteristic of despotic societies. This study provides the first heterarchical assessment of stingray sociality, and suggests this species is capable of complex social behavior. Given higher dominance and centrality relate to greater access to the provisioned resource, the observed social structure likely has fitness implications.

BASELINE HEALTH PARAMETERS FOR A NEWLY ESTABLISHED POPULATION OF LONG-NOSED POTOROO (POTOROUS TRIDACTYLUS) AT BOODEREE NATIONAL PARK, AUSTRALIA.

Over two field seasons during 2014-15, 35 long-nosed potoroos (Potorous tridactylus) were captured in state forests in South Eastern New South Wales for translocation to Booderee National Park, Jervis Bay Territory, Australia. Animals were anesthetized for physical examination and collection of samples to assess general health and screen for select diseases identified during a disease risk assessment. Morphologic, hematologic, and biochemical parameters were determined, and parasites were identified where possible. Trypanosoma gilletti, Trypanosoma vegrandis, and novel genotypes most similar to a Trypanosoma wallaby-derived isolate (ABF) were identified from blood samples by PCR; the first time Trypanosoma has been described in this species. Also reported is the first confirmation of the Australian paralysis tick, Ixodes holocyclus, from the long-nosed potoroo. Surveillance showed that Cryptococcus sp. may form part of the normal nasal flora for long-nosed potoroo. Salmonella enterica serotype Dublin and Salmonella enterica subsp. enterica was identified from rectal swabs of otherwise healthy animals. The data provide baseline health and disease parameters for this newly established population and the source population and will inform future translocation and conservation management activities. These data expand current knowledge on aspects of the biology and microbiology of the long-nosed potoroo, both locally and nationally.

Population variation in the thermal response to climate change reveals differing sensitivity in a benthic shark

Many species with broad distributions are exposed to different thermal regimes which often select for varied phenotypes. This intraspecific variation is often overlooked but may be critical in dictating the vulnerability of different populations to environmental change. We reared Port Jackson shark (Heterodontus portusjacksoni) eggs from two thermally discrete populations (i.e. Jervis Bay and Adelaide) under each location's present-day mean temperatures, predicted end-of-century temperatures and under reciprocal-cross conditions to establish intraspecific thermal sensitivity. Rearing temperatures strongly influenced ṀO2 Max and critical thermal limits, regardless of population, indicative of acclimation processes. However, there were significant population-level effects, such that Jervis Bay sharks, regardless of rearing temperature, did not exhibit differences in ṀO2 Rest , but under elevated temperatures exhibited reduced maximum swimming activity with step-wise increases in temperature. In contrast, Adelaide sharks reared under elevated temperatures doubled their ṀO2 Rest , relative to their present-day temperature counterparts; however, maximum swimming activity was not influenced. With respect to reciprocal-cross comparisons, few differences were detected between Jervis Bay and Adelaide sharks reared under ambient Jervis Bay temperatures. Similarly, juveniles (from both populations) reared under Adelaide conditions had similar thermal limits and swimming activity (maximum volitional velocity and distance) to each other, indicative of conserved acclimation capacity. However, under Adelaide temperatures, the ṀO2 Rest of Jervis Bay sharks was greater than that of Adelaide sharks. This indicates that the energetics of cooler water population (Adelaide) is likely more thermally sensitive than that of the warmer population (Jervis Bay). While unique to elasmobranchs, these data provide further support that by treating species as static, homogeneous populations, we ignore the impacts of thermal history and intraspecific variation on thermal sensitivity. With climate change, intraspecific variation will manifest as populations move, demographics change or extirpations occur, starting with the most sensitive populations.