ORCID Profile
0000-0003-0291-3180
Current Organisations
Commonwealth Scientific and Industrial Organisation
,
CSIRO
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Publisher: CSIRO
Date: 2016
Publisher: Springer Science and Business Media LLC
Date: 22-03-2021
Publisher: Springer Science and Business Media LLC
Date: 23-06-2020
DOI: 10.1038/S41598-020-66876-Z
Abstract: In Australian and New Zealand waters, current knowledge on white shark ( Carcharodon carcharias ) movement ecology is based on in idual tracking studies using relatively small numbers of tags. These studies describe a species that occupies highly variable and complex habitats. However, uncertainty remains as to whether the proposed movement patterns are representative of the wider population. Here, we tagged 103 immature Australasian white sharks (147–350 cm fork length) with both acoustic and satellite transmitters to expand our current knowledge of population linkages, spatiotemporal dynamics and coastal habitats. Eighty-three sharks provided useable data. Based on in idual tracking periods of up to 5 years and a total of 2,865 days of tracking data, we were able to characterise complex movement patterns over ~45° of latitude and ~72° of longitude and distinguish regular/recurrent patterns from occasional/exceptional migration events. Shark movements ranged from Papua New Guinea to sub-Antarctic waters and to Western Australia, highlighting connectivity across their entire Australasian range. Results over the 12-year study period yielded a comprehensive characterisation of the movement ecology of immature Australasian white sharks across multiple spatial scales and substantially expanded the body of knowledge available for population assessment and management.
Publisher: Wiley
Date: 17-10-2011
DOI: 10.1111/J.1365-2656.2011.01914.X
Abstract: 1. Search processes play an important role in physical, chemical and biological systems. In animal foraging, the search strategy predators should use to search optimally for prey is an enduring question. Some models demonstrate that when prey is sparsely distributed, an optimal search pattern is a specialised random walk known as a Lévy flight, whereas when prey is abundant, simple Brownian motion is sufficiently efficient. These predictions form part of what has been termed the Lévy flight foraging hypothesis (LFF) which states that as Lévy flights optimise random searches, movements approximated by optimal Lévy flights may have naturally evolved in organisms to enhance encounters with targets (e.g. prey) when knowledge of their locations is incomplete. 2. Whether free-ranging predators exhibit the movement patterns predicted in the LFF hypothesis in response to known prey types and distributions, however, has not been determined. We tested this using vertical and horizontal movement data from electronic tagging of an apex predator, the great white shark Carcharodon carcharias, across widely differing habitats reflecting different prey types. 3. In idual white sharks exhibited movement patterns that predicted well the prey types expected under the LFF hypothesis. Shark movements were best approximated by Brownian motion when hunting near abundant, predictable sources of prey (e.g. seal colonies, fish aggregations), whereas movements approximating truncated Lévy flights were present when searching for sparsely distributed or potentially difficult-to-detect prey in oceanic or shelf environments, respectively. 4. That movement patterns approximated by truncated Lévy flights and Brownian behaviour were present in the predicted prey fields indicates search strategies adopted by white sharks appear to be the most efficient ones for encountering prey in the habitats where such patterns are observed. This suggests that C. carcharias appears capable of exhibiting search patterns that are approximated as optimal in response to encountered changes in prey type and abundance, and across erse marine habitats, from the surf zone to the deep ocean. 5. Our results provide some support for the LFF hypothesis. However, it is possible that the observed Lévy patterns of white sharks may not arise from an adaptive behaviour but could be an emergent property arising from simple, straight-line movements between complex (e.g. fractal) distributions of prey. Experimental studies are needed in vertebrates to test for the presence of Lévy behaviour patterns in the absence of complex prey distributions.
Publisher: Springer Science and Business Media LLC
Date: 20-11-2009
Publisher: Springer Science and Business Media LLC
Date: 11-1997
Publisher: Springer Science and Business Media LLC
Date: 18-12-2012
Publisher: Springer Science and Business Media LLC
Date: 08-02-2018
DOI: 10.1038/S41598-018-20593-W
Abstract: Conservation concerns exist for many sharks but robust estimates of abundance are often lacking. Improving population status is a performance measure for species under conservation or recovery plans, yet the lack of data permitting estimation of population size means the efficacy of management actions can be difficult to assess, and achieving the goal of removing species from conservation listing challenging. For potentially dangerous species, like the white shark, balancing conservation and public safety demands is politically and socially complex, often leading to vigorous debate about their population status. This increases the need for robust information to inform policy decisions. We developed a novel method for estimating the total abundance of white sharks in eastern Australia and New Zealand using the genetic-relatedness of juveniles and applying a close-kin mark-recapture framework and demographic model. Estimated numbers of adults are small (ca. 280–650), as is total population size (ca. 2,500–6,750). However, estimates of survival probability are high for adults (over 90%), and fairly high for juveniles (around 73%). This represents the first direct estimate of total white shark abundance and survival calculated from data across both the spatial and temporal life-history of the animal and provides a pathway to estimate population trend.
Publisher: CSIRO
Date: 2021
DOI: 10.25919/D6QD-P002
Publisher: Bentham Science Publishers Ltd.
Date: 08-03-2013
DOI: 10.2174/1874401X01306010013
Abstract: Port Lincoln, South Australia is the departure port for the only white shark, Carcharodon carcharias, cage e industry in Australia. Established in the early 1960’s as a niche tourism venture, the industry has recently undergone a rapid expansion to accommodate greater passenger numbers, more tourism operators, and additional infrastructure aimed at capturing a greater proportion of the tourist dollar. However, to date, there has been no assessment of growth in the industry. We have used the operator logbook system, introduced in 2000, as the basis for a rapid assessment of the maturity as well as a conservative estimate of the economic value of the industry, with a focus on 2011. From the logbook system the number of days on-site has increased from an average of 67 days per year prior to 2007 to 287 days on-site in 2011. In 2011 the industry accommodated approximately 5200 passengers with a direct domestic expenditure estimated to be in excess of 6 million AUD. Changes in shark behaviour have been observed following the increase in days on-site. The white shark cage e industry has reached a stage in its development where increased management is required in order to ensure a viable industry into the future. The rapid assessment technique described herein will allow managers to track changes in cage e participation rates and quickly respond to changes in the industry.
Publisher: JMIR Publications Inc.
Date: 09-07-2020
DOI: 10.2196/16018
Abstract: There is a growing trend in the use of mobile health (mHealth) technologies in traditional Chinese medicine (TCM) and telemedicine, especially during the coronavirus disease (COVID-19) outbreak. Tongue diagnosis is an important component of TCM, but also plays a role in Western medicine, for ex le in dermatology. However, the procedure of obtaining tongue images has not been standardized and the reliability of tongue diagnosis by smartphone tongue images has yet to be evaluated. The first objective of this study was to develop an operating classification scheme for tongue coating diagnosis. The second and main objective of this study was to determine the intra-rater and inter-rater reliability of tongue coating diagnosis using the operating classification scheme. An operating classification scheme for tongue coating was developed using a stepwise approach and a quasi-Delphi method. First, tongue images (n=2023) were analyzed by 2 groups of assessors to develop the operating classification scheme for tongue coating diagnosis. Based on clinicians’ (n=17) own interpretations as well as their use of the operating classification scheme, the results of tongue diagnosis on a representative tongue image set (n=24) were compared. After gathering consensus for the operating classification scheme, the clinicians were instructed to use the scheme to assess tongue features of their patients under direct visual inspection. At the same time, the clinicians took tongue images of the patients with smartphones and assessed tongue features observed in the smartphone image using the same classification scheme. The intra-rater agreements of these two assessments were calculated to determine which features of tongue coating were better retained by the image. Using the finalized operating classification scheme, clinicians in the study group assessed representative tongue images (n=24) that they had taken, and the intra-rater and inter-rater reliability of their assessments was evaluated. Intra-rater agreement between direct subject inspection and tongue image inspection was good to very good (Cohen κ range 0.69-1.0). Additionally, when comparing the assessment of tongue images on different days, intra-rater reliability was good to very good (κ range 0.7-1.0), except for the color of the tongue body (κ=0.22) and slippery tongue fur (κ=0.1). Inter-rater reliability was moderate for tongue coating (Gwet AC2 range 0.49-0.55), and fair for color and other features of the tongue body (Gwet AC2=0.34). Taken together, our study has shown that tongue images collected via smartphone contain some reliable features, including tongue coating, that can be used in mHealth analysis. Our findings thus support the use of smartphones in telemedicine for detecting changes in tongue coating.
Publisher: Informa UK Limited
Date: 06-2005
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/MF99168
Abstract: In May 1996 the biological oceanography of the main yellowfin tuna longline fishing waters off southern New South Wales, Australia, was examined in relation to the catch by the fishery. A warm-core eddy was identified directly east of Eden with a temperature at 250 m depth of 15˚C. At the western edge of this eddy, relatively high levels of fluorescence (chlorophyll a) were recorded together with pigments typical of diatoms, a feature of upwelling communities. The biomass of zooplankton and micronekton was also significantly higher at the western edge of the eddy. Similarly, acoustic data showed relatively high concentrations of backscatter at the margins of the eddy, particularly at the shelf break and slope. These areas had the greatest potential prey biomass a fact supported by the presence of shelf-and slope-associated prey species in the stomachs of yellowfin tuna caught at the same time. Fishery data for yellowfin tuna (Thunnus albacares) captures showed that catch per unit effort was highest along the shelf and shelf break. Examination of yellowfin tuna catch records from 1988 to 1998 from south-eastern Australia showed highest catches in 1996, ~75%of the catch coming from the western edge of the eddy. We conclude that the presence of a warm-core eddy in the area at this time provided a localized but productive area to which the yellowfin were attracted.
Publisher: CSIRO
Date: 2022
DOI: 10.25919/A3RD-8F33
Publisher: CSIRO
Date: 2015
DOI: 10.25919/EJ8F-1Z96
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.MARENVRES.2018.05.005
Abstract: The impact of seismic surveys on the catchability of marine fish is a contentious issue, with some claims that seismic surveys may negatively affect catch rates. However little empirical evidence exists to quantify the impacts or identify the mechanisms of such impact. In this study, we used a 2-D seismic survey in the Gippsland Basin, Bass Strait, Australia in April 2015 as an opportunity to quantify fish behaviour (field-based) and commercial fisheries catch (desktop study) across the region before and after airgun operations. Three species found in abundance (gummy shark, swell shark, tiger flathead) were acoustically tagged and released within one of two acoustic arrays (experimental and control zone) and monitored before, during and after the seismic survey. In the field study, only 35% of the gummy sharks and 30% of the swell sharks were subsequently detected two days after release, suggesting movement outside the study area. Various tagged in iduals returned sporadically over the monitoring period, including during the seismic survey operations. Behaviour consistent with a possible response to the seismic survey operations was observed for flathead which increased their swimming speed during the seismic survey period and changed their diel movement patterns after the survey. We also investigated the potential impacts of the seismic survey on catch rates using Commonwealth fisheries logbook data from Jan 2012-Oct 2015. Fifteen species and two gear types (Danish seine, gillnet) were modelled to examine differences in catch rates before and after the seismic survey. The catch rates in the six months following the seismic survey were significantly different than predicted in nine out of the 15 species examined, with six species (tiger flathead, goatfish, elephantfish, boarfish, broadnose shark and school shark) showing increases in catch following the seismic survey, and three species (gummy shark, red gurnard, and sawshark) showing reductions. With the exception of flathead movement, we found little evidence for consistent behavioural or catch rate changes induced by the seismic survey in the targeted species, although behavioural data were limited because many sharks left the acoustic receiver array prior to the commencement of the seismic survey.
Publisher: Bentham Science Publishers Ltd.
Date: 06-05-2011
Publisher: Inter-Research Science Center
Date: 04-02-2021
DOI: 10.3354/MEPS13572
Abstract: Management of species with wide-ranging migrations is a complex issue, made more challenging when the species is both protected and poses a risk to humans. Understanding the oceanic conditions associated with shark habitat use can help develop mitigation strategies or warning systems that meet both conservation and human safety objectives. Using satellite tracks from 77 juvenile and sub-adult white sharks tagged over 10 yr, we modelled in idual movement patterns using hidden Markov models and applied generalised additive (mixed) models to explore correlations between movement patterns (presence-absence, habitat selection and behavioural state) and oceanographic and bathymetric variables. White sharks used the whole of the continental shelf, down to depths of 350 m on the continental slope. Sharks were present over a wide range of sea surface temperatures (SSTs 10-27°C), with the highest probability of occurring at ~20°C. However, the number of average daily tag positions was greatest when SST was between 14 and 18°C, and sharks were more likely to exhibit area-restricted movement when SST was between ~19 and 23°C. Sharks were more likely to be present and selected habitats in productive areas with moderate to high surface chl a concentrations as well as thermal and productivity fronts. Although mesoscale eddies did not influence the likelihood of in iduals being present in an area, there was a higher density of sharks in cold-core eddies compared to warm-core eddies. This study indicates that white shark presence and dispersal may be linked, perhaps via prey distribution, to oceanic conditions, potentially assisting development of suitable shark bite mitigation strategies.
Publisher: JMIR Publications Inc.
Date: 27-08-2019
Abstract: here is a growing trend in the use of mobile health (mHealth) technologies in traditional Chinese medicine (TCM) and telemedicine, especially during the coronavirus disease (COVID-19) outbreak. Tongue diagnosis is an important component of TCM, but also plays a role in Western medicine, for ex le in dermatology. However, the procedure of obtaining tongue images has not been standardized and the reliability of tongue diagnosis by smartphone tongue images has yet to be evaluated. he first objective of this study was to develop an operating classification scheme for tongue coating diagnosis. The second and main objective of this study was to determine the intra-rater and inter-rater reliability of tongue coating diagnosis using the operating classification scheme. n operating classification scheme for tongue coating was developed using a stepwise approach and a quasi-Delphi method. First, tongue images (n=2023) were analyzed by 2 groups of assessors to develop the operating classification scheme for tongue coating diagnosis. Based on clinicians’ (n=17) own interpretations as well as their use of the operating classification scheme, the results of tongue diagnosis on a representative tongue image set (n=24) were compared. After gathering consensus for the operating classification scheme, the clinicians were instructed to use the scheme to assess tongue features of their patients under direct visual inspection. At the same time, the clinicians took tongue images of the patients with smartphones and assessed tongue features observed in the smartphone image using the same classification scheme. The intra-rater agreements of these two assessments were calculated to determine which features of tongue coating were better retained by the image. Using the finalized operating classification scheme, clinicians in the study group assessed representative tongue images (n=24) that they had taken, and the intra-rater and inter-rater reliability of their assessments was evaluated. ntra-rater agreement between direct subject inspection and tongue image inspection was good to very good (Cohen κ range 0.69-1.0). Additionally, when comparing the assessment of tongue images on different days, intra-rater reliability was good to very good (κ range 0.7-1.0), except for the color of the tongue body (κ=0.22) and slippery tongue fur (κ=0.1). Inter-rater reliability was moderate for tongue coating (Gwet AC2 range 0.49-0.55), and fair for color and other features of the tongue body (Gwet AC2=0.34). aken together, our study has shown that tongue images collected via smartphone contain some reliable features, including tongue coating, that can be used in mHealth analysis. Our findings thus support the use of smartphones in telemedicine for detecting changes in tongue coating.
Publisher: Bentham Science Publishers Ltd.
Date: 17-11-2015
DOI: 10.2174/1874401X01508010023
Abstract: White sharks show a high degree of residency to specific aggregation sites, to which they return regularly over multiple years. Australian research has historically focused on single aggregation areas within each of the southern states where white sharks occur, but other key habitats likely exist and if so, will be important to identify to effectively monitor and protect threatened white shark populations. This study is the first to describe Liguanea Island as a second white shark aggregation site within South Australia, with residency periods and return visits recorded by multiple in iduals. Eight sharks were detected at both Liguanea Island and the other known aggregation area in the state, the Neptune Islands, demonstrating movement between these locations. Sustained residency periods were recorded at both sites, although high periodic site fidelity was apparent with many in iduals showing preference for the location at which they were tagged. In idual differences in site fidelity and residency patterns were found, although two sub-adult in iduals were found to follow similar movement patterns. The implications of white shark movements, and the suggested identification of a second aggregation areas in close proximity are discussed.
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/MF99150
Abstract: The early life histories of the commercially important blue and spotted warehous (Seriolella brama and S. punctata) were examined on the basis of archived ichthyoplankton s les collected over broad areas of southern Australia. Larvae of both species were widely distributed during winter and spring within shelf and slope waters. Larvae of S. brama were recorded from Kangaroo Island, South Australia (SA), to southern New South Wales (NSW). Seriolella punctata larvae were recorded from western Tasmania to southern NSW. Back-calculated spawning dates, based on otolith microstructure, indicated that spawning predominantly occurs during late July and August but that the timing of spawning varies between regions. The abundances of small larvae ( . 0 mm body length) were highest for both species off western Tasmania and southern NSW. No small S. brama larvae were recorded between southern Tasmania and southern NSW, whereas low but consistent numbers of small S. punctata larvae were found between these regions. The data suggest that there are separate spawning areas for S. brama in western and eastern regions of Australia’s South East Fishery. The pattern for S. punctata is less clear, but suggests a more continuous link among populations in south-eastern Australia.
Publisher: Wiley
Date: 12-2015
DOI: 10.1111/JFB.12827
Abstract: The seasonal patterns of occurrence of male and female white sharks Carcharodon carcharias at the Neptune Islands in South Australia were reviewed. Analyses of a 14 year data series indicate that females seasonally aggregate in late autumn and winter coinciding with the maximum in-water availability of lactating female long-nose fur seals and seal pups. During this period, observed male:female sex ratios were similar whereas during late spring and summer, males continued to visit, but females were rarely recorded. There was no evidence for segregation by sex or size at the Neptunes, but the highly focused seasonal pattern of occurrence of females compared with the year-round records of males suggests that there are likely to be differences between the sexes in overall distribution and movement patterns across southern Australia. It is suggested that foraging strategies and prey selection differ between sexes in C. carcharias across the life-history stages represented and that sex-specific foraging strategies may play an important role in structuring movement patterns and the sex ratios observed at such aggregation sites. Differences between sexes in distribution, movement patterns and foraging strategies are likely to have implications for modelling the consequences of fisheries by-catch between regions or jurisdictions and other spatially or temporally discrete anthropogenic effects on C. carcharias populations. Such differences urge for caution when estimating the size of C. carcharias populations based on observations at pinniped colonies due to the likelihood of sex-specific differences in movements and patterns of residency. These differences also suggest a need to account for sex-specific movement patterns and distribution in population and movement models as well as under conservation actions.
Publisher: Springer Science and Business Media LLC
Date: 04-06-2020
DOI: 10.1007/S00227-020-03712-Y
Abstract: Large endothermic pelagic sharks are highly migratory and use habitats spanning a broad range of coastal, neritic and oceanic areas. This study aimed to resolve the current lack of information on the movements and habitat use of white sharks, Carcharodon carcharias , between shelf, slope and oceanic areas located off southwestern Australia. Movement behaviours, spatial distribution patterns and vertical habitat use of juvenile, sub-adult and adult white sharks ranging in size from 1.9 to 5.7 m total length were examined using 43 satellite tags deployed over 15 years. Pop-up satellite archival tags and satellite-linked radio tags collected 3663 days and 109,900 km of tracking data over periods of up to 381 days. We demonstrated sex-based differences in movement and distribution patterns of male (21) and female (19) white sharks. Female dispersal was broader and extended further offshore than males, which largely remained in neritic and gulf habitats. Female white sharks experienced a narrower range of water temperatures ( F = 9.0–19.0 °C M = 10.4–24.8 °C). Despite these subtle differences, both sexes showed an affinity to the Neptune Island Group and the shelf slope canyons of the eastern Great Australian Bight, which are productive and oceanographically complex regions that support known prey of white sharks. This study highlighted that the southern-western Australian population of white sharks use off-shelf habitat to a greater extent than previously identified. Findings have potential implications for: ecological risk assessments of fisheries that operate in these offshore habitats and for monitoring and managing marine protected areas.
Publisher: Springer Science and Business Media LLC
Date: 06-2013
DOI: 10.1038/S41586-019-1444-4
Abstract: Effective ocean management and the conservation of highly migratory species depend on resolving the overlap between animal movements and distributions, and fishing effort. However, this information is lacking at a global scale. Here we show, using a big-data approach that combines satellite-tracked movements of pelagic sharks and global fishing fleets, that 24% of the mean monthly space used by sharks falls under the footprint of pelagic longline fisheries. Space-use hotspots of commercially valuable sharks and of internationally protected species had the highest overlap with longlines (up to 76% and 64%, respectively), and were also associated with significant increases in fishing effort. We conclude that pelagic sharks have limited spatial refuge from current levels of fishing effort in marine areas beyond national jurisdictions (the high seas). Our results demonstrate an urgent need for conservation and management measures at high-seas hotspots of shark space use, and highlight the potential of simultaneous satellite surveillance of megafauna and fishers as a tool for near-real-time, dynamic management.
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/MF14423
Abstract: The lack of independently verifiable estimates of catches and fisheries independent estimates of abundance and fishing mortality are major sources of uncertainty in the management of many fisheries. DNA profiling provides the potential to substantially improve the quality of data for assessments and act as an additional deterrent to illegal, unreported, and unregulated (IUU) fishing. Barriers to the implementation of this technology include cost of s le collection and processing, forensic grade quality control, and the ability to apply undetectable tags. We present the results of a comparison of two current and one new (gene tag tool, GTT) s ling techniques, using the highly valued southern bluefin tuna as an ex le. We demonstrate that fish s led with two techniques are highly unlikely to be recognised as ‘tagged’, whereas one technique was easily recognisable after 73 days. The GTT reduced handling before DNA extraction, whereas both other techniques require additional labour, adding to cost and potential contamination of the evidentiary chain. Evidence of cross-contamination in the Whatman FTA Elute s les suggests they may not be as suitable for at-sea field applications. Two of the three s ling techniques are capable of obtaining high quality tissue s les for stock assessment and chain of custody purposes in a cost-effective and unidentifiable manner.
Publisher: Hobart, Tas., CSIRO Marine and Atmospheric Research
Date: 2009
Publisher: CSIRO Marine and Atmospheric Research
Date: 2011
Publisher: Inter-Research Science Center
Date: 04-06-2019
DOI: 10.3354/MEPS12969
Publisher: CSIRO Marine and Atmospheric Research
Date: 2013
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/MF14065
Abstract: The phyllosoma larva of the southern rock lobster, Jasus edwardsii, is thought to be among the longest larval phases of any planktonic larva, with estimates in the literature ranging from 12 to 24 months. In the present study, we have used an extensive archive of s les (over 2800 s les with 680 phyllosoma) to refine the estimate of the duration of the pelagic phase. The distribution through the year of larval stages suggested that larvae from two separate spawning events were present in any 12-month period. Using regression analysis, we have estimated the duration of the phyllosoma phase to be 547±47.5 days (~18.2±1.6 months). A new model of J. edwardsii phyllosoma development is presented and compared with data on known hatching and settlement patterns. The new model will improve the paramiterisation of stage-specific biophysical models of larval dispersal and regional connectivity, to better inform management of the southern rock lobster fisheries.
Publisher: Springer Science and Business Media LLC
Date: 1999
Publisher: Elsevier BV
Date: 10-2015
Location: Australia
Location: Australia
No related grants have been discovered for Russell Bradford.