Jane E. Williamson

Macquarie University · Department of Biological Sciences

Molecular techniques were employed to investigate genetic structure and diversity in dusky Carcharhinus obscurus and sandbar C. plumbeus sharks in the Indo-Australian region. Tissue samples of 423 C. obscurus and 442 C. plumbeus defined 18 and 11 mtDNA ND4 haplo- types, respectively. For C. obscurus, weak genetic differentiation was detected betwee...

There is increasing interest in how facilitation cascades-nested positive indirect interactions involving at least 3 species-maintain community structure. Here we investigated whether the positive relationship between the kelp Ecklonia radiata and the gastropod Phasianotrochus eximius is mediated by a third species, the sea urchin Holopneustes purp...

Anthropogenic carbon dioxide (CO2) emissions are resulting in increasing absorption of CO2 by the earth‘s oceans, which has led to a decline in ocean pH, a process known as ocean acidification (OA). Evidence suggests that OA may have the potential to affect the distribution and population dynamics of many marine organisms. Early life history proces...

Signals in intraspecific communication should be inherently honest; otherwise the system is prone to collapse. Theory predicts, however, that honest signalling systems are susceptible to invasion by cheats, the extent of which is largely mediated by fear of reprisal. Cuttlefish facultatively change their shape and colour, an ability that evolved to...

Giant clams (Tridacna and Hippopus) are large marine bivalves occupying tropical and subtropical reefs in the Indo‐Pacific. Giant clam populations have declined in many areas of the Indo‐Pacific and continue to be threatened by harvesting and environmental change. The small giant clam (Tridacna maxima) occurs throughout the Indo‐Pacific and has bee...

Quantifying the trophic role of a species is key to understanding its ecology and ecological role. Their trophic role can influence community composition, ecosystem stability, and nutrient transport and cycling between habitats through ingestion, egestion, and excretion, which requires an understanding of species diet and habitat use. Despite the r...

The increase in the use of molecular methodologies in systematics has driven the necessity for a comprehensive understanding of the limitations of different genetic markers. Not every marker is optimal for all species, which has led to multiple approaches in the study of the taxonomy and systematics of polyclad flatworms. The present study evaluate...

The increase in the use of molecular methodologies in systematics has driven the necessity for a comprehensive understanding of the limitations of different genetic markers. Not every marker is optimal for all species, which has led to multiple approaches in the study of the taxonomy and phylogeny of polyclad flatworms. The present study evaluates...

Bluelined goatfish ( Upeneichthys lineatus ) rapidly change their body colour from a white horizontally banded pattern to a seemingly more conspicuous vertically banded red pattern, often when foraging. Given the apparent conspicuousness of the pattern to a range of observers, it seems unlikely that this colour change is used for camouflage and ins...

The Australian cownose ray (Rhinoptera neglecta) is an understudied batoid that occurs along Australia’s north and east coasts. Currently classified as Data Deficient on the IUCN Red List of Threatened Species, major knowledge gaps exist regarding the species’ geographic range, habitat use and the drivers influencing its presence in coastal Austral...

Increasing ocean acidification is a concern due to its potential effects on the growth, development, and survival of early life stages of tuna in oceanic habitats and on the spatial extent of their suitable nursery habitat. To investigate the potential effects of increasing CO 2 on otolith calcification of 9-day old pre-flexion stage yellowfin tuna...

Many animal species can rapidly change their body colouration and patterning, but often the ecological drivers of such changes are unknown. Here, we explored dynamic colour change in the bluelined goatfish, Upeneichthys lineatus , a temperate marine teleost species. Upeneichthus lineatus can change in a matter of seconds, from a uniform white colou...

Context Primary production on coral reefs varies under changing conditions such as light and nutrient availability. This variation causes changes in basal stable isotopes as photosynthetic and nutrient pathways change. Aims This study provides a preliminary baseline of nitrogen (δ15N) and carbon (δ13C) stable isotope profiles in Symbiodinium and ma...

Context Knowledge of sawshark reproductive biology is limited to general parameters such as reproductive mode and litter size. The mating system is currently unknown. Aim To test for multiple paternity in the common (Pristiophorus cirratus) and southern (Pristiophorus nudipinnis) sawshark and investigate the occurrence of hybridisation between thes...

There is a rapid and extensive decline of our marine biodiversity due to human impacts. However, our ability to understand the extent of these effects is hindered by our lack of knowledge of the occurrence and ecology of some species groups. One such group of understudied organisms are marine flatworms of the order Polycladida, a conspicuous compon...

The use of drones to study the behaviours of marine animals is increasing, yet the potential effects of drones on natural behaviours are poorly understood. Here, we assessed if a small consumer drone produced behavioural changes in a ray common to New South Wales, Australia, the estuary stingray (Dasyatis fluviorum). A drone was flown directly abov...

Tetrodotoxin (TTX) is a potent marine neurotoxin that occurs in several Australian phyla, including pufferfish, toadfish, gobies, and the blue-ringed octopus. These animals are partially immune, and TTX is known to bioaccumulate and subject to trophic transfer. As such, it could be more ubiquitously distributed in animals than is currently known. F...

Examination of the spawning and maturity traits of coexisting Platycephalus caeruleopunctatus, Platycephalus grandispinis and Platycephalus richardsoni (Pisces: Platycephalidae) in coastal waters of southeastern Australia identified many commonalities. Each species was gonochoristic, reproductively active for a prolonged period each year, displayed...

The impacts of climate change are expected to have profound effects on the fisheries of the Pacific Ocean, including its tuna fisheries, the largest globally. This study examined the combined effects of climate change on the yellowfin tuna population using the ecosystem model SEAPODYM. Yellowfin tuna fisheries in the Pacific contribute significantl...

Understanding the unique feeding behaviours of oceanic fish, such as marlin, is key to their effective management. Marlin are notoriously difficult to study, however, and the limited research on marlin feeding shows that diet can vary greatly between species and geographic regions. One region where marlin feeding behaviours are particularly poorly...

Australian cownose rays (Rhinoptera neglecta) and whitespotted eagle rays (Aetobatus ocellatus) are large myliobatiform rays that co‐occur off temperate eastern Australia. Here, we performed stable‐isotope analyses (δ¹³C, δ¹⁵N and δ³⁴S) on fin clips of both species to gain insights into their trophic interactions and isotopic niches, and assess the...

Patterns of mother–embryo fractionation of ¹³C and ¹⁵N were assessed for their predictability across three species of batoids caught as by‐catch in south‐eastern Australia. Stable isotope analysis of 24 mothers and their litters revealed that isotope ratios of embryos were significantly different from their corresponding mothers and that the scale...

The 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, confir...

Bluelined goatfish ( Upeneichthys lineatus ) exhibit dynamic body colour changes and transform rapidly from a pale, buff/white, horizontally banded pattern to a conspicuous, vertically striped, red pattern when foraging. This red pattern is potentially an important foraging signal for communication with conspecifics, provided that U. lineatus can d...

The reproductive characteristics of co-occurring freespine flathead, Ratabulus diversidens , and mud flathead, Ambiserrula jugosa , that interact with fisheries across continental shelf waters of eastern Australia were examined. Samples were collected across three depth strata and two locations on a monthly basis over two years. Males of both speci...

In the waters of southeast Australia, two species of sawshark—the common (Pristiophorus cirratus) and southern (Pristiophorus nudipinnis) sawshark—are frequent by-catch in commercial fisheries. While harvesting of both species is currently considered sustainable, there has been no investigation of whether P. cirratus and P. nudipinnis display genet...

Biological invasions are among the biggest threats to freshwater biodiversity. This is increasingly relevant in the Murray-Darling Basin, Australia, particularly since the introduction of the common carp (Cyprinus carpio). This invasive species now occupies up to 90% of fish biomass, with hugely detrimental impacts on native fauna and flora. To add...

Biological invasions are among the biggest threats to freshwater biodiversity. This is increasingly relevant in the Murray-Darling Basin, Australia, particularly since the introduction of the common carp ( Cyprinus carpio ). This invasive species now occupies up to 90% of fish biomass, with hugely detrimental impacts on native fauna and flora. To a...

Prey manipulation through headfirst ingestion is a common foraging tactic in predatory taxa. Sawsharks possess a toothed rostrum that is thought to assist in prey capture, but the process from prey contact to ingestion is unknown. This study provides evidence of headfirst ingestion and possible prey orientation in situ through the use of cone beam...

Revealing the determinants of virome composition is central to placing disease emergence in a broader evolutionary context. Fish are the most species-rich group of vertebrates and so provide an ideal model system to study the factors that shape virome compositions and their evolution. We characterised the viromes of 19 wild-caught species of marine...

Bioturbation of reef sediments aerates the upper sediment layers and releases organic material to benthic communities. Despite being the larger and more conspicuous bioturbators on coral reefs, the value of holothurians (sea cucumbers) to reef ecosystems is less often attributed to their ecosystem services than their value for fisheries. This may b...

The way an animal behaves in its habitat provides insight into its ecological role. As such, collecting robust, accurate datasets in a time-efficient manner is an ever-present pressure for the field of behavioural ecology. Faced with the shortcomings and physical limitations of traditional ground-based data collection techniques, particularly in ma...

Marine invertebrates are promising sources of novel bioactive secondary metabolites, and organisms like sponges, ascidians and nudibranchs are characterised by possessing potent defensive chemicals. Animals that possess chemical defences often advertise this fact with aposematic colouration that potential predators learn to avoid. One seemingly def...

Over the past decade, drones have become a popular tool for wildlife management and research. Drones have shown significant value for animals that were often difficult or dangerous to study using traditional survey methods. In the past five years drone technology has become commonplace for shark research with their use above, and more recently, bel...

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Coastal ecosystems are under threat from a range of anthropogenic impacts that disrupt habitat connectivity and the ability for animals to move within them. Understanding fine-scale animal movement provides insight into how animals are responding to these pressures, and underpins effective ecological management and conservation strategies. This stu...

Determining the geographic range of widely dispersed or migratory marine organisms is notoriously difficult, often requiring considerable costs and typically extensive tagging or exploration programs. While these approaches are accurate and can reveal important information on the species, they are usually conducted on only a small number of individ...

Background Understanding movement patterns of a species is vital for optimising conservation and management strategies. This information is often difficult to obtain in the marine realm for species that regularly occur at depth. The common sawshark (Pristiophorus cirratus) is a small, benthic-associated elasmobranch species that occurs from shallow...

Tilapia lake virus (TiLV) has caused mass mortalities in farmed and wild tilapia with serious economic and ecological consequences. Until recently, this virus was the sole member of the Amnoonviridae, a family within the order Articulavirales comprising segmented negative-sense RNA viruses. We sought to identify additional viruses within the Amnoon...

Tilapia lake virus (TiLV) has caused mass mortalities in farmed and wild tilapia with serious economic and ecological consequences. Until recently, this virus was the sole member of the Amnoonviridae , a family within the order Articulavirales comprising segmented negative-sense RNA viruses. We sought to identify additional viruses within the Amnoo...

Sawsharks (Order: Pristiophoriformes, Family: Pristiophoridae) are a highly distinctive group of sharks, characterized by a tapering saw‐like rostrum with a pair of elongate barbels on the ventral surface. Their unusual characteristics should attract attention; however, very few studies have been dedicated to sawsharks. As a result, our understandi...

Resource partitioning facilitates the coexistence of sympatric species through spatial, temporal and/or trophic strategies. Fishes living in the intertidal zone demonstrate highly adaptive plastic behaviour, including resource partitioning, through spatial and temporal shifts in diet and microhabitat. Although intertidal fish assemblages are influe...

Populations of sharks are declining globally, largely due to fishing pressure. There is a lack of fisheries-independent data on the demographics of many species, particularly those inhabiting deeper waters. The common sawshark (Pristiophorus cirratus) is a benthic-associated shark endemic to southeastern Australia that has been fished for over 90 y...

Background Understanding movement patterns of a species is vital for optimising conservation and management strategies. This information is often difficult to obtain in the marine realm for species that regularly occur at depth. The common sawshark (Pristiophorus cirratus) is a small, benthic associated elasmobranch species that occurs from shallow...

Background Understanding movement patterns of a species is vital for optimising conservation and management strategies. This information is often difficult to obtain in the marine realm for species that regularly occur at depth. The common sawshark (Pristiophorus cirratus) is a small, benthic associated elasmobranch species that occurs from shallow...

Identifying the components of host ecology that promote virus diversity is crucial for our understanding of the drivers of virus evolution and disease emergence. As the most species rich group of vertebrates that exhibit diverse ecologies, fish provide an ideal model system to study the impacts of host ecology on the composition of their viromes. T...

Sawsharks are one of the least well-known groups of sharks globally, yet they are caught in large numbers in south-eastern Australia. In this study we assessed spatiotemporal patterns of distribution of two co-occurring species of sawsharks, namely the common sawshark (Pristiophorus cirratus) and the southern sawshark (Pristiophorus nudipinnis), to...

Capabilities of remotely operated vehicles (ROVs) have increased substantially in the last decade, and mini-ROV designs are now able to conduct visual research frequently conducted by snorkellers or divers in shallow marine environments. There are logistical, financial and experimental benefits of using mini-ROVs over snorkellers or divers, yet the...

We present the complete mitochondrial genome of the Epaulette Shark Hemiscyllium ocellatum, sequenced with 24 primer sets. The 16,728 bp long circular genome consisted of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a non-coding control region. Several protein-coding genes ended with incomplete stop codons (TA- or T–). Phylogenetic ana...

Restricted gene flow and reproductive philopatry are increasingly being described in marine predators such as sharks. However, observing shark reproductive behaviour in situ is problematic because of issues associated with sampling in the marine environment. As such, molecular tools have become fundamental to unravelling complex mating behaviours....

Measures of biodiversity are often hindered by a lack of methodological practices that distinguish cryptic or morphologically similar cohabiting species. This is particularly difficult for marine fishes where direct observations of the ecology and demography of populations are difficult. Dragonets (Foetorepus c.f. calauropomus) were collected as by...

Elasmobranchs make a large contribution to bycatch in commercial trawl fisheries, which reduces the efficiency (and thus profitability of those fisheries), results in injury and mortality of those elasmobranchs, and can lead to unsustainable rates of catches. The development of bycatch reduction devices (BRDs) for elasmobranchs has been hindered, a...

While post-release mortality estimates have been conducted on a range of shark species, the short-term sub-lethal effects of capture, handling and release are poorly known and have been mostly investigated in controlled conditions. In addition, the widely accepted notion that immediate post-release active swimming is an indicator of shark condition...

Determining the small-scale movement patterns of marine vertebrates usually requires invasive active acoustic tagging or in-water monitoring, with the inherent behavioural impacts of those techniques. In addition, these techniques rarely allow direct continuous behavioural assessments or the recording of environmental interactions, especially for h...

Aquaculture is the fastest growing industry worldwide. Aquatic diseases have had enormous economic and environmental impacts in the recent past and the emergence of new aquatic pathogens, particularly viruses, poses a continuous threat. Nevertheless, little is known about the diversity, abundance and evolution of fish viruses. We used a meta-transc...

Establishing behavioural repeatability is important in animal personality research; however, a range of factors can influence repeatability. Experimental design, particularly acclimation time, is important in managing a subject’s stress prior to the onset of behavioural observations. Acclimatisation also ensures we capture “normal” behaviour and pr...

Hydroides is a large and diverse group of calcareous tubeworms (Serpulidae, Annelida) recognised by a distinctive but variable two-tiered operculum. Despite considerable research using several species of Hydroides as models in ecological and biofouling studies, phylogenetic and biogeographic relationships within the genus are still poorly understoo...

Relationships between fish and otolith measurements were analyzed in nine demersal fishes from the north-eastern Tasmanian waters: Foetorepus calauropomus, Trachurus declivis, Parequula melbournensis, Neosebastes scorpaenoides, Platycephalus aurimaculatus, Platycephalus bassensis, Platycephalus conatus, Lepidotrigla mulhalli and Lepidotrigla vaness...

The development of shark vertebrae and the possible drivers of inter- and intra-specific differences in vertebral structure are poorly understood. Shark vertebrae are used to examine life-history traits related to trophic ecology, movement patterns, and the management of fisheries; a better understanding of their development would be beneficial to...

Raw data of signal detections for linear sections across all vertebrae examined in this study. The data also includes other elements that were detectable, but not necessarily detected in significant amounts. (XLSX)

Body size is an important feature of how species interact with their environment, and can influence predation risk, requirements and type of diet consumed, habitat suitability, and susceptibility to environmental pressures. Echinoderms, such as sea urchins, often inhabit areas subjected to wave disturbance and tidal flow, and are able to withstand...

Potential roles of the rostrum of sawsharks (Pristiophoridae), including predation and self-defence, were assessed through a variety of inferential methods. Comparison of microwear on the surface of the rostral teeth of sawsharks and sawfishes (Pristidae) show that microwear patterns are alike and suggest that the elongate rostra in these two elasm...

Bivalve shells are nanocomposite materials, consisting of a wide variety of ultrastructure types of hierarchically structured units of calcium carbonate crystals embedded within an organic scaffold. Although increasingly important as paleoclimate proxy archives, the exact sub-micrometre growth dynamics and the influence of metabolism on bivalve she...

The Port Jackson Shark (Heterodontus portusjacksoni) is an epibenthic, oviparous species endemic to the southern half of Australia. Understanding the genetic structure, ecology and reproductive behaviours of this species is essential for developing appropriate management and conservation strategies. However, research has been hampered due a lack of...

Recent efforts to monitor the health of coral reefs have highlighted the benefits of using structure from motion-based assessments, and despite increasing use of this technique in ecology and geomorphology, no study has attempted to quantify the precision of this technique over time and across different observers. This study determined whether 3D m...