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metal and metalloid concentrations in the tissues of dusky carcharhinus obscurus, sandbar c. plumbeus and white carcharodon carcharias sharks from south-eastern australian waters, and the implications for human consumption.shark fisheries have expanded due to increased demand for shark products. as long-lived apex predators, sharks are susceptible to bioaccumulation of metals and metalloids, and biomagnification of some such as hg, primarily through diet. this may have negative health implications for human consumers. concentrations of hg, as, cd, cu, fe, se and zn were analysed in muscle, liver and fin fibres (ceratotrichia) from dusky carcharhinus obscurus, sandbar carcharhinus plumbeus, and white carcharodon ca ...201525656241
bioaccumulation of pcbs in liver tissue of dusky carcharhinus obscurus, sandbar c. plumbeus and white carcharodon carcharias sharks from south-eastern australian waters.polychlorinated biphenyls (pcbs) are ubiquitous pollutants in the marine environment that are known to accumulate in apex predators such as sharks. liver samples from dusky carcharhinus obscurus, sandbar carcharhinus plumbeus, and white carcharodon carcharias sharks from south-eastern australian waters were analysed for the seven indicator pcbs 28, 52, 101, 118, 138, 153 and 180. median ∑pcbs were significantly higher in white than sandbar sharks (3.35 and 0.36 μg g(-1) lipid, respectively, p=0. ...201526555794
a novel mini-dna barcoding assay to identify processed fins from internationally protected shark species.there is a growing need to identify shark products in trade, in part due to the recent listing of five commercially important species on the appendices of the convention on international trade in endangered species (cites; porbeagle, lamna nasus, oceanic whitetip, carcharhinus longimanus scalloped hammerhead, sphyrna lewini, smooth hammerhead, s. zygaena and great hammerhead s. mokarran) in addition to three species listed in the early part of this century (whale, rhincodon typus, basking, cetor ...201525646789
multiple prismatic calcium phosphate layers in the jaws of present-day sharks (chondrichthyes; selachii).jaws of large individuals, over 2 m in total length, of the shark species carcharodon carcharias (great white shark) and isurus oxyrinchus (mako shark) of the family lamnidae, and galeocerdo cuvieri (tiger shark) and carcharhinus leucas (bull shark) of the family carcharhinidae were found to have multiple, up to five, layers of prismatic calcium phosphate surrounding the cartilages. smaller individuals of these species and other known species of living chondrichthyans have only one layer of pris ...19911999241
a comparison of the heart and muscle total lipid and fatty acid profiles of nine large shark species from the east coast of south africa.we have assessed the fatty acid profiles of the hearts and different muscle tissues from nine large shark species (carcharhinus limbatus (blacktip), carcharhinus obscurus (dusky), carcharhinus brevipinna (spinner), carcharhinus leucas (zambezi/bull), galeocerdo cuvier (tiger), sphyrna lewini (scalloped hammerhead), sphyrna zygaena (smooth hammerhead), carcharodon carcharias (great white) and carcharias taurus (raggedtooth/grey nurse/sand tiger)) found off the east coast of south africa. while th ...201120694746
first reports of proliferative lesions in the great white shark, carcharodon carcharias l., and bronze whaler shark, carcharhinus brachyurus günther. 201425303333
residency, habitat use and sexual segregation of white sharks, carcharodon carcharias in false bay, south africa.white sharks (carcharodon carcharias) are threatened apex predators and identification of their critical habitats and how these are used are essential to ensuring improved local and ultimately global white shark protection. in this study we investigated habitat use by white sharks in false bay, south africa, using acoustic telemetry. 56 sharks (39 female, 17 male), ranging in size from 1.7-5 m tl, were tagged with acoustic transmitters and monitored on an array of 30 receivers for 975 days. to i ...201323383052
comparison of pinniped and cetacean prey tissue lipids with lipids of their elasmobranch predator.the great white shark is known to include pinnipeds and cetaceans in its diet. both groups of marine mammals deposit thick blubber layers around their bodies. elasmobranchs do not produce adipose tissue, but rather store lipid in their livers, thus a great white predating on a marine mammal will deposit the lipids in its liver until required.201424632977
sperm storage in male elasmobranchs: a description and survey.two basic types of spermatozoan aggregates, spermatophores and spermatozeugmata, found in 14 different species of sharks, one species of skate, and one species of chimaera (holocephalan), were investigated using light and scanning electron microscopy. spermatophores, aggregates (usually 1,000-6,000 microns in diameter and larger) of randomly clumped sperm embedded in and surrounded by an eosinophilic matrix, were found in alopias superciliosus, odontaspis taurus, carcharodon carcharias, isurus o ...19948169955
tooth development and histology patterns in lamniform sharks (elasmobranchii, lamniformes) revisited.the dentition of lamniforme sharks exhibits several characters that have been used extensively to resolve the phylogenetic relationships of extant taxa, yet some uncertainties remain. also, the development of different teeth of a tooth file within the jaws of most extant lamniforms has not been documented to date. high-resolution micro-computed tomography is used here to re-evaluate the importance of two dental characters within the order lamniformes, which were considered not to be phylogenetic ...201627587092
dna barcoding of shark meats identify species composition and cites-listed species from the markets in taiwan.an increasing awareness of the vulnerability of sharks to exploitation by shark finning has contributed to a growing concern about an unsustainable shark fishery. taiwan's fleet has the 4th largest shark catch in the world, accounting for almost 6% of the global figures. revealing the diversity of sharks consumed by taiwanese is important in designing conservation plans. however, fins make up less than 5% of the total body weight of a shark, and their bodies are sold as filets in the market, mak ...201324260209
insights using a molecular approach into the life cycle of a tapeworm infecting great white sharks.the great white shark carcharodon carcharias linnaeus, 1758 is a versatile and fierce predator (and responsible for many shark attacks on humans). this apex predator feeds on a wide range of organisms including teleosts, other elasmobranchs, cephalopods, pinnipeds, and cetaceans. although much is known about its diet, no trophic links have been empirically identified as being involved in the transmission of its tapeworm parasites. recently, the use of molecular tools combined with phylogenetics ...201121506792
effects of smart position only (spot) tag deployment on white sharks carcharodon carcharias in south africa.we present 15 individual cases of sub-adult white sharks that were spot tagged in south africa from 2003-2004 and have been re-sighted as recently as 2011. our observations suggest spot tags can cause permanent cosmetic and structural damage to white shark dorsal fins depending on the duration of tag attachment. spot tags that detached within 12-24 months did not cause long term damage to the dorsal fin other than pigmentation scarring. within 12 months of deployment, tag fouling can occur. afte ...201122110620
recovery of human remains after shark attack.two cases of fatal shark attack are reported where the only tissues recovered were fragments of lung. case 1: an 18-year-old male who was in the sea behind a boat was observed by friends to be taken by a great white shark (carcharodon carcharias). the shark dragged him under the water and then, with a second shark, dismembered the body. witnesses noted a large amount of blood and unrecognizable body parts coming to the surface. the only tissues recovered despite an intensive beach and sea search ...200616936505
use of forensic analysis to better understand shark attack behaviour.shark attacks have primarily been analyzed from wound patterns, with little knowledge of a shark's approach, behaviour and intention leading to such wounds. for the first time, during a shark-human interaction project in south africa, a white shark, carcharodon carcharias, was filmed biting a vertically positioned person at the water surface, and exhibiting distinct approach patterns leading to the bite. this bite was compared to ten white shark attacks that occurred (i) in the same geographical ...200416223019
incidence of organochlorine pesticides in muscle and liver tissues of south african great white sharks carcharodon carcharias. 200415737362
isolation and characterization of cxc receptor genes in a range of elasmobranchs.the cxc group of chemokines exert their cellular effects via the cxcr group of g-protein coupled receptors. six cxcr genes have been identified in humans (cxcr1-6), and homologues to some of these have been isolated from a range of vertebrate species. here we isolate and characterize cxcr genes from a range of elasmobranch species. one cxcr1/2 gene fragment isolated from scyliorhinus caniculus (lesser spotted catshark), and two cxcr1/2 copies from each of the elasmobranchs, cetorhinus maximus (b ...200515572071
bacteriology of the teeth from a great white shark: potential medical implications for shark bite victims.bacteria were cultured for the first time from the teeth of a great white shark (carcharodon carcharias). isolates included vibrio alginolyticus, vibrio fluvialis, vibrio parahaemolyticus, and other genera. all are common in the marine environment and some may be associated with wound infections in humans. shark bite lacerations may serve as a source of these potentially infectious bacteria, particularly vibrio spp., and should be treated immediately. antibiotic susceptibility patterns are shown ...19846511869
dental ontogeny of a white shark embryo.unlike most viviparous vertebrates, lamniform sharks develop functional teeth during early gestation. this feature is considered to be related to their unique reproductive mode where the embryo grows to a large size via feeding on nutritive eggs in utero. however, the developmental process of embryonic teeth is largely uninvestigated. we conducted x-ray microcomputed tomography to observe the dentitions of early-, mid-, and full-term embryos of the white shark carcharodon carcharias (lamniformes ...201727889924
convergence in thunniform anatomy in lamnid sharks and jurassic ichthyosaurs.among extinct ichthyosaurs the jurassic forms ichthyosaurus and stenopterygius share a number of anatomical specializations with lamnid sharks, characterized in the white shark, carcharodon carcharias these features allow their inclusion within the mode of high-speed thunniform swimming to which only two other equally distinctive phylogenetic groups belong, tuna and dolphins-a striking testaments to evolutionary convergence. jurassic ichthyosaurs evolved from reptiles that had returned to the se ...201627794535
a "shark encounter": delayed primary closure and prophylactic antibiotic treatment of a great white shark bite.shark bites are rare but sensational injuries that are covered in the lay press but are not well described in the medical literature.201627623219
how great white sharks nourish their embryos to a large size: evidence of lipid histotrophy in lamnoid shark reproduction.the great white shark (carcharodon carcharias) exhibits viviparous and oophagous reproduction. a 4950 mm total length (tl) gravid female accidentally caught by fishermen in the okinawa prefecture, southern japan carried six embryos (543-624 mm tl, three in each uterus). both uteri contained copious amounts of yellowish viscous uterine fluid (over 79.2 litres in the left uterus), nutrient eggs and broken egg cases. the embryos had yolk stomachs that had ruptured, the mean volume of which was appr ...201627635035
extracting dna from 'jaws': high yield and quality from archived tiger shark (galeocerdo cuvier) skeletal material.archived specimens are highly valuable sources of dna for retrospective genetic/genomic analysis. however, often limited effort has been made to evaluate and optimize extraction methods, which may be crucial for downstream applications. here, we assessed and optimized the usefulness of abundant archived skeletal material from sharks as a source of dna for temporal genomic studies. six different methods for dna extraction, encompassing two different commercial kits and three different protocols, ...201627508520
how close is too close? the effect of a non-lethal electric shark deterrent on white shark behaviour.sharks play a vital role in the health of marine ecosystems, but the potential threat that sharks pose to humans is a reminder of our vulnerability when entering the ocean. personal shark deterrents are being marketed as the solution to mitigate the threat that sharks pose. however, the effectiveness claims of many personal deterrents are based on our knowledge of shark sensory biology rather than robust testing of the devices themselves, as most have not been subjected to independent scientific ...201627368059
shark teeth as edged weapons: serrated teeth of three species of selachians.prior to european contact, south pacific islanders used serrated shark teeth as components of tools and weapons. they did this because serrated shark teeth are remarkably effective at slicing through soft tissues. to understand more about the forms and functions of serrated shark teeth, we examined the morphology and histology of tooth serrations in three species: the tiger shark (galeocerdo cuvier), blue shark (prionace glauca), and white shark (carcharodon carcharias). we show that there are t ...201727353190
first histological examination of a neoplastic lesion from a free-swimming white shark, carcharodon carcharias l. 201627075715
dorsal fin in the white shark, carcharodon carcharias: a dynamic stabilizer for fast swimming.transverse sections of the skin in the dorsal fin of the white shark, carcharodon carcharias, tiger shark, galeocerdo cuvier, and spotted raggedtooth shark, carcharias taurus, show large numbers of dermal fiber bundles, which extend from the body into the fin. the bundles are tightly grouped together in staggered formation (not arranged in a straight line or in rows). this arrangement of dermal fibers gives tensile strength without impeding fiber movement. tangential sections indicate that the f ...200515536651
brain size and brain organization of the whale shark, rhincodon typus, using magnetic resonance imaging.very little is known about the brain organization of the suction filter feeder, rhincodon typus, and how it compares to other orectolobiforms in light of its specialization as a plankton-feeder. brain size and overall brain organization was assessed in two specimens of r. typus in relation to both phylogeny and ecology, using magnetic resonance imaging (mri). in comparison to over 60 other chondrichthyan species, r. typus demonstrated a relatively small brain for its body size (expressed in term ...200919729899
mechanics of biting in great white and sandtiger sharks.although a strong correlation between jaw mechanics and prey selection has been demonstrated in bony fishes (osteichthyes), how jaw mechanics influence feeding performance in cartilaginous fishes (chondrichthyes) remains unknown. hence, tooth shape has been regarded as a primary predictor of feeding behavior in sharks. here we apply finite element analysis (fea) to examine form and function in the jaws of two threatened shark species, the great white (carcharodon carcharias) and the sandtiger (c ...201121129747
effect of sample preparation techniques for carbon and nitrogen stable isotope analysis of hydroxyapatite structures in the form of elasmobranch vertebral centra.bulk stable isotope analysis (sia) provides an important tool for the study of animal ecology. elasmobranch vertebral centra can be serially sampled to obtain an isotopic history of an individual over ontogeny. the measured total δ(13)c value, however, may be misinterpreted due to the inclusion of the (13)c-rich inorganic portion. hydrochloric acid (hcl) is commonly used to remove the inorganic portion of hydroxyapatite structures before undertaking sia, but more recently ethylenediaminetetraace ...201424497282
improved estimation of intrinsic growth r(max) for long-lived species: integrating matrix models and allometry.intrinsic population growth rate (r(max)) is an important parameter for many ecological applications, such as population risk assessment and harvest management. however, r(max) can be a difficult parameter to estimate, particularly for long-lived species, for which appropriate life table data or abundance time series are typically not obtainable. we describe a method for improving estimates of r(max) for long-lived species by integrating life-history theory (allometric models) and population-spe ...201627039528
segregation or aggregation? sex-specific patterns in the seasonal occurrence of white sharks carcharodon carcharias at the neptune islands, south australia.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 w ...201526709211
subsurface observations of white shark carcharodon carcharias predatory behaviour using an autonomous underwater vehicle.in this study, an autonomous underwater vehicle (auv) was used to test this technology as a viable tool for directly observing the behaviour of marine animals and to investigate the behaviour, habitat use and feeding ecology of white sharks carcharodon carcharias near guadalupe island off the coast of mexico. during the period 31 october to 7 november 2013, six auv missions were conducted to track one male and three female c. carcharias, ranging in estimated total length (lt ) from 3·9 to 5·7 m, ...201526709209
global versus local causes and health implications of high mercury concentrations in sharks from the east coast of south africa.conservation concern regarding the overharvest of global shark populations for meat and fin consumption largely surrounds documented deleterious ecosystem effects, but may be further supported by improved knowledge of possibly high levels in their edible tissues (particularly meat) of the neurotoxin, methylmercury (ch3hg). for many regions, however, little data exist on shark tissue hg concentrations, and reasons for hg variation within and among species or across regions are poorly understood. ...201626409147
effects of attitudes and demography on public support for endangered species conservation.it is critical for managers to understand how attitudes and demography affect public's preferences for species protection for designing successful conservation projects. 1080 adults in greece were asked to rate pictures of 12 endangered species on aesthetic and negativistic attitudes, and intention to support their conservation. factor analysis identified a group of animals for which respondents indicated high levels of support for their conservation (red deer, loggerhead sea turtle, brown bear, ...201728376425
a novel application of multi-event modeling to estimate class segregation in a highly migratory oceanic vertebrate.spatial segregation of animals by class (i.e., maturity or sex) within a population due to differential rates of temporary emigration (te) from study sites can be an important life history feature to consider in population assessment and management. however, such rates are poorly known; new quantitative approaches to address these knowledge gaps are needed. we present a novel application of multi-event models that takes advantage of two sources of detections to differentiate temporary emigration ...201627912002
fatal tiger shark, galeocerdo cuvier attack in new caledonia erroneously ascribed to great white shark, carcharodon carcharias.to understand the causes and patterns of shark attacks on humans, accurate identification of the shark species involved is necessary. often, the only reliable evidence for this comes from the characteristics of the wounds exhibited by the victim. the present case report is intended as a reappraisal of the luengoni, 2007 case (international shark attack file no. 4299) where a single shark bite provoked the death of a swimmer by haemorrhagic shock. our examination of the wounds on the body of the ...201526048500
mitochondrial genetic structure and matrilineal origin of white sharks, carcharodon carcharias, in the northeastern pacific: implications for their conservation.white sharks (carcharodon carcharias, ws henceforth) are globally and regionally threatened. understanding their patterns of abundance and connectivity, as they relate to habitat use, is central for delineating conservation units and identifying priority areas for conservation. we analyzed mitochondrial data to test the congruence between patterns of genetic connectivity and of individual movements in the northeastern pacific (nep) and to trace the matrilineal origin of immature ws from coastal ...201526034138
risks and advantages of using surface laser photogrammetry on free-ranging marine organisms: a case study on white sharks carcharodon carcharias.this study employed a non-lethal measurement tool, which combined an existing photo-identification technique with a surface, parallel laser photogrammetry technique, to accurately estimate the size of free-ranging white sharks carcharodon carcharias. findings confirmed the hypothesis that surface laser photogrammetry is more accurate than crew-based estimations that utilized a shark cage of known size as a reference tool. furthermore, field implementation also revealed that the photographer's an ...201525903107
a re-evaluation of the size of the white shark (carcharodon carcharias) population off california, usa.white sharks are highly migratory and segregate by sex, age and size. unlike marine mammals, they neither surface to breathe nor frequent haul-out sites, hindering generation of abundance data required to estimate population size. a recent tag-recapture study used photographic identifications of white sharks at two aggregation sites to estimate abundance in "central california" at 219 mature and sub-adult individuals. they concluded this represented approximately one-half of the total abundance ...201424932483
provisional report on diving-related fatalities in australian waters 2008.an individual case review of diving-related deaths, reported as occurring in australia in 2008, was conducted as part of the dan asia-pacific dive fatality reporting project.201323508659
feeding requirements of white sharks may be higher than originally thought.quantifying the energy requirements of animals in nature is critical for understanding physiological, behavioural, and ecosystem ecology; however, for difficult-to-study species such as large sharks, prey intake rates are largely unknown. here, we use metabolic rates derived from swimming speed estimates to suggest that feeding requirements of the world's largest predatory fish, the white shark (carcharodon carcharias), are several times higher than previously proposed. further, our estimates of ...201323503585
seasonal distribution and historic trends in abundance of white sharks, carcharodon carcharias, in the western north atlantic ocean.despite recent advances in field research on white sharks (carcharodon carcharias) in several regions around the world, opportunistic capture and sighting records remain the primary source of information on this species in the northwest atlantic ocean (nwa). previous studies using limited datasets have suggested a precipitous decline in the abundance of white sharks from this region, but considerable uncertainty in these studies warrants additional investigation. this study builds upon previousl ...201424918579
lipid, fatty acid and energy density profiles of white sharks: insights into the feeding ecology and ecophysiology of a complex top predator.lipids are major sources of metabolic energy in sharks and are closely linked to environmental conditions and biological cycles, such as those related to diet, reproduction and migration. in this study, we report for the first time, the total lipid content, lipid class composition and fatty acid profiles of muscle and liver tissue of white sharks, carcharodon carcharias, of various lengths (1.5-3.9 m), sampled at two geographically separate areas off southern and eastern australia. muscle tissue ...201424871223
comparative organochlorine accumulation in two ecologically similar shark species (carcharodon carcharias and carcharhinus obscurus) with divergent uptake based on different life history.trophic position and body mass are traits commonly used to predict organochlorine burdens. sharks, however, have a variety of feeding and life history strategies and metabolize lipid uniquely. because of this diversity, and the lipid-association of organochlorines, the dynamics of organochlorine accumulation in sharks may be predicted ineffectively by stable isotope-derived trophic position and body mass, as is typical for other taxa. the present study compared ontogenetic organochlorine profile ...201525899033
development and microstructure of tooth histotypes in the blue shark, prionace glauca (carcharhiniformes: carcharhinidae) and the great white shark, carcharodon carcharias (lamniformes: lamnidae).elasmobranchs exhibit two distinct arrangements of mineralized tissues in the teeth that are known as orthodont and osteodont histotypes. traditionally, it has been said that orthodont teeth maintain a pulp cavity throughout tooth development whereas osteodont teeth are filled with osteodentine and lack a pulp cavity when fully developed. we used light microscopy, scanning electron microscopy, and high-resolution micro-computed tomography to compare the structure and development of elasmobranch ...201525845614
white sharks exploit the sun during predatory approaches.there is no conclusive evidence of any nonhuman animal using the sun as part of its predation strategy. here, we show that the world's largest predatory fish-the white shark (carcharodon carcharias)-exploits the sun when approaching baits by positioning the sun directly behind them. on sunny days, sharks reversed their direction of approach along an east-west axis from morning to afternoon but had uniformly distributed approach directions during overcast conditions. these results show that white ...201525811089
genetic diversity of white sharks, carcharodon carcharias, in the northwest atlantic and southern africa.the white shark, carcharodon carcharias, is both one of the largest apex predators in the world and among the most heavily protected marine fish. population genetic diversity is in part shaped by recent demographic history and can thus provide information complementary to more traditional population assessments, which are difficult to obtain for white sharks and have at times been controversial. here, we use the mitochondrial control region and 14 nuclear-encoded microsatellite loci to assess wh ...201525762777
direct determination of fatty acids in fish tissues: quantifying top predator trophic connections.fatty acids are a valuable tool in ecological studies because of the large number of unique structures synthesized. they provide versatile signatures that are being increasingly employed to delineate the transfer of dietary material through marine and terrestrial food webs. the standard procedure for determining fatty acids generally involves lipid extraction followed by methanolysis to produce methyl esters for analysis by gas chromatography. by directly transmethylating ~50 mg wet samples and ...201525376156
the complete mitochondrial dna of white shark (carcharodon carcharias) from isla guadalupe, mexico.the isla guadalupe white shark mitochondrial structure is similar to the one previously reported for a white shark individual from taiwan with a total length of 16,745 and 16,742 bp respectively; the base composition of the genomes was as follow a (30.60%), t (28.67%), c (26.86%) and g (13.87%), contains 13 protein-coding genes and 24 trna genes and the non-coding control region. the trna genes range from 70-72 bp. gene order is the same as in other vertebrates and teleosts.201625121830
unprovoked fatal shark attack in lifou island (loyalty islands, new caledonia, south pacific) by a great white shark, carcharodon carcharias.the case of a fatal, unprovoked shark attack is reported and analyzed. the incident took place on the 30th of september 2007, in the lagoon of luengoni bay, lifou island (loyalty islands, new caledonia). a young french woman who was snorkeling was severely bitten on the right thigh and died of hemorrhage. an analysis based in particular on the size and color of the shark, the characteristics of the wounds, and the behavior of the shark before and after the bite suggests that the aggressor was a ...201020606572
feeding and migration habits of white shark carcharodon carcharias (lamniformes: lamnidae) from isla guadalupe inferred by analysis of stable isotopes delta15n and delta13c.stable isotope composition of marine top predator's tissues provides insight information of its trophic ecology and migratory behavior. previous reports have shown that dermal tissues could record longer patterns of hunting and movement. based on this, the aim of this study was to describe the feeding and migratory habits of the white shark from isla guadalupe, using stable isotopic analysis of dermis. we considered a small subset of many possible prey taxa that the sharks could have eaten throu ...201425102646
eating or meeting? cluster analysis reveals intricacies of white shark (carcharodon carcharias) migration and offshore behavior.elucidating how mobile ocean predators utilize the pelagic environment is vital to understanding the dynamics of oceanic species and ecosystems. pop-up archival transmitting (pat) tags have emerged as an important tool to describe animal migrations in oceanic environments where direct observation is not feasible. available pat tag data, however, are for the most part limited to geographic position, swimming depth and environmental temperature, making effective behavioral observation challenging. ...201223144707
ontogenetic and among-individual variation in foraging strategies of northeast pacific white sharks based on stable isotope analysis.there is growing evidence for individuality in dietary preferences and foraging behaviors within populations of various species. this is especially important for apex predators, since they can potentially have wide dietary niches and a large impact on trophic dynamics within ecosystems. we evaluate the diet of an apex predator, the white shark (carcharodon carcharias), by measuring the stable carbon and nitrogen isotope composition of vertebral growth bands to create lifetime records for 15 indi ...201223028766
characterization of the heart transcriptome of the white shark (carcharodon carcharias).the white shark (carcharodon carcharias) is a globally distributed, apex predator possessing physical, physiological, and behavioral traits that have garnered it significant public attention. in addition to interest in the genetic basis of its form and function, as a representative of the oldest extant jawed vertebrate lineage, white sharks are also of conservation concern due to their small population size and threat from overfishing. despite this, surprisingly little is known about the biology ...201324112713
environmental influences on the abundance and sexual composition of white sharks carcharodon carcharias in gansbaai, south africa.the seasonal occurrence of white sharks visiting gansbaai, south africa was investigated from 2007 to 2011 using sightings from white shark cage diving boats. generalized linear models were used to investigate the number of great white sharks sighted per trip in relation to sex, month, sea surface temperature and multivariate el niño/southern oscillation (enso) indices (mei). water conditions are more variable in summer than winter due to wind-driven cold water upwelling and thermocline displace ...201323951111
the influence of environmental variables on the presence of white sharks, carcharodon carcharias at two popular cape town bathing beaches: a generalized additive mixed model.shark attacks on humans are high profile events which can significantly influence policies related to the coastal zone. a shark warning system in south africa, shark spotters, recorded 378 white shark (carcharodon carcharias) sightings at two popular beaches, fish hoek and muizenberg, during 3690 six-hour long spotting shifts, during the months september to may 2006 to 2011. the probabilities of shark sightings were related to environmental variables using binomial generalized additive mixed mod ...201323874668
travelling light: white sharks (carcharodon carcharias) rely on body lipid stores to power ocean-basin scale migration.many species undertake long-distance annual migrations between foraging and reproductive areas. such migrants depend on the efficient packaging, storage and utilization of energy to succeed. a diverse assemblage of organisms accomplishes this through the use of lipid reserves; yet, it remains unclear whether the migrations of elasmobranchs, which include the largest gill breathers on earth, depend on such a mechanism. we examine depth records from pop-up satellite archival tags to discern change ...201323864595
accuracy of using visual identification of white sharks to estimate residency patterns.determining the residency of an aquatic species is important but challenging and it remains unclear what is the best sampling methodology. photo-identification has been used extensively to estimate patterns of animals' residency and is arguably the most common approach, but it may not be the most effective approach in marine environments. to examine this, in 2005, we deployed acoustic transmitters on 22 white sharks (carcharodon carcharias) in mossel bay, south africa to quantify the probability ...201222514662
isolation and characterization of dinucleotide microsatellite loci in the great white shark, carcharodon carcharias. 200010964240
the last frontier: catch records of white sharks (carcharodon carcharias) in the northwest pacific ocean.white sharks are highly migratory apex predators, globally distributed in temperate, sub-tropical, and tropical waters. knowledge of white shark biology and ecology has increased recently based on research at known aggregation sites in the indian, atlantic, and northeast pacific oceans; however, few data are available for the northwest pacific ocean. this study provides a meta-analysis of 240 observations of white sharks from the northwest pacific ocean between 1951 and 2012. records comprise re ...201424740299
forensic implications of the variation in morphology of marginal serrations on the teeth of the great white shark.the teeth of the great white shark have been examined to ascertain whether there is any commonality in the arrangement or number of the marginal serrations (peaks) or, indeed, whether individual sharks have a unique pattern of shapes or size of the peaks. the teeth of the white shark are characteristic in size and shape with serrations along almost the entire mesial and distal margins. this study has revealed no consistent pattern of size or arrangement of the marginal serrations that was suffic ...19969227074
allometric relationships of the dentition of the great white shark, carcharodon carcharias, in forensic investigations of shark attacks.as a result of a systematic morphometric study of shark dentitions, a system of notation for describing the location of shark teeth has been developed and is proposed as a standard to be adopted for use in similar studies in the future. the macroscopic morphology of white shark teeth has been characterised in order to gain quantitative data which might assist in identification of these sharks from bite marks on victims or objects or from shark carcasses. using these data, a nomogram has been dev ...19911814935
western australia coastal shark bites: a risk assessment.as western australia's (wa) government enacts shark bite mitigation, the personal risk of shark bite in wa has not been studied.201424611078
not all sharks are "swimming noses": variation in olfactory bulb size in cartilaginous fishes.olfaction is a universal modality by which all animals sample chemical stimuli from their environment. in cartilaginous fishes, olfaction is critical for various survival tasks including localizing prey, avoiding predators, and chemosensory communication with conspecifics. little is known, however, about interspecific variation in olfactory capability in these fishes, or whether the relative importance of olfaction in relation to other sensory systems varies with regard to ecological factors, su ...201524435575
vertebral bomb radiocarbon suggests extreme longevity in white sharks.conservation and management efforts for white sharks (carcharodon carcharias) remain hampered by a lack of basic demographic information including age and growth rates. sharks are typically aged by counting growth bands sequentially deposited in their vertebrae, but the assumption of annual deposition of these band pairs requires testing. we compared radiocarbon (δ(14)c) values in vertebrae from four female and four male white sharks from the northwestern atlantic ocean (nwa) with reference chro ...201424416189
a novel method for single sample multi-axial nanoindentation of hydrated heterogeneous tissues based on testing great white shark jaws.nanomechanical testing methods that are suitable for a range of hydrated tissues are crucial for understanding biological systems. nanoindentation of tissues can provide valuable insights into biology, tissue engineering and biomimetic design. however, testing hydrated biological samples still remains a significant challenge. shark jaw cartilage is an ideal substrate for developing a method to test hydrated tissues because it is a unique heterogeneous composite of both mineralized (hard) and non ...201324260558
the complete mitochondrial genome of the great white shark, carcharodon carcharias (chondrichthyes, lamnidae).the complete mitochondrial genome of the great white shark having 16,744 bp and including 13 protein-coding genes, 2 ribosomal rna, 22 transfer rna genes, 1 replication origin region and 1 control region. the mitochondrial gene arrangement of the great white shark is the same as the one observed in the most vertebrates. base composition of the genome is a (30.6%), t (28.7%), c (26.9%) and g (13.9%).201423841607
effects of trophic ecology and habitat use on maternal transfer of contaminants in four species of young of the year lamniform sharks.organic contaminant and total mercury concentrations were compared in four species of lamniform sharks over several age classes to examine bioaccumulation patterns and gain insights into trophic ecology. contaminants found in young of the year (yoy) sharks were assumed to be derived from maternal sources and used as a proxy to investigate factors that influence maternal offloading processes. yoy white (carcharodon carcharias) and mako (isurus oxyrinchus) sharks had comparable and significantly h ...201323773783
features and motivation of a fatal attack by a juvenile white shark, carcharodon carcharias, on a young male surfer in new caledonia (south pacific).we present the case of a non provoked fatal shark attack on a 19-year old male surfer in new caledonia. several severe bites removed the right arm and all flesh from the right thigh, provoking a quick hypovolemic shock that was fatal. the information provided by a witness and the analysis of a partial bite on the right calf allowed us to identify a 2.7 m tl (est. length) white shark as responsible for this attack. the features of the attack are consistent with a young predator motivated by hunge ...201323756534
effects of an electric field on white sharks: in situ testing of an electric deterrent.elasmobranchs can detect minute electromagnetic fields, <1 nv cm(-1), using their ampullae of lorenzini. behavioural responses to electric fields have been investigated in various species, sometimes with the aim to develop shark deterrents to improve human safety. the present study tested the effects of the shark shield freedom7™ electric deterrent on (1) the behaviour of 18 white sharks (carcharodon carcharias) near a static bait, and (2) the rates of attacks on a towed seal decoy. in the first ...201323658766
evidence of maternal offloading of organic contaminants in white sharks (carcharodon carcharias).organic contaminants were measured in young of the year (yoy) white sharks (carcharodon carcharias) incidentally caught in southern california between 2005 and 2012 (n = 20) and were found to be unexpectedly high considering the young age and dietary preferences of young white sharks, suggesting these levels may be due to exposure in utero. to assess the potential contributions of dietary exposure to the observed levels, a five-parameter bioaccumulation model was used to estimate the total loads ...201323646154
white sharks (carcharodon carcharias) scavenging on whales and its potential role in further shaping the ecology of an apex predator.scavenging, a result of a temporary pulse of resources, occurs in virtually all ecosystems containing carnivores, and is an important energy transfer pathway that can impact ecosystem structure and function, and this ecological significance has largely been considered from a terrestrial standpoint; however, little is known about the role of scavenging in shaping the behavioral ecology of marine species, specifically apex predators. here we present findings from multiple opportunistic observation ...201323585850
using stable isotope analysis to understand the migration and trophic ecology of northeastern pacific white sharks (carcharodon carcharias).the white shark (carcharodon carcharias) is a wide-ranging apex predator in the northeastern pacific (nep). electronic tagging has demonstrated that white sharks exhibit a regular migratory pattern, occurring at coastal sites during the late summer, autumn and early winter and moving offshore to oceanic habitats during the remainder of the year, although the purpose of these migrations remains unclear. the purpose of this study was to use stable isotope analysis (sia) to provide insight into the ...201222355313
lévy flight and brownian search patterns of a free-ranging predator reflect different prey field characteristics.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 fora ...201222004140
a first estimate of white shark, carcharodon carcharias, abundance off central california.the decline of sharks in the global oceans underscores the need for careful assessment and monitoring of remaining populations. the northeastern pacific is the home range for a genetically distinct clade of white sharks (carcharodon carcharias). little is known about the conservation status of this demographically isolated population, concentrated seasonally at two discrete aggregation sites: central california (cca) and guadalupe island, mexico. we used photo-identification of dorsal fins in a ...201121389017
long-term individual identification and site fidelity of white sharks, carcharodon carcharias, off california using dorsal fins.mark-recapture techniques can be used to estimate white shark (carcharodon carcharias) population abundance. these frameworks are based on assumptions that marks are conserved and animals are present at the sampling location over the entire duration of the study. though these assumptions have been validated across short-time scales for white sharks, long-term studies of population trends are dependent on these assumptions being valid across longer periods. we use 22 years of photographic data fr ...201124391267
antipodean white sharks on a mediterranean walkabout? historical dispersal leads to genetic discontinuity and an endangered anomalous population.the provenance of white sharks (carcharodon carcharias) in the mediterranean is both a conundrum and an important conservation issue. considering this species's propensity for natal philopatry, any evidence that the mediterranean stock has little or no contemporary immigration from the atlantic would suggest that it is extraordinarily vulnerable. to address this issue we sequenced the mitochondrial control region of four rare mediterranean white sharks. unexpectedly, the juvenile sequences were ...201121084352
relative eye size in elasmobranchs.variation in relative eye size was investigated in a sample of 46 species of elasmobranch, 32 species of sharks and 14 species of batoids (skates and rays). to get a measure of eye size relative to body size, eye axial diameter was scaled with body mass using least-squares linear regression, using both raw species data, where species are treated as independent data points, and phylogenetically independent contrasts. residual values calculated for each species, using the regression equations desc ...200717314474
widespread utility of highly informative aflp molecular markers across divergent shark species.population numbers of many shark species are declining rapidly around the world. despite the commercial and conservation significance, little is known on even the most fundamental aspects of their population biology. data collection that relies on direct observation can be logistically challenging with sharks. consequently, molecular methods are becoming increasingly important to obtain knowledge that is critical for conservation and management. here we describe an amplified fragment length poly ...200617150982
taphonomic evidence for high-speed adapted fins in thunniform ichthyosaurs.ichthyosaurs have been compared with the fast-swimming thunniform groups of marine vertebrates, tuna, lamnid sharks, and dolphins, based on similarity of shape of the body and locomotory organs. in addition to shape, high-tensile stiffness of the control surfaces has been shown to be essential in maximizing hydrodynamic efficiency in extant thunniform swimmers. to date, there has been no evidence of a stiffening support system for the dorsal fin and dorsal lobe of the caudal fin in ichthyosaurs, ...200717021914
caudal fin in the white shark, carcharodon carcharias (lamnidae): a dynamic propeller for fast, efficient swimming.the caudal peduncle and caudal fin of carcharodon carcharias together form a dynamic locomotory structure. the caudal peduncle is a highly modified, dorsoventrally compressed and rigid structure that facilitates the oscillations of the caudal fin. its stiffness appears to be principally achieved by a thick layer of adipose tissue ranging from 28-37% of its cross-sectional area, reinforced by cross-woven collagen fibers. numerous overlying layers of collagen fibers of the stratum compactum, orien ...200515795938
caudal fin allometry in the white shark carcharodon carcharias: implications for locomotory performance and ecology.allometric scaling analysis was employed to investigate the consequences of size evolution on hydrodynamic performance and ecology in the white shark carcharodon carcharias. discriminant analysis using the power equation y=ax(b) was negative for caudal fin span (s) versus fork length (fl) in c. carcharias. in contrast in two delphinid species, delphinus capensis and tursiops aduncus, the span of the flukes versus fork length rises in positive allometric fashion, and strong positive allometry of ...200515772806
infrastructure in the electric sense: admittance data from shark hydrogels.elasmobranchs (sharks, skates, and rays) possess an electrosensory system with an infrastructure of canals connecting the electrosensors to the environment. the electrosensors and canals are filled with a uniform hydrogel, but the gel's function has not yet been determined. we present electrical admittance spectra collected from the hydrogel from 0.05 to 100 khz, covering the effective range of the electrosensors. we have taken samples of this gel, postmortem, from triaenodon obesus and carcharo ...200515711967
["lingue di seripi", "serpents' tongues" and "glossopetrae". highlights from the history of popular "cult" medicine in early modern times].in the 16th, 17th and 18th century "glossopetrae", popularly known as "lingue di serpi", found on the mediterranean island of malta, were extensively used for medical purposes as antidotes. these fossil teeth, including specimens of the "carcharodon megalodon" (an extinct variant of the great white shark), were ground to powder or used as amulet pendants and "credence" and exported to pharmacies and shops in various cities of europe. in antiquity, authors like plinius or solinus, excluding any r ...19979333999
ventricle morphology in pelagic elasmobranch fishes.ventricle weights of the warm-bodied great white shark, atlantic shortfin mako, and the common thresher shark (the latter presumed to be warm-bodied) are similar to those of ectothermic blue sharks, sandbar sharks, dusky sharks, tiger sharks and scalloped hammerhead sharks. ventricle muscularity, as estimated by the ratio of cortical to spongy layer thickness, is almost twice as great in the former three species than in the latter elasmobranchs. measurements of ventricular volumes suggest that t ...19852866886
size of the great white shark (carcharodon).the maximum length of 36.5 feet (11.1 meters) attributed to the white shark (carcharodon carcharias) by günther and others is a mistake. examination of the jaws and teeth of the specimen referred to by günther and comparison with the jaws of white sharks of known length revealed a length of about 17 feet ( approximately 5 meters). the largest white shark reliably measured was a 21-foot (6.4-meter) individual from cuba. bites on whale carcasses found off southern australia suggest that white shar ...197317746627
philopatry and migration of pacific white sharks.advances in electronic tagging and genetic research are making it possible to discern population structure for pelagic marine predators once thought to be panmictic. however, reconciling migration patterns and gene flow to define the resolution of discrete population management units remains a major challenge, and a vital conservation priority for threatened species such as oceanic sharks. many such species have been flagged for international protection, yet effective population assessments and ...201019889703
swimming in the deep end of the gene pool: global population structure of an oceanic giant.despite the impression held by some that few biological mysteries remain, even evocative species such as humpback whales (megaptera novaeangliae), white sharks (carcharodon carcharias) and green turtles (chelonia mydas) have poorly documented movement patterns, reproductive strategies and population dynamics despite years of dedicated research. this is largely due to the difficulty of observing wide-ranging marine species over the majority of their life cycle. the advent of powerful tracking dev ...200717944855
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