WorldWideScience

Sample records for grey nurse shark

  1. Grey Nurse Shark ( Carcharias taurus) Diving Tourism: Tourist Compliance and Shark Behaviour at Fish Rock, Australia

    Science.gov (United States)

    Smith, Kirby; Scarr, Mark; Scarpaci, Carol

    2010-11-01

    Humans can dive with critically endangered grey nurse sharks ( Carcharias taurus) along the east coast of Australia. This study investigated both compliance of tourist divers to a code of conduct and legislation and the behaviour of grey nurse sharks in the presence of divers. A total of 25 data collection dives were conducted from December 2008 to January 2009. Grey nurse shark and diver behaviour were documented using 2-min scan samples and continuous observation. The proportion of time spent observing human-shark interactions was 9.4% of total field time and mean human-shark interaction time was 15.0 min. Results were used to gauge the effectiveness of current management practices for the grey nurse shark dive industry at Fish Rock in New South Wales, Australia. Grey nurse shark dive tourists were compliant to stipulations in the code of conduct and legislation (compliance ranged from 88 to 100%). The research detailed factors that may promote compliance in wildlife tourism operations such as the clarity of the stipulations, locality of the target species and diver perceptions of sharks. Results indicated that grey nurse sharks spent the majority of their time milling (85%) followed by active swimming (15%). Milling behaviour significantly decreased in the presence of more than six divers. Distance between sharks and divers, interaction time and number of sharks were not significantly correlated with grey nurse shark school behaviour. Jaw gaping, rapid withdrawal and stiff or jerky movement were the specific behaviours of grey nurse sharks that occurred most frequently and were associated with distance between divers and sharks and the presence of six or more divers. Revision of the number of divers allowed per interaction with a school of grey nurse sharks and further research on the potential impacts that shark-diving tourism may pose to grey nurse sharks is recommended.

  2. Grey nurse shark (Carcharias taurus) diving tourism: Tourist compliance and shark behaviour at Fish Rock, Australia.

    Science.gov (United States)

    Smith, Kirby; Scarr, Mark; Scarpaci, Carol

    2010-11-01

    Humans can dive with critically endangered grey nurse sharks (Carcharias taurus) along the east coast of Australia. This study investigated both compliance of tourist divers to a code of conduct and legislation and the behaviour of grey nurse sharks in the presence of divers. A total of 25 data collection dives were conducted from December 2008 to January 2009. Grey nurse shark and diver behaviour were documented using 2-min scan samples and continuous observation. The proportion of time spent observing human-shark interactions was 9.4% of total field time and mean human-shark interaction time was 15.0 min. Results were used to gauge the effectiveness of current management practices for the grey nurse shark dive industry at Fish Rock in New South Wales, Australia. Grey nurse shark dive tourists were compliant to stipulations in the code of conduct and legislation (compliance ranged from 88 to 100%). The research detailed factors that may promote compliance in wildlife tourism operations such as the clarity of the stipulations, locality of the target species and diver perceptions of sharks. Results indicated that grey nurse sharks spent the majority of their time milling (85%) followed by active swimming (15%). Milling behaviour significantly decreased in the presence of more than six divers. Distance between sharks and divers, interaction time and number of sharks were not significantly correlated with grey nurse shark school behaviour. Jaw gaping, rapid withdrawal and stiff or jerky movement were the specific behaviours of grey nurse sharks that occurred most frequently and were associated with distance between divers and sharks and the presence of six or more divers. Revision of the number of divers allowed per interaction with a school of grey nurse sharks and further research on the potential impacts that shark-diving tourism may pose to grey nurse sharks is recommended.

  3. Nuclear and mitochondrial DNA reveals isolation of imperilled grey nurse shark populations (Carcharias taurus).

    Science.gov (United States)

    Ahonen, H; Harcourt, R G; Stow, A J

    2009-11-01

    Loss of sharks and other upper-trophic marine predators has sparked worldwide concern for the stability of ocean ecosystems. The grey nurse (ragged-tooth or sand tiger) shark (Carcharias taurus) is Vulnerable on a global scale, Critically Endangered in Australia and presumed extinct in parts of its historical range. We used 193 muscle and fin samples collected from six extant populations to assess global mtDNA and microsatellite diversity and the degree of global population genetic structure. Control region mtDNA diversity was low in every population, and two populations (eastern Australia and Japan) contained only a single mtDNA haplotype. Genetic signatures of recent losses of genetic variation were not yet apparent at microsatellite loci, indicating that this low mtDNA variation is not a result of anthropogenic population declines. Population differentiation was substantial between each population pair except Brazil and South Africa, F(ST) values ranged from 0.050 to 0.699 and 0.100 to 1.00 for microsatellite and mitochondrial data respectively. Bayesian analysis clearly partitioned individuals into five of the populations from which they were sampled. Our data imply a low frequency of immigrant exchange among each of these regions and we suggest that each be recognized as a distinct evolutionary significant unit. In contrast to pelagic species such as whale shark and white shark that may cross ocean basins and where cooperative international efforts are necessary for conservation, grey nurse shark, like many coastal species, need to be managed regionally.

  4. Isolation and genetic diversity of endangered grey nurse shark (Carcharias taurus) populations.

    Science.gov (United States)

    Stow, Adam; Zenger, Kyall; Briscoe, David; Gillings, Michael; Peddemors, Victor; Otway, Nicholas; Harcourt, Robert

    2006-06-22

    Anthropogenic impacts are believed to be the primary threats to the eastern Australian population of grey nurse sharks (Carcharias taurus), which is listed as critically endangered, and the most threatened population globally. Analyses of 235 polymorphic amplified fragment length polymorphisms (AFLP) loci and 700 base pairs of mitochondrial DNA control region provide the first account of genetic variation and geographical partitioning (east and west coasts of Australia, South Africa) in C. taurus. Assignment tests, analysis of relatedness and Fst values all indicate that the Australian populations are isolated from South Africa, with negligible migration between the east and west Australian coasts. There are significant differences in levels of genetic variation among regions. Australian C. taurus, particularly the eastern population, has significantly less AFLP variation than the other sampling localities. Further, the eastern Australian sharks possess only a single mitochondrial haplotype, also suggesting a small number of founding individuals. Therefore, historical, rather than anthropogenic processes most likely account for their depauperate genetic variation. These findings have implications for the viability of the eastern Australian population of grey nurse sharks.

  5. The phylogenomic position of the grey nurse shark Carcharias taurus Rafinesque, 1810 (Lamniformes, Odontaspididae) inferred from the mitochondrial genome.

    Science.gov (United States)

    Bowden, Deborah L; Vargas-Caro, Carolina; Ovenden, Jennifer R; Bennett, Michael B; Bustamante, Carlos

    2016-11-01

    The complete mitochondrial genome of the grey nurse shark Carcharias taurus is described from 25 963 828 sequences obtained using Illumina NGS technology. Total length of the mitogenome is 16 715 bp, consisting of 2 rRNAs, 13 protein-coding regions, 22 tRNA and 2 non-coding regions thus updating the previously published mitogenome for this species. The phylogenomic reconstruction inferred from the mitogenome of 15 species of Lamniform and Carcharhiniform sharks supports the inclusion of C. taurus in a clade with the Lamnidae and Cetorhinidae. This complete mitogenome contributes to ongoing investigation into the monophyly of the Family Odontaspididae.

  6. Conservation of the Critically Endangered Eastern Australian Population of the Grey Nurse Shark ( Carcharias taurus) Through Cross-Jurisdictional Management of a Network of Marine-Protected Areas

    Science.gov (United States)

    Lynch, Tim P.; Harcourt, Robert; Edgar, Graham; Barrett, Neville

    2013-12-01

    Between 2001 and 2009, 26 marine-protected areas (MPA) were established on the east Australian seaboard, at least in part, to manage human interactions with a critically endangered population of grey nurse shark, Carcharias taurus. This network is spread across six MPA systems and includes all 19 sites outlined in the National Recovery Plan for C. taurus, though five sites remain open to some forms of fishing. The reserve network has complex cross-jurisdictional management, as the sharks occur in waters controlled by the Australian states of New South Wales (NSW) and Queensland, as well as by the Commonwealth (Federal) government. Jurisdiction is further complicated by fisheries and conservation departments both engaging in management activities within each state. This has resulted in protected area types that include IUCN category II equivalent zones in NSW, Queensland, and Commonwealth marine parks that either overlay or complement another large scaled network of protected sites called critical habitats. Across the network, seven and eight rule permutations for diving and fishing, respectively, are applied to this population of sharks. Besides sites identified by the recovery plan, additional sites have been protected as part of the general development of MPA networks. A case study at one of these sites, which historically was known to be occupied by C. taurus but had been abandoned, appears to shows re-establishment of an aggregation of juvenile and sub-adult sharks. Concurrent with the re-establishment of the aggregation, a local dive operator increased seasonal dive visitation rates at the site fourfold. As a precautionary measure, protection of abandoned sites, which includes nursery and gestating female habitats are options that may assist recovery of the east coast population of C. taurus.

  7. Chemotaxis of nurse shark leukocytes.

    Science.gov (United States)

    Obenauf, S D; Smith, S H

    1985-01-01

    Studies were conducted to determine the ability of leukocytes from the nurse shark to migrate in an in vitro micropore filter chemotaxis assay and to determine optimal assay conditions and suitable attractants for such an assay. A migratory response was seen with several attractants: activated rat serum, activated shark plasma, and a pool of shark complement components. Only the response to activated rat serum was chemotactic, as determined by the checkerboard assay.

  8. No rainbow for grey bamboo sharks: evidence for the absence of colour vision in sharks from behavioural discrimination experiments.

    Science.gov (United States)

    Schluessel, V; Rick, I P; Plischke, K

    2014-11-01

    Despite convincing data collected by microspectrophotometry and molecular biology, rendering sharks colourblind cone monochromats, the question of whether sharks can perceive colour had not been finally resolved in the absence of any behavioural experiments compensating for the confounding factor of brightness. The present study tested the ability of juvenile grey bamboo sharks to perceive colour in an experimental design based on a paradigm established by Karl von Frisch using colours in combination with grey distractor stimuli of equal brightness. Results showed that contrasts but no colours could be discriminated. Blue and yellow stimuli were not distinguished from a grey distractor stimulus of equal brightness but could be distinguished from distractor stimuli of varying brightness. In addition, different grey stimuli were distinguished significantly above chance level from one another. In conclusion, the behavioural results support the previously collected physiological data on bamboo sharks, which mutually show that the grey bamboo shark, like several marine mammals, is a cone monochromate and colourblind.

  9. Necrophagy of a nurse shark (Ginglymostoma cirratum) by tiger sharks (Galeocerdo cuvier)

    OpenAIRE

    Rada, Danilo P; Programa de Pós Graduação em Ciências Biológicas, CCEN, Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil; Burgess, George H; Florida Museum of Natural History University of Florida, Gainesville, Florida, U.S.A.; Rosa, Ricardo S; Departamento de Sistemática e Ecologia, CCEN, Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil.; Gadig, Otto F; Laboratório de Pesquisa em Elasmobrânquios e Nécton Marinho, UNESP, São Vicente, São Paulo, Brazil.

    2015-01-01

    The aim of this study is to report a scavenging event, involving the consumption of a nurse shark, Ginglymostoma cirratum, by tiger sharks, Galeocerdo cuvier, at Fernando de Noronha archipelago, Brazil. Recreational divers found and photographed a bitten nurse shark carcass, just after sighting two tiger sharks near of the site. We estimated the sharks total lengths and discussed aspects of this feeding interaction using of images of forensic analysis. A straight cut on the nurse shark caudal...

  10. Evolutionary immunology. A boost to immunity from nurse sharks.

    Science.gov (United States)

    Parham, P

    1995-07-01

    A study of the nurse shark has revealed a type of rearranging gene that has yet to be seen in mammals; it encodes a secreted 'new antigen receptor' which, unlike shark immunoglobulin, revels in somatic hypermutation.

  11. First Record of the Grey Reef Shark Carcharhinus amblyrhynchos, (Bleeker, 1856 (Carcharhiniformes: Carcharhinidae from the Lakshadweep Sea, India

    Directory of Open Access Journals (Sweden)

    K.V.A. Kumar

    2013-01-01

    Full Text Available The Grey Reef Shark Carcharhinus amblyrhynchos is a moderately sized and fairly stocky species widely distributed in the Indian and Pacific Oceans from Easter Island and as far west as South Africa. In this paper, the first record of Grey reef shark (single specimen female 126cm in Total Length (TL, caught from the Lakshadweep Sea (10o47 N and 72o09 E by drift long line operation at 40m depth is reported.

  12. Genetic structure and signatures of selection in grey reef sharks (Carcharhinus amblyrhynchos).

    Science.gov (United States)

    Momigliano, P; Harcourt, R; Robbins, W D; Jaiteh, V; Mahardika, G N; Sembiring, A; Stow, A

    2017-09-01

    With overfishing reducing the abundance of marine predators in multiple marine ecosystems, knowledge of genetic structure and local adaptation may provide valuable information to assist sustainable management. Despite recent technological advances, most studies on sharks have used small sets of neutral markers to describe their genetic structure. We used 5517 nuclear single-nucleotide polymorphisms (SNPs) and a mitochondrial DNA (mtDNA) gene to characterize patterns of genetic structure and detect signatures of selection in grey reef sharks (Carcharhinus amblyrhynchos). Using samples from Australia, Indonesia and oceanic reefs in the Indian Ocean, we established that large oceanic distances represent barriers to gene flow, whereas genetic differentiation on continental shelves follows an isolation by distance model. In Australia and Indonesia differentiation at nuclear SNPs was weak, with coral reefs acting as stepping stones maintaining connectivity across large distances. Differentiation of mtDNA was stronger, and more pronounced in females, suggesting sex-biased dispersal. Four independent tests identified a set of loci putatively under selection, indicating that grey reef sharks in eastern Australia are likely under different selective pressures to those in western Australia and Indonesia. Genetic distances averaged across all loci were uncorrelated with genetic distances calculated from outlier loci, supporting the conclusion that different processes underpin genetic divergence in these two data sets. This pattern of heterogeneous genomic differentiation, suggestive of local adaptation, has implications for the conservation of grey reef sharks; furthermore, it highlights that marine species showing little genetic differentiation at neutral loci may exhibit patterns of cryptic genetic structure driven by local selection.

  13. Immunoglobulins in the eggs of the nurse shark, Ginglymostoma cirratum.

    Science.gov (United States)

    Haines, Ashley N; Flajnik, Martin F; Rumfelt, Lynn L; Wourms, John P

    2005-01-01

    Elasmobranchs, which include the sharks, skates, and rays, emerged over 450 million years ago and are the oldest vertebrates to possess an adaptive immune system. They have evolved diverse reproductive modes, with a variety of physiological adaptations that enhance reproductive success. The nurse shark, Ginglymostoma cirratum, is an aplacental, viviparous elasmobranch in which the egg and its associated vitelline vasculature are the primary route for maternal-embryonic interactions. During gestation, nurse shark embryos hatch from their eggcases and develop free in the uterus, which is flushed regularly with seawater. Similar to higher vertebrates, embryonic and neonatal nurse sharks possess an immune system that is not fully competent. In birds and bony fishes, maternal immunoglobulins (Ig) stored in the egg during oogenesis confer protective immunity to embryos during gestation. However, early research suggested that such transfer of passive immunity does not occur in sharks. To better understand how elasmobranch embryos are protected from waterborne pathogens during this potentially vulnerable time, we have re-examined the existence of Igs in elasmobranch eggs. Using monoclonal antibodies, we establish the presence of two classes of Igs in nurse shark eggs: 7S IgM and IgNAR. The potential transfer of immunoglobulins from elasmobranch eggs is discussed.

  14. Environmental influences on patterns of vertical movement and site fidelity of grey reef sharks (Carcharhinus amblyrhynchos at aggregation sites.

    Directory of Open Access Journals (Sweden)

    Gabriel M S Vianna

    Full Text Available We used acoustic telemetry to describe the patterns of vertical movement, site fidelity and residency of grey reef sharks (Carcharhinus amblyrhynchos on the outer slope of coral reefs in Palau, Micronesia, over a period of two years and nine months. We tagged 39 sharks (mostly adult females of which 31 were detected regularly throughout the study. Sharks displayed strong inter-annual residency with greater attendance at monitored sites during summer than winter months. More individuals were detected during the day than at night. Mean depths of tagged sharks increased from 35 m in winter to 60 m in spring following an increase in water temperature at 60 m, with maximum mean depths attained when water temperatures at 60 m stabilised around 29°C. Sharks descended to greater depths and used a wider range of depths around the time of the full moon. There were also crepuscular cycles in mean depth, with sharks moving into shallower waters at dawn and dusk each day. We suggest that daily, lunar and seasonal cycles in vertical movement and residency are strategies for optimising both energetic budgets and foraging behaviour. Cyclical patterns of movement in response to environmental variables might affect the susceptibility of reef sharks to fishing, a consideration that should be taken into account in the implementation of conservation strategies.

  15. Environmental influences on patterns of vertical movement and site fidelity of grey reef sharks (Carcharhinus amblyrhynchos) at aggregation sites.

    Science.gov (United States)

    Vianna, Gabriel M S; Meekan, Mark G; Meeuwig, Jessica J; Speed, Conrad W

    2013-01-01

    We used acoustic telemetry to describe the patterns of vertical movement, site fidelity and residency of grey reef sharks (Carcharhinus amblyrhynchos) on the outer slope of coral reefs in Palau, Micronesia, over a period of two years and nine months. We tagged 39 sharks (mostly adult females) of which 31 were detected regularly throughout the study. Sharks displayed strong inter-annual residency with greater attendance at monitored sites during summer than winter months. More individuals were detected during the day than at night. Mean depths of tagged sharks increased from 35 m in winter to 60 m in spring following an increase in water temperature at 60 m, with maximum mean depths attained when water temperatures at 60 m stabilised around 29°C. Sharks descended to greater depths and used a wider range of depths around the time of the full moon. There were also crepuscular cycles in mean depth, with sharks moving into shallower waters at dawn and dusk each day. We suggest that daily, lunar and seasonal cycles in vertical movement and residency are strategies for optimising both energetic budgets and foraging behaviour. Cyclical patterns of movement in response to environmental variables might affect the susceptibility of reef sharks to fishing, a consideration that should be taken into account in the implementation of conservation strategies.

  16. Melanoma in the skin of a nurse shark (Ginglymostoma cirratum).

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    Waldoch, Jennifer A; Burke, Sandy S; Ramer, Jan C; Garner, Michael M

    2010-12-01

    A female nurse shark, Ginglymostoma cirratum, estimated at 27 yr of age had a 5.5-yr history of a 6-cm black, raised nodular skin lesion located on the right side of the proximal tail. The lesion was diagnosed on biopsy as a slow-growing melanoma of the skin with no vascular invasion. The nurse shark was euthanized for systemic illness approximately 4.5 mo after diagnosis of the dermal melanoma. No evidence of metastasis was found on histopathologic evaluation of the skin and viscera.

  17. Clinical nursing and midwifery research: grey literature in African countries.

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    Sun, C; Dohrn, J; Omoni, G; Malata, A; Klopper, H; Larson, E

    2016-03-01

    This study reviewed grey literature to assess clinical nursing and midwifery research conducted in southern and eastern African countries over the past decade. The shortage of published nursing research from African countries severely limits the ability of practicing nurses and midwives to base clinical decisions on solid evidence. However, little is known regarding unpublished or unindexed clinical research ('grey literature'), a potentially rich source of information. Identifying these sources may reveal resources to assist nurses in providing evidence-based care. This scoping review of grey literature on clinical nursing and midwifery research in southern and eastern African countries helped to identify gaps in research and assess whether these gaps differ from published research. Systematic searches of grey literature were performed. Research was included if it was conducted by nurses in 1 of 25 southern or eastern African countries, between 2004 and 2014 and included patient outcomes. Data were extracted on location, institution, research topic, institutional connections and author information. Chi-square tests were performed to compare differences between indexed and non-indexed literature. We found 262 studies by 287 authors from 17 southern and eastern African countries covering 13 topics. Although all topics were also found in indexed literature and there were statistically significant differences between the number of times, fewer topics were covered in grey literature vs. indexed. Patient satisfaction and experience and traditional health practices were more likely to be published, whereas chronic disease, assault and paediatric-related research were less often published. Generally, there is a paucity of clinical nursing research in this region. This could reflect the shortage of nurses prepared to conduct research in this region. Nurses may find additional resources for evidence in the grey literature. A complete understanding of the state of nursing

  18. Shark immunity bites back: affinity maturation and memory response in the nurse shark, Ginglymostoma cirratum.

    Science.gov (United States)

    Dooley, Helen; Flajnik, Martin F

    2005-03-01

    The cartilaginous fish are the oldest phylogenetic group in which all of the molecular components of the adaptive immune system have been found. Although early studies clearly showed that sharks could produce an IgM-based response following immunization, evidence for memory, affinity maturation and roles for the other isotypes (notably IgNAR) in this group remained inconclusive. The data presented here illustrate that the nurse shark (Ginglymostoma cirratum) is able to produce not only an IgM response, but we also show for the first time a highly antigen-specific IgNAR response. Additionally, under appropriate conditions, a memory response for both isotypes can be elicited. Analysis of the response shows differential expression of pentameric and monomeric IgM. Pentameric IgM provides the 'first line of defense' through high-avidity, low-affinity interaction with antigen. In contrast, monomeric IgM and IgNAR seem responsible for the specific, antigen-driven response. We propose the presence of distinct lineages of B cells in sharks. As there is no conventional isotype switching, each lineage seems pre-determined to express a single isotype (IgM versus IgNAR). However, our data suggest that there may also be specific lineages for the different forms (pentameric versus monomeric) of the IgM isotype.

  19. Effects of Including Misidentified Sharks in Life History Analyses: A Case Study on the Grey Reef Shark Carcharhinus amblyrhynchos from Papua New Guinea.

    Science.gov (United States)

    Smart, Jonathan J; Chin, Andrew; Baje, Leontine; Green, Madeline E; Appleyard, Sharon A; Tobin, Andrew J; Simpfendorfer, Colin A; White, William T

    2016-01-01

    Fisheries observer programs are used around the world to collect crucial information and samples that inform fisheries management. However, observer error may misidentify similar-looking shark species. This raises questions about the level of error that species misidentifications could introduce to estimates of species' life history parameters. This study addressed these questions using the Grey Reef Shark Carcharhinus amblyrhynchos as a case study. Observer misidentification rates were quantified by validating species identifications using diagnostic photographs taken on board supplemented with DNA barcoding. Length-at-age and maturity ogive analyses were then estimated and compared with and without the misidentified individuals. Vertebrae were retained from a total of 155 sharks identified by observers as C. amblyrhynchos. However, 22 (14%) of these were sharks were misidentified by the observers and were subsequently re-identified based on photographs and/or DNA barcoding. Of the 22 individuals misidentified as C. amblyrhynchos, 16 (73%) were detected using photographs and a further 6 via genetic validation. If misidentified individuals had been included, substantial error would have been introduced to both the length-at-age and the maturity estimates. Thus validating the species identification, increased the accuracy of estimated life history parameters for C. amblyrhynchos. From the corrected sample a multi-model inference approach was used to estimate growth for C. amblyrhynchos using three candidate models. The model averaged length-at-age parameters for C. amblyrhynchos with the sexes combined were L∞ = 159 cm TL and L0 = 72 cm TL. Females mature at a greater length (l50 = 136 cm TL) and older age (A50 = 9.1 years) than males (l50 = 123 cm TL; A50 = 5.9 years). The inclusion of techniques to reduce misidentification in observer programs will improve the results of life history studies and ultimately improve management through the use of more accurate data

  20. Isolation and characterization of fatty acid binding protein in the liver of the nurse shark, Ginglymostoma cirratum.

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    Bass, N M; Manning, J A; Luer, C A

    1991-01-01

    1. A 14.5 kDa fatty acid binding protein was isolated from the liver of the nurse shark, Ginglymostoma cirratum. 2. Purified shark liver FABP (pI = 5.4) bound oleic acid at a single site with an affinity similar to that of mammalian FABP. 3. The apparent size, pI and amino acid composition of shark liver FABP indicate a close structural relationship between this protein and mammalian heart FABP.

  1. Visual discrimination following partial telencephalic ablations in nurse sharks (Ginglymostoma cirratum).

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    Graeber, R C; Schroeder, D M; Jane, J A; Ebbesson, S O

    1978-07-15

    An instrumental conditioning task was used to examine the role of the nurse shark telencephalon in black-white (BW) and horizontal-vertical stripes (HV) discrimination performance. In the first experiment, subjects initially received either bilateral anterior telencephalic control lesions or bilateral posterior telencephalic lesions aimed at destroying the central telencephalic nuclei (CN), which are known to receive direct input from the thalamic visual area. Postoperatively, the sharks were trained first on BW and then on HV. Those with anterior lesions learned both tasks as rapidly as unoperated subjects. Those with posterior lesions exhibited visual discrimination deficits related to the amount of damage to the CN and its connecting pathways. Severe damage resulted in an inability to learn either task but caused no impairments in motivation or general learning ability. In the second experiment, the sharks were first trained on BW and HV and then operated. Suction ablations were used to remove various portions of the CN. Sharks with 10% or less damage to the CN retained the preoperatively acquired discriminations almost perfectly. Those with 11-50% damage had to be retrained on both tasks. Almost total removal of the CN produced behavioral indications of blindness along with an inability to perform above the chance level on BW despite excellent retention of both discriminations over a 28-day period before surgery. It appears, however, that such sharks can still detect light. These results implicate the central telencephalic nuclei in the control of visually guided behavior in sharks.

  2. Long-term changes in species composition and relative abundances of sharks at a provisioning site.

    Science.gov (United States)

    Brunnschweiler, Juerg M; Abrantes, Kátya G; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier) displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas) of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004-2006 and 2007-2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004-2006 and very rare in the period of 2007-2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive exclusion among shark

  3. Long-term changes in species composition and relative abundances of sharks at a provisioning site.

    Directory of Open Access Journals (Sweden)

    Juerg M Brunnschweiler

    Full Text Available Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004-2006 and 2007-2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004-2006 and very rare in the period of 2007-2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive

  4. J chain in the nurse shark: implications for function in a lower vertebrate.

    Science.gov (United States)

    Hohman, Valerie S; Stewart, Sue E; Rumfelt, Lynn L; Greenberg, Andrew S; Avila, David W; Flajnik, Martin F; Steiner, Lisa A

    2003-06-15

    J chain is a small polypeptide covalently attached to polymeric IgA and IgM. In humans and mice, it plays a role in binding Ig to the polymeric Ig receptor for transport into secretions. The putative orthologue of mammalian J chain has been identified in the nurse shark by sequence analysis of cDNA and the polypeptide isolated from IgM. Conservation with J chains from other species is relatively poor, especially in the carboxyl-terminal portion, and, unlike other J chains, the shark protein is not acidic. The only highly conserved segment in all known J chains is a block of residues surrounding an N-linked glycosylation site. Of the eight half-cystine residues that are conserved in mammalian J chains, three are lacking in the nurse shark, including two in the carboxyl-terminal segment that have been reported to be required for binding of human J chain-containing IgA to secretory component. Taken together with these data, the relative abundance of J chain transcripts in the spleen and their absence in the spiral valve (intestine) suggest that J chain in nurse sharks may not have a role in Ig secretion. Analysis of J chain sequences in diverse species is in agreement with accepted phylogenetic relationships, with the exception of the earthworm, suggesting that the reported presence of J chain in invertebrates should be reassessed.

  5. The generation and selection of single-domain, v region libraries from nurse sharks.

    Science.gov (United States)

    Flajnik, Martin F; Dooley, Helen

    2009-01-01

    The cartilaginous fish (sharks, skates, and rays) are the oldest phylogenetic group in which a human-type adaptive immune system and immunoglobulins (Igs) have been found. In addition to their conventional (heavy-light chain heterodimeric) isotypes, IgM and IgW, sharks produce the novel isotype, IgNAR, a heavy chain homodimer that does not associate with light chains. Instead, its variable (V) regions act as independent, soluble units in order to bind antigen. In this chapter, we detail our immunization protocol in order to raise a humoral IgNAR response in the nurse shark (Ginglymostoma cirratum) and the subsequent cloning of the single-domain V regions from this isotype in order to select antigen-specific binders by phage display.

  6. Purification and characterization of creatine kinase isozymes from the nurse shark Ginglymostoma cirratum.

    Science.gov (United States)

    Gray, K A; Grossman, S H; Summers, D D

    1986-01-01

    Creatine kinase from nurse shark brain and muscle has been purified to apparent homogeneity. In contrast to creatine kinases from most other vertebrate species, the muscle isozyme and the brain isozyme from nurse shark migrate closely in electrophoresis and, unusually, the muscle isozyme is anodal to the brain isozyme. The isoelectric points are 5.3 and 6.2 for the muscle and brain isozymes, respectively. The purified brain preparation also contains a second active protein with pI 6.0. The amino acid content of the muscle isozyme is compared with other isozymes of creatine kinase using the Metzger Difference Index as an estimation of compositional relatedness. All comparisons show a high degree of compositional similarity including arginine kinase from lobster muscle. The muscle isozyme is marginally more resistant to temperature inactivation than the brain isozyme; the muscle protein does not exhibit unusual stability towards high concentrations of urea. Kinetic analysis of the muscle isozyme reveals Michaelis constants of 1.6 mM MgATP, 12 mM creatine, 1.2 mM MgADP and 50 mM creatine phosphate. Dissociation constants for the same substrate from the binary and ternary enzyme-substrate complex do not differ significantly, indicating limited cooperatively in substrate binding. Enzyme activity is inhibited by small planar anions, most severely by nitrate. Shark muscle creatine kinase hybridizes in vitro with rabbit muscle or monkey brain creatine kinase; shark brain isozyme hybridizes with monkey brain or rabbit brain creatine kinase. Shark muscle and shark brain isozymes, under a wide range of conditions, failed to produce a detectable hybrid.

  7. Construction of a nurse shark (Ginglymostoma cirratum) bacterial artificial chromosome (BAC) library and a preliminary genome survey.

    Science.gov (United States)

    Luo, Meizhong; Kim, Hyeran; Kudrna, Dave; Sisneros, Nicholas B; Lee, So-Jeong; Mueller, Christopher; Collura, Kristi; Zuccolo, Andrea; Buckingham, E Bryan; Grim, Suzanne M; Yanagiya, Kazuyo; Inoko, Hidetoshi; Shiina, Takashi; Flajnik, Martin F; Wing, Rod A; Ohta, Yuko

    2006-05-03

    Sharks are members of the taxonomic class Chondrichthyes, the oldest living jawed vertebrates. Genomic studies of this group, in comparison to representative species in other vertebrate taxa, will allow us to theorize about the fundamental genetic, developmental, and functional characteristics in the common ancestor of all jawed vertebrates. In order to obtain mapping and sequencing data for comparative genomics, we constructed a bacterial artificial chromosome (BAC) library for the nurse shark, Ginglymostoma cirratum. The BAC library consists of 313,344 clones with an average insert size of 144 kb, covering ~4.5 x 1010 bp and thus providing an 11-fold coverage of the haploid genome. BAC end sequence analyses revealed, in addition to LINEs and SINEs commonly found in other animal and plant genomes, two new groups of nurse shark-specific repetitive elements, NSRE1 and NSRE2 that seem to be major components of the nurse shark genome. Screening the library with single-copy or multi-copy gene probes showed 6-28 primary positive clones per probe of which 50-90% were true positives, demonstrating that the BAC library is representative of the different regions of the nurse shark genome. Furthermore, some BAC clones contained multiple genes, making physical mapping feasible. We have constructed a deep-coverage, high-quality, large insert, and publicly available BAC library for a cartilaginous fish. It will be very useful to the scientific community interested in shark genomic structure, comparative genomics, and functional studies. We found two new groups of repetitive elements specific to the nurse shark genome, which may contribute to the architecture and evolution of the nurse shark genome.

  8. Construction of a nurse shark (Ginglymostoma cirratum bacterial artificial chromosome (BAC library and a preliminary genome survey

    Directory of Open Access Journals (Sweden)

    Inoko Hidetoshi

    2006-05-01

    Full Text Available Abstract Background Sharks are members of the taxonomic class Chondrichthyes, the oldest living jawed vertebrates. Genomic studies of this group, in comparison to representative species in other vertebrate taxa, will allow us to theorize about the fundamental genetic, developmental, and functional characteristics in the common ancestor of all jawed vertebrates. Aims In order to obtain mapping and sequencing data for comparative genomics, we constructed a bacterial artificial chromosome (BAC library for the nurse shark, Ginglymostoma cirratum. Results The BAC library consists of 313,344 clones with an average insert size of 144 kb, covering ~4.5 × 1010 bp and thus providing an 11-fold coverage of the haploid genome. BAC end sequence analyses revealed, in addition to LINEs and SINEs commonly found in other animal and plant genomes, two new groups of nurse shark-specific repetitive elements, NSRE1 and NSRE2 that seem to be major components of the nurse shark genome. Screening the library with single-copy or multi-copy gene probes showed 6–28 primary positive clones per probe of which 50–90% were true positives, demonstrating that the BAC library is representative of the different regions of the nurse shark genome. Furthermore, some BAC clones contained multiple genes, making physical mapping feasible. Conclusion We have constructed a deep-coverage, high-quality, large insert, and publicly available BAC library for a cartilaginous fish. It will be very useful to the scientific community interested in shark genomic structure, comparative genomics, and functional studies. We found two new groups of repetitive elements specific to the nurse shark genome, which may contribute to the architecture and evolution of the nurse shark genome.

  9. Expression, purification, crystallization and preliminary X-ray diffraction analysis of nurse shark β2-microglobulin

    OpenAIRE

    Lu, Shuangshuang; Yao, Shugang; Chen, Rong; Zhang, Nianzhi; Chen, Jianmin; Gao, Feng; Xia, Chun

    2012-01-01

    A crystal of nurse shark β2-microglobulin diffracted to 2.3 Å resolution and belonged to space group P3221, with unit-cell parameters a = b = 88.230, c = 67.146 Å and two molecules per asymmetric unit. The Matthews coefficient V M was calculated to be about 3.28 Å3 Da−1, corresponding to 62.5% solvent content.

  10. Reef sharks: recent advances in ecological understanding to inform conservation.

    Science.gov (United States)

    Osgood, G J; Baum, J K

    2015-12-01

    Sharks are increasingly being recognized as important members of coral-reef communities, but their overall conservation status remains uncertain. Nine of the 29 reef-shark species are designated as data deficient in the IUCN Red List, and three-fourths of reef sharks had unknown population trends at the time of their assessment. Fortunately, reef-shark research is on the rise. This new body of research demonstrates reef sharks' high site restriction, fidelity and residency on coral reefs, their broad trophic roles connecting reef communities and their high population genetic structure, all information that should be useful for their management and conservation. Importantly, recent studies on the abundance and population trends of the three classic carcharhinid reef sharks (grey reef shark Carcharhinus amblyrhynchos, blacktip reef shark Carcharhinus melanopterus and whitetip reef shark Triaenodon obesus) may contribute to reassessments identifying them as more vulnerable than currently realized. Because over half of the research effort has focused on only these three reef sharks and the nurse shark Ginglymostoma cirratum in only a few locales, there remain large taxonomic and geographic gaps in reef-shark knowledge. As such, a large portion of reef-shark biodiversity remains uncharacterized despite needs for targeted research identified in their red list assessments. A research agenda for the future should integrate abundance, life history, trophic ecology, genetics, habitat use and movement studies, and expand the breadth of such research to understudied species and localities, in order to better understand the conservation requirements of these species and to motivate effective conservation solutions. © 2015 The Fisheries Society of the British Isles.

  11. Somatic hypermutation and junctional diversification at Ig heavy chain loci in the nurse shark.

    Science.gov (United States)

    Malecek, Karolina; Brandman, Julie; Brodsky, Jennie E; Ohta, Yuko; Flajnik, Martin F; Hsu, Ellen

    2005-12-15

    We estimate there are approximately 15 IgM H chain loci in the nurse shark genome and have characterized one locus. It consists of one V, two D, and one J germline gene segments, and the constant (C) region can be distinguished from all of the others by a unique combination of restriction endonuclease sites in Cmu2. On the basis of these Cmu2 markers, 22 cDNA clones were selected from an epigonal organ cDNA library from the same individual; their C region sequences proved to be the same up to the polyadenylation site. With the identification of the corresponding germline gene segments, CDR3 from shark H chain rearrangements could be analyzed precisely, for the first time. Considerable diversity was generated by trimming and N addition at the three junctions and by varied recombination patterns of the two D gene segments. The cDNA sequences originated from independent rearrangements events, and most carried both single and contiguous substitutions. The 53 point mutations occurred with a bias for transition changes (53%), whereas the 78 tandem substitutions, mostly 2-4 bp long, do not (36%). The nature of the substitution patterns is the same as for mutants from six loci of two nurse shark L chain isotypes, showing that somatic hypermutation events are very similar at both H and L chain genes in this early vertebrate. The cis-regulatory elements targeting somatic hypermutation must have already existed in the ancestral Ig gene, before H and L chain divergence.

  12. Partial migration of the nurse shark, Ginglymostoma cirratum (Bonnaterre), from the Dry Tortugas Islands

    Science.gov (United States)

    Pratt, Harold L.; Pratt, Theo C.; Morley, Danielle; Lowerre-Barbieri, Susan K.; Collins, Angela; Carrier, Jeffrey C.; Hart, Kristen M.; Whitney, N.M.

    2018-01-01

    Nurse sharks have not previously been known to migrate. Nurse sharks of the Dry Tortugas (DRTO) mating population have a highly predictable periodic residency cycle, returning to the Dry Tortugas Courtship and Mating Ground (DTCMG) annually (males) or bi- to triennially (females) during the June/July mating season. For 23 years we have followed the movements of 76 recaptured adults of a total of 115 tagged adults. Telemetry detections of 40 females tagged with acoustic transmitters show that most tagged and presumably post-partum females are continuously present in the DRTO in the fall, winter and early spring following the June mating season but these females depart in late March to early May. Detections reveal these females avoid the DTCMG completely during the next mating season, returning from late summer to fall. Telemetry records of nine of 17 adult males that co-habited with these females in the DTCMG depart DRTO waters every July. Both sexes may overwinter in the DRTO. Between 2011 and 2016 three males and five females with transmitters were detected to move up the west coast of Florida outside of the mating season as far north as the waters off Tampa Bay (335 km). Six others were only detected in the lower Florida Keys (292 km). Nine sharks returned to DRTO; one returned six times. Some overwintered and some resumed courtship in June, demonstrating both resident and migratory contingents within their population, partial migration and an ability to navigate with high spatial and temporal precision.

  13. Expression, purification, crystallization and preliminary X-ray diffraction analysis of nurse shark β2-microglobulin

    International Nuclear Information System (INIS)

    Lu, Shuangshuang; Yao, Shugang; Chen, Rong; Zhang, Nianzhi; Chen, Jianmin; Gao, Feng; Xia, Chun

    2012-01-01

    A crystal of nurse shark β 2 -microglobulin diffracted to 2.3 Å resolution and belonged to space group P3 2 21, with unit-cell parameters a = b = 88.230, c = 67.146 Å and two molecules per asymmetric unit. The Matthews coefficient V M was calculated to be about 3.28 Å 3 Da −1 , corresponding to 62.5% solvent content. β 2 -Microglobulin (β 2 m) is an essential subunit of the major histocompatibility complex (MHC) class I molecule that helps to stabilize the structure of peptide–MHC I (pMHC I). It is also one of the typical immunoglobulin superfamily (IgSF) molecules in the adaptive immune system (AIS). Sharks belong to the cartilaginous fish, which are the oldest jawed vertebrate ancestors with an AIS to exist in the world. Thus, the study of cartilaginous fish β 2 m would help in understanding the evolution of IgSF molecules. In order to demonstrate this, β 2 m from a cartilaginous fish, nurse shark (Ginglymostoma cirratum), was expressed, refolded, purified and crystallized. Diffraction data were collected to a resolution of 2.3 Å. The crystal belonged to space group P3 2 21, with unit-cell parameters a = b = 88.230, c = 67.146 Å. The crystal structure contained two molecules in the asymmetric unit. The results will provide structural information for study of the evolution of β 2 m and IgSF in the AIS

  14. Evasive mating behaviour by female nurse sharks, Ginglymostoma cirratum (Bonnaterre, 1788, in an equatorial insular breeding ground

    Directory of Open Access Journals (Sweden)

    André S. Afonso

    Full Text Available ABSTRACT Mating events and aggregations of vulnerable nurse sharks Ginglymostoma cirratum were recorded in the insular protected area of Fernando de Noronha (FEN, Brazil, between April and August 2015. Female sharks were observed clustering in groups of up to 14 individuals in shallow water adjacent to the shore. Several evasive mating behaviours in the presence of males were noticed, including shoreward movement, positioning ventral side up at the sea surface with emerged pectoral and pelvic fins, body rolling and caudal fin thrashing. Fresh bite marks indicative of male courtship and coupling attempts were visible in female's pectoral and caudal fins. Altogether, the observed behaviours match previous reports of non-cooperative female nurse sharks during mating opportunities. An extended mating season coupled with a persistent use of inshore habitats result in nurse sharks being particularly vulnerable to human pressure during a most sensitive stage of their life cycle. The effective conservation of nurse shark populations from the western South Atlantic may thus depend on the protection of critical habitats where this species aggregates to reproduce. Explicitly addressing environmental requirements by vulnerable species in local management strategies is indispensable to ensure that human pressure, including ecotourism development, does not collide with stipulated conservation aims.

  15. Characterization of arrangement and expression of the beta-2 microglobulin locus in the sandbar and nurse shark.

    Science.gov (United States)

    Chen, Hao; Kshirsagar, Sarika; Jensen, Ingvill; Lau, Kevin; Simonson, Caitlin; Schluter, Samuel F

    2010-02-01

    Beta 2 microglobulin (beta2m) is an essential subunit of major histocompatibility complex (MHC) type I molecules. In this report, beta2m cDNAs were identified and sequenced from sandbar shark spleen cDNA library. Sandbar shark beta2m gene encodes one amino acid less than most teleost beta2m genes, and 3 amino acids less than mammal beta2m genes. Although sandbar shark beta2m protein contains one beta sheet less than that of human in the predicted protein structure, the overall structure of beta2m proteins is conserved during evolution. Germline gene for the beta2m in sandbar and nurse shark is present as a single locus. It contains three exons and two introns. CpG sites are evenly distributed in the shark beta2m loci. Several DNA repeat elements were also identified in the shark beta2m loci. Sequence analysis suggests that the beta2m locus is not linked to the MHC I loci in the shark genome.

  16. Shark hunting - An indiscriminate trade endangering elasmobranchs to extinction

    Digital Repository Service at National Institute of Oceanography (India)

    Verlecar, X.N.; Snigdha; Desai, S.R.; Dhargalkar, V.K.

    - head/round headed shark (Sphyrna zygaena), grey dog shark (R. acutus), sharp-nosed/yellow dog shark (S. lati- caudus) and black-finned/blacktip shark (C. melanop- terus). Most of the shark fin exports have been directed to Hong Kong and Singapore...

  17. Implantable Neural Interfaces for Sharks

    Science.gov (United States)

    2007-05-01

    technology for recording and stimulating from the auditory and olfactory sensory nervous systems of the awake, swimming nurse shark , G. cirratum (Figures...overlay of the central nervous system of the nurse shark on a horizontal MR image. Implantable Neural Interfaces for Sharks ...Neural Interfaces for Characterizing Population Responses to Odorants and Electrical Stimuli in the Nurse Shark , Ginglymostoma cirratum.” AChemS Abs

  18. Functional morphology of the feeding apparatus, feeding constraints, and suction performance in the nurse shark Ginglymostoma cirratum.

    Science.gov (United States)

    Motta, Philip J; Hueter, Robert E; Tricas, Timothy C; Summers, Adam P; Huber, Daniel R; Lowry, Dayv; Mara, Kyle R; Matott, Michael P; Whitenack, Lisa B; Wintzer, Alpa P

    2008-09-01

    The nurse shark, Ginglymostoma cirratum, is an obligate suction feeder that preys on benthic invertebrates and fish. Its cranial morphology exhibits a suite of structural and functional modifications that facilitate this mode of prey capture. During suction-feeding, subambient pressure is generated by the ventral expansion of the hyoid apparatus and the floor of its buccopharyngeal cavity. As in suction-feeding bony fishes, the nurse shark exhibits expansive, compressive, and recovery kinematic phases that produce posterior-directed water flow through the buccopharyngeal cavity. However, there is generally neither a preparatory phase nor cranial elevation. Suction is generated by the rapid depression of the buccopharyngeal floor by the coracoarcualis, coracohyoideus, and coracobranchiales muscles. Because the hyoid arch of G. cirratum is loosely connected to the mandible, contraction of the rectus cervicis muscle group can greatly depress the floor of the buccopharyngeal cavity below the depressed mandible, resulting in large volumetric expansion. Suction pressures in the nurse shark vary greatly, but include the greatest subambient pressures reported for an aquatic-feeding vertebrate. Maximum suction pressure does not appear to be related to shark size, but is correlated with the rate of buccopharyngeal expansion. As in suction-feeding bony fishes, suction in the nurse shark is only effective within approximately 3 cm in front of the mouth. The foraging behavior of this shark is most likely constrained to ambushing or stalking due to the exponential decay of effective suction in front of the mouth. Prey capture may be facilitated by foraging within reef confines and close to the substrate, which can enhance the effective suction distance, or by foraging at night when it can more closely approach prey.

  19. A stochastic locomotor control model for the nurse shark, Ginglymostoma cirratum.

    Science.gov (United States)

    Gerald, K B; Matis, J H; Kleerekoper, H

    1978-06-12

    The locomotor behavior of the nurse shark (Ginglymostoma cirratum) is characterized by 17 variables (frequency and ratios of left, right, and total turns; their radians; straight paths (steps); distance travelled; and velocity) Within each of these variables there is an internal time dependency the structure of which was elaborated together with an improved statistical model predicting their behavior within 90% confidence limits. The model allows for the sensitive detection of subtle locomotor response to sensory stimulation as values of variables may exceed the established confidence limits within minutes after onset of the stimulus. The locomotor activity is well described by an autoregression time series model and can be predicted by only seven variables. Six of these form two independently operating clusters. The first one consists of: the number of right turns, the distance travelled and the mean velocity; the second one of: the mean size of right turns, of left turns, and of all turns. The same clustering is obtained independently by a cluster analysis of cross-sections of the seven time series. It is apparent that, among a total of 17 locomotor variables, seven behave as individually independent agents, presumably controlled by seven separate and independent centers. The output of each center can only be predicted by its own behavior. In spite of the individual of the seven variables, their internal structure is similar in important aspects which may result from control by a common command center. The shark locomotor model differs in important aspects from the previously constructed for the goldfish. The interdependence of the locomotor variables in both species may be related to the control mechanisms postulated by von Holst for the coordination of rhythmic fin movements in fishes. A locomotor control model for the nurse shark is proposed.

  20. Two visual pathways to the telencephalon in the nurse shark (Ginglymostoma cirratum). I. Retinal projections.

    Science.gov (United States)

    Luiten, P G

    1981-03-10

    The central projections of the retina in the nurse shark were studied by anterograde transport of horseradish peroxidase and tritiated proline. With regard to efferent retinal fibers, both techniques gave completely identical results. Projections were found to pretectal area, dorsal thalamus, basal optic nucleus, and optic tectum, all at the contralateral side. The retinal target cells in the dorsal thalamus are restricted to the ventrolateral optic nucleus and the posterior optic nucleus. No evidence was found for an earlier-reported projection to the lateral geniculate nucleus. The present findings show that the ventrolateral optic nucleus exhibits homological features of the dorsal lateral geniculate nucleus in other vertebrate groups, whereas the lateral geniculate nucleus of the nurse shark is much more comparable to the nucleus rotundus of teleosts and birds and would be more appropriately so named. The application of the HRP technique also allowed us to study afferents to the retina by retrograde transport of tracer. Retrogradely labeled cells were observed in the contralateral optic tectum and are apparently similar to those reported for teleosts and birds.

  1. Isolation and characterization of major histocompatibility complex class IIB genes from the nurse shark.

    Science.gov (United States)

    Bartl, S; Weissman, I L

    1994-01-04

    The major histocompatibility complex (MHC) contains a set of linked genes which encode cell surface proteins involved in the binding of small peptide antigens for their subsequent recognition by T lymphocytes. MHC proteins share structural features and the presence and location of polymorphic residues which play a role in the binding of antigens. In order to compare the structure of these molecules and gain insights into their evolution, we have isolated two MHC class IIB genes from the nurse shark, Ginglymostoma cirratum. Two clones, most probably alleles, encode proteins which differ by 13 amino acids located in the putative antigen-binding cleft. The protein structure and the location of polymorphic residues are similar to their mammalian counterparts. Although these genes appear to encode a typical MHC protein, no T-cell-mediated responses have been demonstrated in cartilaginous fish. The nurse shark represents the most phylogenetically primitive organism in which both class IIA [Kasahara, M., Vazquez, M., Sato, K., McKinney, E.C. & Flajnik, M.F. (1992) Proc. Natl. Acad. Sci USA 89, 6688-6692] and class IIB genes, presumably encoding the alpha/beta heterodimer, have been isolated.

  2. Diversity and repertoire of IgW and IgM VH families in the newborn nurse shark.

    Science.gov (United States)

    Rumfelt, Lynn L; Lohr, Rebecca L; Dooley, Helen; Flajnik, Martin F

    2004-05-06

    Adult cartilaginous fish express three immunoglobulin (Ig) isotypes, IgM, IgNAR and IgW. Newborn nurse sharks, Ginglymostoma cirratum, produce 19S (multimeric) IgM and monomeric/dimeric IgM1gj, a germline-joined, IgM-related VH, and very low amounts of 7S (monomeric) IgM and IgNAR proteins. Newborn IgNAR VH mRNAs are diverse in the complementarity-determining region 3 (CDR3) with non-templated nucleotide (N-region) addition, which suggests that, unlike in many other vertebrates, terminal deoxynucleotidyl transferase (TdT) expressed at birth is functional. IgW is present in the lungfish, a bony fish sharing a common ancestor with sharks 460 million years ago, implying that the IgW VH family is as old as the IgM VH family. This nurse shark study examined the IgM and IgW VH repertoire from birth through adult life, and analyzed the phylogenetic relationships of these gene families. IgM and IgW VH cDNA clones isolated from newborn nurse shark primary and secondary lymphoid tissues had highly diverse and unique CDR3 with N-region addition and VDJ gene rearrangement, implicating functional TdT and RAG gene activity. Despite the clear presence of N-region additions, newborn CDR3 were significantly shorter than those of adults. The IgM clones are all included in a conventional VH family that can be classified into five discrete groups, none of which is orthologous to IgM VH genes in other elasmobranchs. In addition, a novel divergent VH family was orthologous to a published monotypic VH horn shark family. IgW VH genes have diverged sufficiently to form three families. IgM and IgW VH serine codons using the potential somatic hypermutation hotspot sequence occur mainly in VH framework 1 (FR1) and CDR1. Phylogenetic analysis of cartilaginous fish and lungfish IgM and IgW demonstrated they form two major ancient gene groups; furthermore, these VH genes generally diversify (duplicate and diverge) within a species. As in ratfish, sandbar and horn sharks, most nurse shark IgM VH

  3. Diversity and repertoire of IgW and IgM VH families in the newborn nurse shark

    Directory of Open Access Journals (Sweden)

    Dooley Helen

    2004-05-01

    Full Text Available Abstract Background Adult cartilaginous fish express three immunoglobulin (Ig isotypes, IgM, IgNAR and IgW. Newborn nurse sharks, Ginglymostoma cirratum, produce 19S (multimeric IgM and monomeric/dimeric IgM1gj, a germline-joined, IgM-related VH, and very low amounts of 7S (monomeric IgM and IgNAR proteins. Newborn IgNAR VH mRNAs are diverse in the complementarity-determining region 3 (CDR3 with non-templated nucleotide (N-region addition, which suggests that, unlike in many other vertebrates, terminal deoxynucleotidyl transferase (TdT expressed at birth is functional. IgW is present in the lungfish, a bony fish sharing a common ancestor with sharks 460 million years ago, implying that the IgW VH family is as old as the IgM VH family. This nurse shark study examined the IgM and IgW VH repertoire from birth through adult life, and analyzed the phylogenetic relationships of these gene families. Results IgM and IgW VH cDNA clones isolated from newborn nurse shark primary and secondary lymphoid tissues had highly diverse and unique CDR3 with N-region addition and VDJ gene rearrangement, implicating functional TdT and RAG gene activity. Despite the clear presence of N-region additions, newborn CDR3 were significantly shorter than those of adults. The IgM clones are all included in a conventional VH family that can be classified into five discrete groups, none of which is orthologous to IgM VH genes in other elasmobranchs. In addition, a novel divergent VH family was orthologous to a published monotypic VH horn shark family. IgW VH genes have diverged sufficiently to form three families. IgM and IgW VH serine codons using the potential somatic hypermutation hotspot sequence occur mainly in VH framework 1 (FR1 and CDR1. Phylogenetic analysis of cartilaginous fish and lungfish IgM and IgW demonstrated they form two major ancient gene groups; furthermore, these VH genes generally diversify (duplicate and diverge within a species. Conclusion As in ratfish

  4. Expression, purification, crystallization and preliminary X-ray diffraction analysis of nurse shark β2-microglobulin.

    Science.gov (United States)

    Lu, Shuangshuang; Yao, Shugang; Chen, Rong; Zhang, Nianzhi; Chen, Jianmin; Gao, Feng; Xia, Chun

    2012-04-01

    β(2)-Microglobulin (β(2)m) is an essential subunit of the major histocompatibility complex (MHC) class I molecule that helps to stabilize the structure of peptide-MHC I (pMHC I). It is also one of the typical immunoglobulin superfamily (IgSF) molecules in the adaptive immune system (AIS). Sharks belong to the cartilaginous fish, which are the oldest jawed vertebrate ancestors with an AIS to exist in the world. Thus, the study of cartilaginous fish β(2)m would help in understanding the evolution of IgSF molecules. In order to demonstrate this, β(2)m from a cartilaginous fish, nurse shark (Ginglymostoma cirratum), was expressed, refolded, purified and crystallized. Diffraction data were collected to a resolution of 2.3 Å. The crystal belonged to space group P3(2)21, with unit-cell parameters a = b = 88.230, c = 67.146 Å. The crystal structure contained two molecules in the asymmetric unit. The results will provide structural information for study of the evolution of β(2)m and IgSF in the AIS. © 2012 International Union of Crystallography. All rights reserved.

  5. Non-coordinate expression of J-chain and Blimp-1 define nurse shark plasma cell populations during ontogeny

    Science.gov (United States)

    Castro, Caitlin D.; Ohta, Yuko; Dooley, Helen; Flajnik, Martin F.

    2014-01-01

    Summary Blimp-1 is the master regulator of plasma cell development, controlling genes such as J-chain and secretory Ig heavy chain. However, some mammalian plasma cells do not express J-chain, and mammalian B1 cells secrete “natural” IgM antibodies without upregulating Blimp-1. While these results have been controversial in mammalian systems, here we describe subsets of normally occurring Blimp-1- antibody secreting cells in nurse sharks, found in lymphoid tissues at all ontogenic stages. Sharks naturally produce large amounts of both pentameric (classically ‘19S’) and monomeric (classically ‘7S’) IgM, the latter an indicator of adaptive immunity. Consistent with the mammalian paradigm, shark Blimp-1 is expressed in splenic 7S IgM-secreting cells, though rarely detected in the J-chain+ cells producing 19S IgM. Although IgM transcript levels are lower in J-chain+ cells, these cells nevertheless secrete 19S IgM in the absence of Blimp-1, as demonstrated by ELISPOT and metabolic labeling. Additionally, cells in the shark bone marrow equivalent (epigonal) are Blimp-1-. Our data suggest that, in sharks, 19S-secreting cells and other secreting memory B cells in the epigonal can be maintained for long periods without Blimp-1, but like in mammals, Blimp-1 is required for terminating the B cell program following an adaptive immune response in the spleen. PMID:23897025

  6. Mitochondrial genome and phylogenetic position of the tawny nurse shark (Nebrius ferrugineus).

    Science.gov (United States)

    Wang, Junjie; Chen, Hao; Lin, Lingling; Ai, Weiming; Chen, Xiao

    2017-01-01

    The complete mitochondrial genome of the tawny nurse shark (Nebrius ferrugineus) was first presented in this study. It was 16 693 bp in length with the typical gene order in vertebrates. The overall base composition was 33.6% A, 25.6% C, 12.7% G and 28.1% T. Two start (ATG and GTG) and two stop (TAG and TAA/T--) codons were found in the protein-coding genes. The size of 22 tRNA genes ranged from 67 to 75 bp. The origin of L-strand replication could form a hairpin structure. All nodes strongly supported that N. ferrugineus was placed as sister to Rhincodon typus in the Bayesian tree.

  7. Isolation and initial characterisation of complement components C3 and C4 of the nurse shark and the channel catfish.

    Science.gov (United States)

    Dodds, A W; Smith, S L; Levine, R P; Willis, A C

    1998-01-01

    Complement components C3 and C4 have been isolated from the serum of the nurse shark (Ginglymostoma cirratum) and of the channel catfish (Ictalurus punctatus). As in the higher vertebrates, the fish C4 proteins have three-chain structures while the C3 proteins have two-chain structures. All four proteins have intra-chain thioesters located within their highest molecular mass polypeptides. N-terminal sequence analysis of the polypeptides has confirmed the identity of the proteins. In all cases except the catfish C3 alpha-chain, which appears to have a blocked N-terminus, sequence similarities are apparent in comparisons with the chains of C3 and C4 from higher vertebrates. We have confirmed that the activity/protein previously designated C2n is the nurse shark analogue of mammalian C4. This is the first report of structural evidence for C4 in both the bony and cartilaginous fish.

  8. A specific inactivator of mammalian C'4 isolated from nurse shark (Ginglymostoma cirratum) serum.

    Science.gov (United States)

    Jensen, J A

    1969-08-01

    A material which specifically inactivates mammalian C'4 was isolated from low ionic strength precipitates of nurse shark serum. The C'4 inactivator was not detected in whole serum. The conditions of its generation and its immunoelectrophoretic behavior seem to indicate that it is an enzymatically formed cleavage product of a precursor contained in whole shark serum. The inactivator was partially purified and characterized. It had an S-value of 3.3 (sucrose gradient) which was in agreement with its retardation on gel filtration, was stable between pH 5.0 and 10.0, had a half-life of 5 min at 56 degrees C, pH 7.5, was inactivated by trypsin and was nontoxic. Its powerful anticomplementary activity in vitro and in vivo was solely due to the rapid inactivation of C'4; no other complement components were affected. No cofactor requirement was observed for the equally rapid inactivation of highly purified human and guinea pig C'4. The kinetics of C'4 inactivation and TAME hydrolysis, the greater anodic mobility of inactivated human C'4, and the influence of temperature on the rate of inactivation suggest that the inactivator is an enzyme and C'4 its substrate. This conclusion was supported by the more recent detection of a split product of C'4. Intravenous administration of the C'4 inactivator could prevent lethal Forssman shock and suppress the Arthus reaction in guinea pigs; it prolonged significantly the rejection time of renal xenografts but had no detectable effect on passive cutaneous anaphylaxis. Anaphylatoxin could be generated in C'4 depleted guinea pig serum with the cobra venom factor, but not with immune precipitates. The possible relationship between C'1 esterase and the C'4 inactivator is discussed on the basis of similarities and dissimilarities.

  9. Noncoordinate expression of J-chain and Blimp-1 define nurse shark plasma cell populations during ontogeny.

    Science.gov (United States)

    Castro, Caitlin D; Ohta, Yuko; Dooley, Helen; Flajnik, Martin F

    2013-11-01

    B-lymphocyte-induced maturation protein 1 (Blimp-1) is the master regulator of plasma cell development, controlling genes such as those encoding J-chain and secretory Ig heavy chain. However, some mammalian plasma cells do not express J-chain, and mammalian B1 cells secrete "natural" IgM antibodies without upregulating Blimp-1. While these results have been controversial in mammalian systems, here we describe subsets of normally occurring Blimp-1(-) antibody-secreting cells in nurse sharks, found in lymphoid tissues at all ontogenic stages. Sharks naturally produce large amounts of both pentameric (classically "19S") and monomeric (classically "7S") IgM, the latter an indicator of adaptive immunity. Consistent with the mammalian paradigm, shark Blimp-1 is expressed in splenic 7S IgM-secreting cells, though rarely detected in the J-chain(+) cells producing 19S IgM. Although IgM transcript levels are lower in J-chain(+) cells, these cells nevertheless secrete 19S IgM in the absence of Blimp-1, as demonstrated by ELISPOT and metabolic labeling. Additionally, cells in the shark BM equivalent (epigonal) are Blimp-1(-). Our data suggest that, in sharks, 19S-secreting cells and other secreting memory B cells in the epigonal are maintained for long periods without Blimp-1, but like in mammals, Blimp-1 is required for terminating the B-cell program following an adaptive immune response in the spleen. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Nitric oxide production by nurse shark (Ginglymostoma cirratum) and clearnose skate (Raja eglanteria) peripheral blood leucocytes.

    Science.gov (United States)

    Walsh, Cathy J; Toranto, Jason D; Gilliland, C Taylor; Noyes, David R; Bodine, Ashby B; Luer, Carl A

    2006-01-01

    Reactive nitrogen intermediates, such as nitric oxide (NO), are important immunomodulators in vertebrate immune systems, but have yet to be identified as mediators of host defence in any member of class Chondrichthyes, the cartilaginous fishes. In the present study, production of NO by nurse shark (Ginglymostoma cirratum) peripheral blood leucocytes (PBL) stimulated with bacterial cell wall lipopolysaccharide (LPS) was investigated. PBL were cultured for 24 to 96 h following stimulation with LPS at concentrations ranging from 0 to 25 microg ml(-1), in both serum-supplemented and serum-free culture conditions. Production of NO was measured indirectly using the Griess reaction, with maximal NO production occurring after 72 h using 10% FBS and 10 microg LPS ml(-1). Application of these culture conditions to PBL from another cartilaginous fish (clearnose skate, Raja eglanteria) resulted in a similar NO response. Addition of a specific inhibitor of inducible nitric oxide synthase (iNOS), L-N(6)-(1-iminoethyl)lysine (L-NIL), resulted in a significant decrease in the production of NO by PBL from both species.

  11. Molecular cloning, structural analysis and expression of complement component Bf/C2 genes in the nurse shark, Ginglymostoma cirratum.

    Science.gov (United States)

    Shin, Dong-Ho; Webb, Barbara; Nakao, Miki; Smith, Sylvia L

    2007-01-01

    Factor B and C2 are serine proteases that provide the catalytic subunits of C3 and C5 convertases of the alternative (AP) and classical (CP) complement pathways. Two Bf/C2 cDNAs, GcBf/C2-1 and -2 (previously referred to as nsBf/C2-A and nsBf/C2-B), were isolated from the nurse shark, Ginglymostoma cirratum. GcBf/C2-1 and -2 are 3364 and 3082bp in length and encode a leader peptide, three CCPs, one VWFA, the serine protease domain and have a putative factor D/C1s/MASP cleavage site. Southern blots show that there might be up to two Bf/C2-like genes for each of the two GcBf/C2 isoforms. GcBf/C2-1 and -2 are constitutively expressed, albeit at different levels, in all nine tissues examined. Expression in erythrocytes is a novel finding. Structural analysis has revealed that the localization of glycosylation sites in the SP domain of both putative proteins indicates that the molecular organization of the shark molecules is more like C2 than factor B. Phylogenetic analysis indicates that GcBf/C2-1 and -2 and TrscBf of Triakis scyllia (another shark species) originated from a common ancestor and share a remote ancestor with Bf and C2 of mammals and bony fish.

  12. Anatomy of the feeding apparatus of the nurse shark, Ginglymostoma cirratum.

    Science.gov (United States)

    Motta; Wilga

    1999-07-01

    The anatomy of the feeding apparatus of the nurse shark, Ginglymostoma cirratum, was investigated by gross dissection and computer axial tomography. The labial cartilages, jaws, jaw suspension, muscles, and ligaments of the head are described. Palatoquadrate cartilages articulate with the chondrocranium caudally by short, laterally projecting hyomandibulae and rostrally by ethmoorbital articulations. Short orbital processes of the palatoquadrates are joined to the ethmoid region of the chondrocranium by short, thin ethmopalatine ligaments. In addition, various ligaments, muscles, and the integument contribute to the suspension of the jaws. When the mouth is closed and the palatoquadrate retracted, the palatine process of the palatoquadrate is braced against the ventral surface of the nasal capsule and the ascending process of the palatoquadrate is in contact with the rostrodorsal end of the suborbital shelf. When the mandible is depressed and the palatoquadrate protrudes slightly rostroventrally, the palatoquadrate moves away from the chondrocranium. A dual articulation of the quadratomandibular joint restricts lateral movement between the mandible and the palatoquadrate. The vertically oriented preorbitalis muscle spans the gape and is hypothesized to contribute to the generation of powerful crushing forces for its hard prey. The attachment of the preorbitalis to the prominent labial cartilages is also hypothesized to assist in the retraction of the labial cartilages during jaw closure. Separate levator palatoquadrati and spiracularis muscles, which are longitudinally oriented and attach the chondrocranium to the palatoquadrate, are hypothesized to assist in the retraction of the palatoquadrate during the recovery phase of feeding kinematics. Morphological specializations for suction feeding that contribute to large subambient suction pressures include hypertrophied coracohyoideus and coracobranchiales muscles to depress the hyoid and branchial arches, a small

  13. In vitro metabolism of the pro-carcinogen aflatoxin B1 by liver preparations of the calf, nurse shark and clearnose skate.

    Science.gov (United States)

    Bodine, A B; Luer, C A; Gangjee, S A; Walsh, C J

    1989-01-01

    1. Liver postmitochondrial supernatant preparations of calf, clearnose skate, and nurse shark were able to metabolize the fungal toxin aflatoxin B1 to various metabolites. 2. Calf liver produced aflatoxin M1 and Q1 as the major chloroform soluble metabolites, with small amounts of aflatoxicol formed during incubation. 3. Liver preparations of the elasmobranchs, however, produced aflatoxicol as the major chloroform soluble metabolite with no other metabolite being detected. 4. The water soluble metabolite profiles for the three species were also quite different with the tris diol adduct being produced to a much greater extent in calf liver preparations. 5. Aflatoxicol production by the elasmobranch liver homogenates was reversible with the skate reconverting a large amount (30%) of aflatoxicol to AFB1. The nurse shark, however, appeared to convert a portion of aflatoxicol to an unknown metabolite more polar than AFB1. 6. Calf liver DNA bound approximately 3 x more 3H-AFB1 than shark liver DNA.

  14. Shark Cartilage

    Science.gov (United States)

    Shark cartilage (tough elastic tissue that provides support, much as bone does) used for medicine comes primarily from sharks ... Several types of extracts are made from shark cartilage including squalamine lactate, AE-941, and U-995. ...

  15. Somatic hypermutation of T cell receptor α chain contributes to selection in nurse shark thymus.

    Science.gov (United States)

    Ott, Jeannine A; Castro, Caitlin D; Deiss, Thaddeus C; Ohta, Yuko; Flajnik, Martin F; Criscitiello, Michael F

    2018-04-17

    Since the discovery of the T cell receptor (TcR), immunologists have assigned somatic hypermutation (SHM) as a mechanism employed solely by B cells to diversify their antigen receptors. Remarkably, we found SHM acting in the thymus on α chain locus of shark TcR. SHM in developing shark T cells likely is catalyzed by activation-induced cytidine deaminase (AID) and results in both point and tandem mutations that accumulate non-conservative amino acid replacements within complementarity-determining regions (CDRs). Mutation frequency at TcRα was as high as that seen at B cell receptor loci (BcR) in sharks and mammals, and the mechanism of SHM shares unique characteristics first detected at shark BcR loci. Additionally, fluorescence in situ hybridization showed the strongest AID expression in thymic corticomedullary junction and medulla. We suggest that TcRα utilizes SHM to broaden diversification of the primary αβ T cell repertoire in sharks, the first reported use in vertebrates. © 2018, Ott et al.

  16. Five new species of Pedibothrium (Tetraphyllidea: Onchobothriidae) from the tawny nurse shark, Nebrius ferrugineus, in the Pacific Ocean.

    Science.gov (United States)

    Caira, J N; Tracy, Randall; Euzet, L

    2004-04-01

    The spiral intestines of 7 Tawny nurse sharks (Nebrius ferrugineus; Rhincodontidae) from Australia and French Polynesia were examined for tapeworms. These sharks hosted 5 new species of Pedibothrium. The 5 species were prepared for light and scanning electron microscopy. Whereas 3 of the species exhibit the bipronged hooks typical of members of Pedibothrium, 1 species was found to possess tiny unipronged hooks or to lack some, or all, hooks, and all individuals of the fifth species appeared to lack bothridial hooks entirely. Nonetheless, the otherwise remarkable similarities between these species and the species of Pedibothrium bearing bipronged hooks were considered to be sufficient to justify the placement of these 2 species in this genus. All 5 species possess proglottid features typical of Pedibothrium, including a uterus that extends anteriorly only to the level of the cirrus sac and a cirrus sac that is bent anteriorly and is crossed by the vagina. All 5 species also exhibit uniloculated bothridia. Of particular note was the fact that all 5 species exhibit bladelike spinitrichs with elongated distal tips, a form of microthrix currently known only from species of Pedibothrium. As a consequence, these species were treated as possessing modified hooks or as having lost hooks. The diagnoses of Pedibothrium and Onchobothriidae were emended to include these species. Each of the 5 new species bears a strong resemblance to 1 or more species of Pedibothrium hosted by a species of rhincodontid shark other than N. ferrugineus. Much of Southwell's type and voucher material of Pedibothrium was located and used to verify the identity of Pedibothrium kerkhami and many of the hosts from which Southwell's material of Pedibothrium was collected. This material suggests that P. kerkhami parasitizes Stegostoma fasciatum and not N. ferrugineus.

  17. Structural analysis of the nurse shark (new) antigen receptor (NAR): molecular convergence of NAR and unusual mammalian immunoglobulins.

    Science.gov (United States)

    Roux, K H; Greenberg, A S; Greene, L; Strelets, L; Avila, D; McKinney, E C; Flajnik, M F

    1998-09-29

    We recently have identified an antigen receptor in sharks called NAR (new or nurse shark antigen receptor) that is secreted by splenocytes but does not associate with Ig light (L) chains. The NAR variable (V) region undergoes high levels of somatic mutation and is equally divergent from both Ig and T cell receptors (TCR). Here we show by electron microscopy that NAR V regions, unlike those of conventional Ig and TCR, do not form dimers but rather are independent, flexible domains. This unusual feature is analogous to bona fide camelid IgG in which modifications of Ig heavy chain V (VH) sequences prevent dimer formation with L chains. NAR also displays a uniquely flexible constant (C) region. Sequence analysis and modeling show that there are only two types of expressed NAR genes, each having different combinations of noncanonical cysteine (Cys) residues in the V domains that likely form disulfide bonds to stabilize the single antigen-recognition unit. In one NAR class, rearrangement events result in mature genes encoding an even number of Cys (two or four) in complementarity-determining region 3 (CDR3), which is analogous to Cys codon expression in an unusual human diversity (D) segment family. The NAR CDR3 Cys generally are encoded by preferred reading frames of rearranging D segments, providing a clear design for use of preferred reading frame in antigen receptor D regions. These unusual characteristics shared by NAR and unconventional mammalian Ig are most likely the result of convergent evolution at the molecular level.

  18. Quantitative anatomical and behavioral analyses of regeneration and collateral sprouting following spinal cord transection in the nurse shark (ginglymostoma cirratum).

    Science.gov (United States)

    Gelderd, J B

    1979-01-01

    The spinal cord was transected at the mid-thoracic level in 32 nurse sharks. Four animals per group were sacrificed at intervals of 10, 20, 30, 40, 60 and 90 days postoperative. Two groups of fish underwent a subsequent spinla1 cord retransection at the same site at 90 days and were sacrificed 10 and 20 days later. Three sections of spinal cord were removed from each shark for histological analysis. Behaviorally, timed trials for swimming speed and a strength test for axial musculature contraction caudal to the lesion site were performed at 5 day postoperative intervals. Histological analysis showed little regeneration (9-13 percent) of two descending tracts 90 days following the lesion and no return of rostrally controlled movements caudal to the lesion. However, synaptic readjustment did occur caudal to the lesion. This phenomenon was attributed to local segmental sprouting of adjacent, intact nerve fibers. A close correlation was shown between this synaptic readjustment and the strength of uncontrollable undulatory movements seen caudal to the lesion site following spinal cord transection. The relationship of regeneration and collateral sprouting to quantitative behavioral changes is discussed.

  19. Shark complement: an assessment.

    Science.gov (United States)

    Smith, S L

    1998-12-01

    The classical (CCP) and alternative (ACP) pathways of complement activation have been established for the nurse shark (Ginglymostoma cirratum). The isolation of a cDNA clone encoding a mannan-binding protein-associated serine protease (MASP)-1-like protein from the Japanese dogfish (Triakis scyllia) suggests the presence of a lectin pathway. The CCP consists of six functionally distinct components: C1n, C2n, C3n, C4n, C8n and C9n, and is activated by immune complexes in the presence of Ca++ and Mg++ ions. The ACP is antibody independent, requiring Mg++ ions and a heat-labile 90 kDa factor B-like protein for activity. Proteins considered homologues of C1q, C3 and C4 (C2n) of the mammalian complement system have been isolated from nurse shark serum. Shark C1q is composed of at least two chain types each showing 50% identity to human C1q chains A and B. Partial sequence of the globular domain of one of the chains shows it to be C1q-like rather than like mannan-binding protein. N-terminal amino acid sequences of the alpha and beta chain of shark C3 and C4 molecules show significant identity with corresponding human C3 and C4 chains. A sequence representing shark C4 gamma chain, shows little similarity to human C4 gamma chain. The terminal shark components C8n and C9n are functional analogues of mammalian C8 and C9. Anaphylatoxin activity has been demonstrated in activated shark serum, and porcine C5a desArg induces shark leucocyte chemotaxis. The deduced amino acid sequence of a partial C3 cDNA clone from the nurse shark shows 50%, 30% and 24% homology with the corresponding region of mammalian C3, C4 and alpha 2-macroglobulin. Deduced amino acid sequence data from partial Bf/C2 cDNA clones, two from the nurse shark and one from the Japanese dogfish, suggest that at least one species of elasmobranch has two distinct Bf/C2 genes.

  20. Evolutionarily Conserved TCR Binding Sites, Identification of T Cells in Primary Lymphoid Tissues, and Surprising Trans-Rearrangements in Nurse Shark

    OpenAIRE

    Criscitiello, Michael F.; Ohta, Yuko; Saltis, Mark; McKinney, E. Churchill; Flajnik, Martin F.

    2010-01-01

    Cartilaginous fish are the oldest animals that generate RAG-based Ag receptor diversity. We have analyzed the genes and expressed transcripts of the four TCR chains for the first time in a cartilaginous fish, the nurse shark (Ginglymostoma cirratum). Northern blotting found TCR mRNA expression predominantly in lymphoid and mucosal tissues. Southern blotting suggested translocon-type loci encoding all four chains. Based on diversity of V and J segments, the expressed combinatorial diversity fo...

  1. Evolutionarily conserved TCR binding sites, identification of T cells in primary lymphoid tissues, and surprising trans-rearrangements in nurse shark.

    Science.gov (United States)

    Criscitiello, Michael F; Ohta, Yuko; Saltis, Mark; McKinney, E Churchill; Flajnik, Martin F

    2010-06-15

    Cartilaginous fish are the oldest animals that generate RAG-based Ag receptor diversity. We have analyzed the genes and expressed transcripts of the four TCR chains for the first time in a cartilaginous fish, the nurse shark (Ginglymostoma cirratum). Northern blotting found TCR mRNA expression predominantly in lymphoid and mucosal tissues. Southern blotting suggested translocon-type loci encoding all four chains. Based on diversity of V and J segments, the expressed combinatorial diversity for gamma is similar to that of human, alpha and beta may be slightly lower, and delta diversity is the highest of any organism studied to date. Nurse shark TCRdelta have long CDR3 loops compared with the other three chains, creating binding site topologies comparable to those of mammalian TCR in basic paratope structure; additionally, nurse shark TCRdelta CDR3 are more similar to IgH CDR3 in length and heterogeneity than to other TCR chains. Most interestingly, several cDNAs were isolated that contained IgM or IgW V segments rearranged to other gene segments of TCRdelta and alpha. Finally, in situ hybridization experiments demonstrate a conservation of both alpha/beta and gamma/delta T cell localization in the thymus across 450 million years of vertebrate evolution, with gamma/delta TCR expression especially high in the subcapsular region. Collectively, these data make the first cellular identification of TCR-expressing lymphocytes in a cartilaginous fish.

  2. The 'greying' of the United Kingdom nursing workforce: implications for employment policy and practice.

    Science.gov (United States)

    Buchan, J

    1999-10-01

    One in five nurses on the United Kingdom (UK) professional register is aged 50 years or older. Over the next few years, the profession will lose, through retirement, many of its most experienced practitioners. The significance for policy makers and for employers of this age-shift is two-fold. Firstly it is clear that greater numbers of nurses and midwives are reaching, or soon will reach, potential retirement age. Secondly many more nurses are now reaching their middle years and they are likely to have different requirements and attitudes to nursing work. This paper examines the employment policy and practice of the ageing of the UK nursing population. The paper examines data from official sources, and information from attitudinal surveys and case studies with employing organizations to assess the major effects of the ageing of the nursing workforce. Key findings are that the age profile of those nurses working in the National Health Service appears to be 'younger' than that of the total population, with the age profile of nurses working in nursing homes and as practice nurses being older than that of the NHS nursing workforce. However, the overall age profile of NHS nurses masks considerable variation between specialties and trusts, and the 'pool' of potential nurse returners from which the NHS and other employers attempts to recruit, is declining in numbers, as it too ages. Other major issues requiring policy attention are the provision of appropriate flexible hours to older nurses who have caring responsibilities, improving access to continuing professional development, and reducing pension provision inflexibility.

  3. Sharks senses and shark repellents.

    Science.gov (United States)

    Hart, Nathan S; Collin, Shaun P

    2015-01-01

    Despite over 70 years of research on shark repellents, few practical and reliable solutions to prevent shark attacks on humans or reduce shark bycatch and depredation in commercial fisheries have been developed. In large part, this deficiency stems from a lack of fundamental knowledge of the sensory cues that drive predatory behavior in sharks. However, the widespread use of shark repellents is also hampered by the physical constraints and technical or logistical difficulties of deploying substances or devices in an open-water marine environment to prevent an unpredictable interaction with a complex animal. Here, we summarize the key attributes of the various sensory systems of sharks and highlight residual knowledge gaps that are relevant to the development of effective shark repellents. We also review the most recent advances in shark repellent technology within the broader historical context of research on shark repellents and shark sensory systems. We conclude with suggestions for future research that may enhance the efficacy of shark repellent devices, in particular, the continued need for basic research on shark sensory biology and the use of a multi-sensory approach when developing or deploying shark repellent technology. © 2014 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

  4. Isolation and characterization of a c-type lysozyme from the nurse shark.

    Science.gov (United States)

    Hinds Vaughan, Nichole; Smith, Sylvia L

    2013-12-01

    Lysozyme is a ubiquitous antibacterial enzyme that occurs in numerous invertebrate and vertebrate species. Three forms have been described c-type, g-type and i-type which differ in primary structure. Shark lysozyme has not been characterized; here we report on the isolation and characterization of lysozyme from unstimulated shark (Ginglymostoma cirratum) leukocytes and provide amino acid sequence data across the highly conserved active site of the molecule identifying it to be a c-type lysozyme. A leukocyte lysate was applied either (a) to the first of two sequential DE-52 cellulose columns or alternatively, (b) to a DEAE-Sepharose column. Lysozyme activity in lysate and active fractions was identified by zones of lysis of Micrococcus lysodeikticus cell walls on lysoplates and zones of growth inhibition in agar diffusion assays using Planococcus citreus as the target organism. SDS-PAGE analysis revealed a 14 kDa protein which was identified as lysozyme by mass spectroscopic analysis of peptides, reactivity against anti-HEWL antibodies on a Western blot, hydrolysis of M. lysodeikticus cell walls, and inhibition of growth of P. citreus on AU-gel blots in which the area of growth inhibition correlated to a 14 kDa protein. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Developing Abilities to Navigate Through the Grey Zones in Complex Environments: Nurses' Reasons for Applying to a Clinical Ethics Residency for Nurses.

    Science.gov (United States)

    Jurchak, Martha; Grace, Pamela J; Lee, Susan M; Willis, Danny G; Zollfrank, Angelika A; Robinson, Ellen M

    2017-07-01

    Nurses face complex ethical issues in practice and have to determine appropriate actions. An inability to conceptualize or follow a preferred course of action can give rise to moral uncertainty or moral distress. Both moral uncertainty and moral distress are problematic for nurses and their patients. A program designed to increase nurse confidence in moral decision making, the clinical ethics residency for nurses (CERN), was offered selectively to nurses affiliated with two academic medical centers. This is a report of the analysis of their application essays. Over a 3-year period, 67 application essays were analyzed using conventional content analysis. Applicants comprised one third advanced practice nurses (APNs) and two thirds staff nurses. They were asked to describe their reasons for interest in the CERN and how they would apply the knowledge gained. For conventional content analyses, no theoretical presumptions are used; rather, codes are identified from the data in an iterative manner and eventually collapsed into themes. Initially, broad themes were identified by the CERN team. Subsequently, in-depth and recursive readings were completed by a subset of three members, resulting in refinement of themes and subthemes. The overarching theme identified was "developing abilities to navigate through the 'grey zones' in complex environments." Three subthemes were: (a) nurses encountering patients who are chronically critically ill, culturally diverse, and presenting with complex circumstances; (b) nurses desiring enhanced ethics knowledge and skills to improve quality of care, understand different perspectives, and act as a resource for others; and (c) nurses supporting and facilitating patient-centered ethical decision making. Findings are consistent with those appearing in the international literature but provide a more cohesive and comprehensive account than previously, and hold promise for the development of educational and policy strategies to address moral

  6. The primary structure of fatty-acid-binding protein from nurse shark liver. Structural and evolutionary relationship to the mammalian fatty-acid-binding protein family.

    Science.gov (United States)

    Medzihradszky, K F; Gibson, B W; Kaur, S; Yu, Z H; Medzihradszky, D; Burlingame, A L; Bass, N M

    1992-02-01

    The primary structure of a fatty-acid-binding protein (FABP) isolated from the liver of the nurse shark (Ginglymostoma cirratum) was determined by high-performance tandem mass spectrometry (employing multichannel array detection) and Edman degradation. Shark liver FABP consists of 132 amino acids with an acetylated N-terminal valine. The chemical molecular mass of the intact protein determined by electrospray ionization mass spectrometry (Mr = 15124 +/- 2.5) was in good agreement with that calculated from the amino acid sequence (Mr = 15121.3). The amino acid sequence of shark liver FABP displays significantly greater similarity to the FABP expressed in mammalian heart, peripheral nerve myelin and adipose tissue (61-53% sequence similarity) than to the FABP expressed in mammalian liver (22% similarity). Phylogenetic trees derived from the comparison of the shark liver FABP amino acid sequence with the members of the mammalian fatty-acid/retinoid-binding protein gene family indicate the initial divergence of an ancestral gene into two major subfamilies: one comprising the genes for mammalian liver FABP and gastrotropin, the other comprising the genes for mammalian cellular retinol-binding proteins I and II, cellular retinoic-acid-binding protein myelin P2 protein, adipocyte FABP, heart FABP and shark liver FABP, the latter having diverged from the ancestral gene that ultimately gave rise to the present day mammalian heart-FABP, adipocyte FABP and myelin P2 protein sequences. The sequence for intestinal FABP from the rat could be assigned to either subfamily, depending on the approach used for phylogenetic tree construction, but clearly diverged at a relatively early evolutionary time point. Indeed, sequences proximately ancestral or closely related to mammalian intestinal FABP, liver FABP, gastrotropin and the retinoid-binding group of proteins appear to have arisen prior to the divergence of shark liver FABP and should therefore also be present in elasmobranchs

  7. Shark Detectives

    Science.gov (United States)

    Hitt, Dia

    2005-01-01

    Oceans are often considered mysterious, fascinating places filled with unique and scary animals. One of the most misunderstood and therefore scariest animals is the shark, yet the whale shark, the world's largest fish, is considered harmless to humans. This student-directed activity involves research, deductive reasoning, and students' own…

  8. Isolation and characterization of major histocompatibility complex class IIB genes from the nurse shark.

    OpenAIRE

    Bartl, S; Weissman, I L

    1994-01-01

    The major histocompatibility complex (MHC) contains a set of linked genes which encode cell surface proteins involved in the binding of small peptide antigens for their subsequent recognition by T lymphocytes. MHC proteins share structural features and the presence and location of polymorphic residues which play a role in the binding of antigens. In order to compare the structure of these molecules and gain insights into their evolution, we have isolated two MHC class IIB genes from the nurse...

  9. Identification of high-mannose and multiantennary complex-type N-linked glycans containing alpha-galactose epitopes from Nurse shark IgM heavy chain.

    Science.gov (United States)

    Harvey, David J; Crispin, Max; Moffatt, Beryl E; Smith, Sylvia L; Sim, Robert B; Rudd, Pauline M; Dwek, Raymond A

    2009-11-01

    MALDI-TOF mass spectrometry, negative ion nano-electrospray MS/MS and exoglycosidase digestion were used to identify 36 N-linked glycans from 19S IgM heavy chain derived from the nurse shark (Ginglymostoma cirratum). The major glycan was the high-mannose compound, Man(6)GlcNAc(2) accompanied by small amounts of Man(5)GlcNAc(2), Man(7)GlcNAc(2) and Man(8)GlcNAc(2). Bi- and tri-antennary (isomer with a branched 3-antenna) complex-type glycans were also abundant, most contained a bisecting GlcNAc residue (beta1-->4-linked to the central mannose) and with varying numbers of alpha-galactose residues capping the antennae. Small amounts of monosialylated glycans were also found. This appears to be the first comprehensive study of glycosylation in this species of animal. The glycosylation pattern has implications for the mechanism of activation of the complement system by nurse shark IgM.

  10. Cross matching of blood in carcharhiniform, lamniform, and orectolobiform sharks.

    Science.gov (United States)

    Hadfield, Catherine A; Haines, Ashley N; Clayton, Leigh A; Whitaker, Brent R

    2010-09-01

    The transfusion of whole blood in elasmobranchs could provide cardiovascular support following hemorrhage. Since donor and recipient compatibility is not known, a technique was established to allow cross matching of red blood cells and serum in sharks. Cross matching was carried out among 19 individuals from seven species: the nurse shark (Ginglymostoma cirratum), sandbar shark (Carcharhinus plumbeus), sandtiger shark (Carcharias taurus), white-spotted bamboo shark (Chiloscyllium plagiosum), brown-banded bamboo shark (Chiloscyllium punctatum), zebra shark (Stegostoma fasciatum), and spotted wobbegong (Orectolobus maculatus). Negative cross-matches showed no agglutination or hemolysis, suggesting that donor and recipient would be compatible. Cross-matches between conspecifics were all negative (sandbar, sandtiger, nurse, and white-spotted bamboo sharks). All cross-matches between sandbar and sandtiger sharks were also negative. Positive crossmatches consisted of agglutination or hemolysis of red blood cells, suggesting that the donor and recipient would be incompatible. Strong positive reactions occurred, for example, with red blood cells from sandtiger and sandbar sharks and serum from nurse sharks. Cross matching should be carried out in elasmobranchs prior to any blood transfusion.

  11. Molecular and expression analysis of complement component C5 in the nurse shark (Ginglymostoma cirratum) and its predicted functional role.

    Science.gov (United States)

    Graham, Matthew; Shin, Dong-Ho; Smith, Sylvia L

    2009-07-01

    We present the complete cDNA sequence of shark (Ginglymostoma cirratum) pro-C5 and its molecular characterization with a descriptive analysis of the structural elements necessary for its potential functional role as a potent mediator of inflammation (fragment C5a) and initiator molecule (fragment C5b) for the assembly of the membrane attack complex (MAC) upon activation by C5 convertase. In mammals the three complement activation cascades, the classical, alternative and lectin pathways, converge at the activation of C3, a pivotal complement protein. It is, however, the subsequent activation of the next complement component, C5, which is the focal point at which the initiation of the terminal lytic pathway takes place and involves the stepwise assembly of the MAC. The effector cytolytic function of complement occurs with the insertion of MAC into target membranes causing dough-nut like holes and cell leakage. The lytic activity of shark complement results in structurally similar holes in target membranes suggesting the assembly of a shark MAC that likely involves a functional analogue of C5. The composition of shark MAC remains unresolved and to date conclusive evidence has been lacking for shark C5. The gene has not been cloned nor has the serum protein been characterized for any elasmobranch species. This report is the first to confirm the presence of C5 homologue in the shark. GcC5 is remarkably similar to human C5 in overall structure and domain arrangement. The GcC5 cDNA measured 5160-bp with 5' and 3' UTRs of 35 bp and 79 bp, respectively. Structural analysis of the derived protein sequence predicts a molecule that is a two-chain structure which lacks a thiolester bond and contains a C5 convertase cleavage site indicating that activation will generate two peptides, akin to C5b and C5a. The putative GcC5 molecule also contains the C-terminal C345C/Netrin module that characterizes C3, C4 and C5. Multiple alignment of deduced amino acid sequences shows that GcC5

  12. Residency and spatial use by reef sharks of an isolated seamount and its implications for conservation.

    Science.gov (United States)

    Barnett, Adam; Abrantes, Kátya G; Seymour, Jamie; Fitzpatrick, Richard

    2012-01-01

    Although marine protected areas (MPAs) are a common conservation strategy, these areas are often designed with little prior knowledge of the spatial behaviour of the species they are designed to protect. Currently, the Coral Sea area and its seamounts (north-east Australia) are under review to determine if MPAs are warranted. The protection of sharks at these seamounts should be an integral component of conservation plans. Therefore, knowledge on the spatial ecology of sharks at the Coral Sea seamounts is essential for the appropriate implementation of management and conservation plans. Acoustic telemetry was used to determine residency, site fidelity and spatial use of three shark species at Osprey Reef: whitetip reef sharks Triaenodon obesus, grey reef sharks Carcharhinus amblyrhynchos and silvertip sharks Carcharhinus albimarginatus. Most individuals showed year round residency at Osprey Reef, although five of the 49 individuals tagged moved to the neighbouring Shark Reef (~14 km away) and one grey reef shark completed a round trip of ~250 km to the Great Barrier Reef. Additionally, individuals of white tip and grey reef sharks showed strong site fidelity to the areas they were tagged, and there was low spatial overlap between groups of sharks tagged at different locations. Spatial use at Osprey Reef by adult sharks is generally restricted to the north-west corner. The high residency and limited spatial use of Osprey Reef suggests that reef sharks would be highly vulnerable to targeted fishing pressure and that MPAs incorporating no-take of sharks would be effective in protecting reef shark populations at Osprey and Shark Reef.

  13. Residency and spatial use by reef sharks of an isolated seamount and its implications for conservation.

    Directory of Open Access Journals (Sweden)

    Adam Barnett

    Full Text Available Although marine protected areas (MPAs are a common conservation strategy, these areas are often designed with little prior knowledge of the spatial behaviour of the species they are designed to protect. Currently, the Coral Sea area and its seamounts (north-east Australia are under review to determine if MPAs are warranted. The protection of sharks at these seamounts should be an integral component of conservation plans. Therefore, knowledge on the spatial ecology of sharks at the Coral Sea seamounts is essential for the appropriate implementation of management and conservation plans. Acoustic telemetry was used to determine residency, site fidelity and spatial use of three shark species at Osprey Reef: whitetip reef sharks Triaenodon obesus, grey reef sharks Carcharhinus amblyrhynchos and silvertip sharks Carcharhinus albimarginatus. Most individuals showed year round residency at Osprey Reef, although five of the 49 individuals tagged moved to the neighbouring Shark Reef (~14 km away and one grey reef shark completed a round trip of ~250 km to the Great Barrier Reef. Additionally, individuals of white tip and grey reef sharks showed strong site fidelity to the areas they were tagged, and there was low spatial overlap between groups of sharks tagged at different locations. Spatial use at Osprey Reef by adult sharks is generally restricted to the north-west corner. The high residency and limited spatial use of Osprey Reef suggests that reef sharks would be highly vulnerable to targeted fishing pressure and that MPAs incorporating no-take of sharks would be effective in protecting reef shark populations at Osprey and Shark Reef.

  14. Residency and Spatial Use by Reef Sharks of an Isolated Seamount and Its Implications for Conservation

    Science.gov (United States)

    Barnett, Adam; Abrantes, Kátya G.; Seymour, Jamie; Fitzpatrick, Richard

    2012-01-01

    Although marine protected areas (MPAs) are a common conservation strategy, these areas are often designed with little prior knowledge of the spatial behaviour of the species they are designed to protect. Currently, the Coral Sea area and its seamounts (north-east Australia) are under review to determine if MPAs are warranted. The protection of sharks at these seamounts should be an integral component of conservation plans. Therefore, knowledge on the spatial ecology of sharks at the Coral Sea seamounts is essential for the appropriate implementation of management and conservation plans. Acoustic telemetry was used to determine residency, site fidelity and spatial use of three shark species at Osprey Reef: whitetip reef sharks Triaenodon obesus, grey reef sharks Carcharhinus amblyrhynchos and silvertip sharks Carcharhinus albimarginatus. Most individuals showed year round residency at Osprey Reef, although five of the 49 individuals tagged moved to the neighbouring Shark Reef (∼14 km away) and one grey reef shark completed a round trip of ∼250 km to the Great Barrier Reef. Additionally, individuals of white tip and grey reef sharks showed strong site fidelity to the areas they were tagged, and there was low spatial overlap between groups of sharks tagged at different locations. Spatial use at Osprey Reef by adult sharks is generally restricted to the north-west corner. The high residency and limited spatial use of Osprey Reef suggests that reef sharks would be highly vulnerable to targeted fishing pressure and that MPAs incorporating no-take of sharks would be effective in protecting reef shark populations at Osprey and Shark Reef. PMID:22615782

  15. A comparison of mode of attachment and histopathogenicity of four tapeworm species representing two orders infecting the spiral intestine of the nurse shark, Ginglymostoma cirratum.

    Science.gov (United States)

    Borucinska, J; Caira, J N

    1993-04-01

    This study was undertaken to compare 2 species of Tetraphyllidea and 2 species of Trypanorhyncha with regard to the relationship between attachment structure morphology, mode of attachment, and tapeworm size, to damage at the sites of attachment in the Atlantic nurse shark, Ginglymostoma cirratum. Regions of the spiral intestine with worms attached were removed from 8 nurse sharks and sectioned according to conventional techniques. Sections of 5-50 specimens of each tapeworm species were examined. Regions of the spiral intestine devoid of worms were processed for characterization of the normal mucosa. The normal mucosa was found to consist of a folded surface covered with round-to-oval primary mucosal crypts. In the first 7 or 8 chambers of the spiral intestine the mucosal surface was thrown into secondary folds, forming ridges and secondary crypts. The primary mucosal crypts were lined with a single layer of columnar epithelium resting on a basement membrane. A highly cellular lamina propria and submucosa were found between the crypts and the muscularis mucosa. The small tetraphyllidean Pedibothrium brevispine was found with its scolex lying within the primary mucosal crypts with its hooks embedded in the basement membrane. Epithelial denudation was evident. The large tetraphyllidean Pedibothrium globicephalum was found with its bothridia engulfing large portions of the mucosa and its hooks embedded into the lamina propria. It was associated with moderate to severe mucosal necrosis. The small trypanorhynch Prochristianella tenuispine was found lying between the mucosal ridges in the secondary crypts with its tentacles either penetrating the epithelium, or occasionally, the lamina propria.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Construction of a nurse shark (Ginglymostoma cirratum) bacterial artificial chromosome (BAC) library and a preliminary genome survey

    OpenAIRE

    Luo, Meizhong; Kim, HyeRan; Kudrna, Dave; Sisneros, Nicholas B; Lee, So-Jeong; Mueller, Christopher; Collura, Kristi; Zuccolo, Andrea; Buckingham, E Bryan; Grim, Suzanne M; Yanagiya, Kazuyo; Inoko, Hidetoshi; Shiina, Takashi; Flajnik, Martin F; Wing, Rod A

    2006-01-01

    Abstract Background Sharks are members of the taxonomic class Chondrichthyes, the oldest living jawed vertebrates. Genomic studies of this group, in comparison to representative species in other vertebrate taxa, will allow us to theorize about the fundamental genetic, developmental, and functional characteristics in the common ancestor of all jawed vertebrates. Aims In order to obtain mapping and sequencing data for comparative genomics, we constructed a bacterial artificial chromosome (BAC) ...

  17. 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.

    Science.gov (United States)

    Davidson, Bruce; Sidell, Jonathan; Rhodes, Jeffrey; Cliff, Geremy

    2011-03-01

    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 there was generally little variation between the species, all species showed profiles rich in both n6 and n3 polyunsaturated fatty acids compared to terrestrial commercial meats that have low n3. Thus, utilizing skeletal muscle tissues from sharks caught as part of the bycatch when fishing for teleosts would avoid unnecessary wastage of a potentially valuable resource, with all the possible health benefits of high quality protein combined with balanced polyunsaturates, although contamination with high levels of metabolic wastes, such as urea, may be a negative consideration.

  18. Somatic hypermutation of the new antigen receptor gene (NAR) in the nurse shark does not generate the repertoire: possible role in antigen-driven reactions in the absence of germinal centers.

    Science.gov (United States)

    Diaz, M; Greenberg, A S; Flajnik, M F

    1998-11-24

    The new antigen receptor (NAR) gene in the nurse shark diversifies extensively by somatic hypermutation. It is not known, however, whether NAR somatic hypermutation generates the primary repertoire (like in the sheep) or rather is used in antigen-driven immune responses. To address this issue, the sequences of NAR transmembrane (Tm) and secretory (Sec) forms, presumed to represent the primary and secondary repertoires, respectively, were examined from the peripheral blood lymphocytes of three adult nurse sharks. More than 40% of the Sec clones but fewer than 11% of Tm clones contained five mutations or more. Furthermore, more than 75% of the Tm clones had few or no mutations. Mutations in the Sec clones occurred mostly in the complementarity-determining regions (CDR) with a significant bias toward replacement substitutions in CDR1; in Tm clones there was no significant bias toward replacements and only a low level of targeting to the CDRs. Unlike the Tm clones where the replacement mutational pattern was similar to that seen for synonymous changes, Sec replacements displayed a distinct pattern of mutations. The types of mutations in NAR were similar to those found in mouse Ig genes rather than to the unusual pattern reported for shark and Xenopus Ig. Finally, an oligoclonal family of Sec clones revealed a striking trend toward acquisition of glutamic/aspartic acid, suggesting some degree of selection. These data strongly suggest that hypermutation of NAR does not generate the repertoire, but instead is involved in antigen-driven immune responses.

  19. Field hearing measurements of the Atlantic sharpnose shark Rhizoprionodon terraenovae.

    Science.gov (United States)

    Casper, B M; Mann, D A

    2009-12-01

    Field measurements of hearing thresholds were obtained from the Atlantic sharpnose shark Rhizoprionodon terraenovae using the auditory evoked potential method (AEP). The fish had most sensitive hearing at 20 Hz, the lowest frequency tested, with decreasing sensitivity at higher frequencies. Hearing thresholds were lower than AEP thresholds previously measured for the nurse shark Ginglymostoma cirratum and yellow stingray Urobatis jamaicensis at frequencies sharks which have been observed in acoustic field attraction experiments. The sound pressure levels that would be equivalent to the particle acceleration thresholds of R. terraenovae were much higher than the sound levels which attracted closely related sharks suggesting a discrepancy between the hearing threshold experiments and the field attraction experiments.

  20. SHARK LONGLINE FISHERY IN TANJUNGLUAR-EAST LOMBOK

    Directory of Open Access Journals (Sweden)

    Dharmadi Dharmadi

    2013-06-01

    longline fishing was conducted every month. The trend of shark catches relates to the number of fishing vessels, fishing ground, and weather conditions at sea. The period between July and September is a transitional season from East to West seasons. During this season, the wind strength is weakened and a good fishing season for the fishers. The lowest catch occurs in January (1.06 tonnes and the highest catch in September with the total catch of 24.6 tonnes. Sharks caught by surface longline were dominated by Silky shark, Carcharhinus falciformis (40-90% with the size range of 100-125 cm. The catch of bottom longline was mostly consisting of fish in mature condition that dominated by Grey reef shark (Carcharhinus amblyrhynchos, Common black tip shark (C. limbatus, Spot tail shark (C. sorrah, and Scalloped hammerhead shark (Sphyrna lewini, with the size range of 125-200 cm, 170- 250 cm, 100-150 cm, and 170-300 cm, respectively. Surface longline fishing occurs in the offshore waters in depth more than 200 m to 3000 m, whereas bottom longline fishing is operated at a depth of 50-100 m around islands.

  1. "Grey matters".

    Science.gov (United States)

    Rose, Katie

    2014-01-01

    It's common in this world, for diagnoses to be confused. This grey, oblique world is the "World of Brain Tumors" from which these narratives are written, a world I entered when a tangerine-sized tumor was found on my temporal lobe. Each narrative illustrates this world in which everything is covered in a thick film rendering things once obvious, now unknown. Parents are asked to choose treatment plans for their children, plans that will inevitably alter their child's quality of life but in ways they cannot determine or even imagine. Parents are asked to play God. Most of the parents who share their stories in this collection, parents of PBT (pediatric brain tumor) patients have to walk the line of trying to not disrupt their relationships with their physicians, wanting the best for their child, and facing the decision to follow their gut or go with advised treatment plans.

  2. Instant BrainShark

    CERN Document Server

    Li, Daniel

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. ""Instant BrainShark"" is a step-by-step guide to creating online presentations using BrainShark. The book covers digital marketing best practices alongside tips for sales conversions. The book is written in an easy-to-read style for anybody to easily pick up and get started with BrainShark.Instant BrainShark is for anyone who wants to use BrainShark to create presentations online and share them around the community. The book is also useful for developers who are looking to explore

  3. Quantifying shark distribution patterns and species-habitat associations: implications of marine park zoning.

    Science.gov (United States)

    Espinoza, Mario; Cappo, Mike; Heupel, Michelle R; Tobin, Andrew J; Simpfendorfer, Colin A

    2014-01-01

    Quantifying shark distribution patterns and species-specific habitat associations in response to geographic and environmental drivers is critical to assessing risk of exposure to fishing, habitat degradation, and the effects of climate change. The present study examined shark distribution patterns, species-habitat associations, and marine reserve use with baited remote underwater video stations (BRUVS) along the entire Great Barrier Reef Marine Park (GBRMP) over a ten year period. Overall, 21 species of sharks from five families and two orders were recorded. Grey reef Carcharhinus amblyrhynchos, silvertip C. albimarginatus, tiger Galeocerdo cuvier, and sliteye Loxodon macrorhinus sharks were the most abundant species (>64% of shark abundances). Multivariate regression trees showed that hard coral cover produced the primary split separating shark assemblages. Four indicator species had consistently higher abundances and contributed to explaining most of the differences in shark assemblages: C. amblyrhynchos, C. albimarginatus, G. cuvier, and whitetip reef Triaenodon obesus sharks. Relative distance along the GBRMP had the greatest influence on shark occurrence and species richness, which increased at both ends of the sampling range (southern and northern sites) relative to intermediate latitudes. Hard coral cover and distance across the shelf were also important predictors of shark distribution. The relative abundance of sharks was significantly higher in non-fished sites, highlighting the conservation value and benefits of the GBRMP zoning. However, our results also showed that hard coral cover had a large effect on the abundance of reef-associated shark species, indicating that coral reef health may be important for the success of marine protected areas. Therefore, understanding shark distribution patterns, species-habitat associations, and the drivers responsible for those patterns is essential for developing sound management and conservation approaches.

  4. The development of primary and secondary lymphoid tissues in the nurse shark Ginglymostoma cirratum: B-cell zones precede dendritic cell immigration and T-cell zone formation during ontogeny of the spleen.

    Science.gov (United States)

    Rumfelt, L L; McKinney, E C; Taylor, E; Flajnik, M F

    2002-08-01

    Secondary lymphoid tissue and immunoglobulin (Ig) production in mammals is not fully developed at birth, requiring time postnatally to attain all features required for adaptive immune responses. The immune system of newborn sharks - the oldest vertebrate group having adaptive immunity - also displays immature characteristics such as low serum IgM concentration and high levels of IgM1gj, an innate-like Ig. Primary and secondary lymphoid tissues in sharks and other cartilaginous fish were identified previously, but their cellular organization was not examined in detail. In this study of nurse shark lymphoid tissue, we demonstrate that the adult spleen contains well-defined, highly vascularized white pulp (WP) areas, composed of a central T-cell zone containing a major histocompatibility complex (MHC) class II+ dendritic cell (DC) network and a small number of Ig+ secretory cells, surrounded by smaller zones of surface Ig+ (sIg+) B cells. In neonates, splenic WPs are exclusively B-cell zones containing sIgM+-MHC class IIlow B cells; thus compartmentalized areas with T cells and DCs, as well as surface Ig novel antigen receptor (sIgNAR)-expressing B cells are absent at birth. Not until the pups are 5 months old do these WP areas become adult-like; concomitantly, sIgNAR+ B cells are readily detectable, indicating that this Ig class requires a 'mature immune-responsive environment'. The epigonal organ is the major site of neonatal B lymphopoiesis, based on the presence of developing B cells and recombination-activating gene 1 (RAG1)/terminal deoxynucleotidyl transferase (TdT) expression, indicative of antigen receptor rearrangement; such expression persists into adult life, whereas the spleen has negligible lymphopoietic activity. In adults but not neonates, many secretory B cells reside in the epigonal organ, suggesting, like in mammals, that B cells home to this primary lymphoid tissue after activation in other areas of the body.

  5. The Greenland shark

    DEFF Research Database (Denmark)

    Costantini, David; Smith, Shona; Killen, Shaun S.

    2017-01-01

    the oxidative status of the Greenland shark (Somniosus microcephalus), which has recently been found as the longest living vertebrate animal known to science with a lifespan of at least 272years. As compared to other species, the Greenland shark had body mass-corrected values of muscle glutathione peroxidase...... that the values of metrics of oxidative status we measured might be linked to ecological features (e.g., adaptation to cold waters and deep dives) of this shark species rather to its lifespan....

  6. Acoustic telemetry validates a citizen science approach for monitoring sharks on coral reefs.

    Science.gov (United States)

    Vianna, Gabriel M S; Meekan, Mark G; Bornovski, Tova H; Meeuwig, Jessica J

    2014-01-01

    Citizen science is promoted as a simple and cost-effective alternative to traditional approaches for the monitoring of populations of marine megafauna. However, the reliability of datasets collected by these initiatives often remains poorly quantified. We compared datasets of shark counts collected by professional dive guides with acoustic telemetry data from tagged sharks collected at the same coral reef sites over a period of five years. There was a strong correlation between the number of grey reef sharks (Carcharhinus amblyrhynchos) observed by dive guides and the telemetry data at both daily and monthly intervals, suggesting that variation in relative abundance of sharks was detectable in datasets collected by dive guides in a similar manner to data derived from telemetry at these time scales. There was no correlation between the number or mean depth of sharks recorded by telemetry and the presence of tourist divers, suggesting that the behaviour of sharks was not affected by the presence of divers during our study. Data recorded by dive guides showed that current strength and temperature were important drivers of the relative abundance of sharks at monitored sites. Our study validates the use of datasets of shark abundance collected by professional dive guides in frequently-visited dive sites in Palau, and supports the participation of experienced recreational divers as contributors to long-term monitoring programs of shark populations.

  7. Mutational pattern of the nurse shark antigen receptor gene (NAR) is similar to that of mammalian Ig genes and to spontaneous mutations in evolution: the translesion synthesis model of somatic hypermutation.

    Science.gov (United States)

    Diaz, M; Velez, J; Singh, M; Cerny, J; Flajnik, M F

    1999-05-01

    The pattern of somatic mutations of shark and frog Ig is distinct from somatic hypermutation of Ig in mammals in that there is a bias to mutate GC base pairs and a low frequency of mutations. Previous analysis of the new antigen receptor gene in nurse sharks (NAR), however, revealed no bias to mutate GC base pairs and the frequency of mutation was comparable to that of mammalian IgG. Here, we analyzed 1023 mutations in NAR and found no targeting of the mechanism to any particular nucleotide but did obtain strong evidence for a transition bias and for strand polarity. As seen for all species studied to date, the serine codon AGC/T in NAR was a mutational hotspot. The NAR mutational pattern is most similar to that of mammalian IgG and furthermore both are strikingly akin to mutations acquired during the neutral evolution of nuclear pseudogenes, suggesting that a similar mechanism is at work for both processes. In yeast, most spontaneous mutations are introduced by the translesion synthesis DNA polymerase zeta (REV3) and in various DNA repair-deficient backgrounds transitions were more often REV3-dependent than were transversions. Therefore, we propose a model of somatic hypermutation where DNA polymerase zeta is recruited to the Ig locus. An excess of DNA glycosylases in germinal center reactions may further enhance the mutation frequency by a REV3-dependent mutagenic process known as imbalanced base excision repair.

  8. Predicting occurrence of juvenile shark habitat to improve conservation planning.

    Science.gov (United States)

    Oh, Beverly Z L; Sequeira, Ana M M; Meekan, Mark G; Ruppert, Jonathan L W; Meeuwig, Jessica J

    2017-06-01

    Fishing and habitat degradation have increased the extinction risk of sharks, and conservation strategies recognize that survival of juveniles is critical for the effective management of shark populations. Despite the rapid expansion of marine protected areas (MPAs) globally, the paucity of shark-monitoring data on large scales (100s-1000s km) means that the effectiveness of MPAs in halting shark declines remains unclear. Using data collected by baited remote underwater video systems (BRUVS) in northwestern Australia, we developed generalized linear models to elucidate the ecological drivers of habitat suitability for juvenile sharks. We assessed occurrence patterns at the order and species levels. We included all juvenile sharks sampled and the 3 most abundant species sampled separately (grey reef [Carcharhinus amblyrhynchos], sandbar [Carcharhinus plumbeus], and whitetip reef sharks [Triaenodon obesus]). We predicted the occurrence of juvenile sharks across 490,515 km 2 of coastal waters and quantified the representation of highly suitable habitats within MPAs. Our species-level models had higher accuracy (ĸ ≥ 0.69) and deviance explained (≥48%) than our order-level model (ĸ = 0.36 and deviance explained of 10%). Maps of predicted occurrence revealed different species-specific patterns of highly suitable habitat. These differences likely reflect different physiological or resource requirements between individual species and validate concerns over the utility of conservation targets based on aggregate species groups as opposed to a species-focused approach. Highly suitable habitats were poorly represented in MPAs with the most restrictions on extractive activities. This spatial mismatch possibly indicates a lack of explicit conservation targets and information on species distribution during the planning process. Non-extractive BRUVS provided a useful platform for building the suitability models across large scales to assist conservation planning across

  9. Shark attacks in Dakar and the Cap Vert Peninsula, Senegal: low incidence despite high occurrence of potentially dangerous species.

    Science.gov (United States)

    Trape, Sébastien

    2008-01-30

    The International Shark Attack File mentions only four unprovoked shark attacks on the coast of West Africa during the period 1828-2004, an area where high concentrations of sharks and 17 species potentially dangerous to man have been observed. To investigate if the frequency of shark attacks could be really low and not just under-reported and whether there are potentially sharks that might attack in the area, a study was carried out in Dakar and the Cap Vert peninsula, Senegal. Personnel of health facilities, administrative services, traditional authorities and groups of fishermen from the region of Dakar were interviewed about the occurrence of shark attacks, and visual censuses were conducted along the coastline to investigate shark communities associated with the coasts of Dakar and the Cap Vert peninsula. Six attacks were documented for the period 1947-2005, including two fatal ones attributed to the tiger shark Galeocerdo cuvieri. All attacks concerned fishermen and only one occurred after 1970. Sharks were observed year round along the coastline in waters 3-15 m depth. Two species potentially dangerous for man, the nurse shark Ginglymostoma cirratum and the blacktip shark Carcharhinus limbatus, represented together 94% of 1,071 sharks enumerated during 1,459 hours of observations. Threatening behaviour from sharks was noted in 12 encounters (1.1%), including 8 encounters with C. limbatus, one with Galeocerdo cuvieri and 3 with unidentified sharks. These findings suggest that the frequency of shark attacks on the coast of West Africa is underestimated. However, they also indicate that the risk is very low despite the abundance of sharks. In Dakar area, most encounters along the coastline with potentially dangerous species do not result in an attack. Compared to other causes of water related deaths, the incidence of shark attack appears negligible, at least one thousand fold lower.

  10. Shark attacks in Dakar and the Cap Vert Peninsula, Senegal: low incidence despite high occurrence of potentially dangerous species.

    Directory of Open Access Journals (Sweden)

    Sébastien Trape

    Full Text Available BACKGROUND: The International Shark Attack File mentions only four unprovoked shark attacks on the coast of West Africa during the period 1828-2004, an area where high concentrations of sharks and 17 species potentially dangerous to man have been observed. To investigate if the frequency of shark attacks could be really low and not just under-reported and whether there are potentially sharks that might attack in the area, a study was carried out in Dakar and the Cap Vert peninsula, Senegal. METHODOLOGY/PRINCIPAL FINDINGS: Personnel of health facilities, administrative services, traditional authorities and groups of fishermen from the region of Dakar were interviewed about the occurrence of shark attacks, and visual censuses were conducted along the coastline to investigate shark communities associated with the coasts of Dakar and the Cap Vert peninsula. Six attacks were documented for the period 1947-2005, including two fatal ones attributed to the tiger shark Galeocerdo cuvieri. All attacks concerned fishermen and only one occurred after 1970. Sharks were observed year round along the coastline in waters 3-15 m depth. Two species potentially dangerous for man, the nurse shark Ginglymostoma cirratum and the blacktip shark Carcharhinus limbatus, represented together 94% of 1,071 sharks enumerated during 1,459 hours of observations. Threatening behaviour from sharks was noted in 12 encounters (1.1%, including 8 encounters with C. limbatus, one with Galeocerdo cuvieri and 3 with unidentified sharks. CONCLUSIONS/SIGNIFICANCE: These findings suggest that the frequency of shark attacks on the coast of West Africa is underestimated. However, they also indicate that the risk is very low despite the abundance of sharks. In Dakar area, most encounters along the coastline with potentially dangerous species do not result in an attack. Compared to other causes of water related deaths, the incidence of shark attack appears negligible, at least one thousand

  11. Disinfection of grey water

    OpenAIRE

    Winward, Gideon Paul

    2007-01-01

    The reuse of grey water, for applications such as toilet flushing and irrigation, represents a potential sustainable solution to water shortages experienced by regions worldwide. Although reused grey water is not intended for potable use, the potential for transmission of waterborne pathogens by aerosol inhalation, topical contact, or indirect ingestion is a key concern for grey water reuse. This thesis explores the pathogen content of grey water and investigates pathogen remov...

  12. Grey water biodegradability

    NARCIS (Netherlands)

    Abu Ghunmi, L.; Zeeman, G.; Fayyad, M.; Van Lier, J.B.

    2010-01-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different

  13. Grey water biodegradability

    NARCIS (Netherlands)

    Abu Ghunmi, L.; Zeeman, G.; Fayyad, M.; Lier, van J.B.

    2011-01-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different

  14. Proteasome, transporter associated with antigen processing, and class I genes in the nurse shark Ginglymostoma cirratum: evidence for a stable class I region and MHC haplotype lineages.

    Science.gov (United States)

    Ohta, Yuko; McKinney, E Churchill; Criscitiello, Michael F; Flajnik, Martin F

    2002-01-15

    Cartilaginous fish (e.g., sharks) are derived from the oldest vertebrate ancestor having an adaptive immune system, and thus are key models for examining MHC evolution. Previously, family studies in two shark species showed that classical class I (UAA) and class II genes are genetically linked. In this study, we show that proteasome genes LMP2 and LMP7, shark-specific LMP7-like, and the TAP1/2 genes are linked to class I/II. Functional LMP7 and LMP7-like genes, as well as multiple LMP2 genes or gene fragments, are found only in some sharks, suggesting that different sets of peptides might be generated depending upon inherited MHC haplotypes. Cosmid clones bearing the MHC-linked classical class I genes were isolated and shown to contain proteasome gene fragments. A non-MHC-linked LMP7 gene also was identified on another cosmid, but only two exons of this gene were detected, closely linked to a class I pseudogene (UAA-NC2); this region probably resulted from a recent duplication and translocation from the functional MHC. Tight linkage of proteasome and class I genes, in comparison with gene organizations of other vertebrates, suggests a primordial MHC organization. Another nonclassical class I gene (UAA-NC1) was detected that is linked neither to MHC nor to UAA-NC2; its high level of sequence similarity to UAA suggests that UAA-NC1 also was recently derived from UAA and translocated from MHC. These data further support the principle of a primordial class I region with few class I genes. Finally, multiple paternities in one family were demonstrated, with potential segregation distortions.

  15. Structure and dynamics of the shark assemblage off Recife, Northeastern Brazil.

    Science.gov (United States)

    Afonso, André S; Andrade, Humber A; Hazin, Fábio H V

    2014-01-01

    Understanding the ecological factors that regulate elasmobranch abundance in nearshore waters is essential to effectively manage coastal ecosystems and promote conservation. However, little is known about elasmobranch populations in the western South Atlantic Ocean. An 8-year, standardized longline and drumline survey conducted in nearshore waters off Recife, northeastern Brazil, allowed us to describe the shark assemblage and to monitor abundance dynamics using zero-inflated generalized additive models. This region is mostly used by several carcharhinids and one ginglymostomid, but sphyrnids are also present. Blacknose sharks, Carcharhinus acronotus, were mostly mature individuals and declined in abundance throughout the survey, contrasting with nurse sharks, Ginglymostoma cirratum, which proliferated possibly due to this species being prohibited from all harvest since 2004 in this region. Tiger sharks, Galeocerdo cuvier, were mostly juveniles smaller than 200 cm and seem to use nearshore waters off Recife between January and September. No long-term trend in tiger shark abundance was discernible. Spatial distribution was similar in true coastal species (i.e. blacknose and nurse sharks) whereas tiger sharks were most abundant at the middle continental shelf. The sea surface temperature, tidal amplitude, wind direction, water turbidity, and pluviosity were all selected to predict shark abundance off Recife. Interspecific variability in abundance dynamics across spatiotemporal and environmental gradients suggest that the ecological processes regulating shark abundance are generally independent between species, which could add complexity to multi-species fisheries management frameworks. Yet, further research is warranted to ascertain trends at population levels in the South Atlantic Ocean.

  16. How to search for and use 'grey literature' in research.

    Science.gov (United States)

    Coad, Jane; Hardicre, Jayne; Devitt, Patric

    An ever-growing amount of grey literature is available to nurses, including oral presentations, personal communication, leaflets, newspapers and magazines, unpublished research, internal reports and minutes of meetings. It can be an invaluable research resource.

  17. Place learning prior to and after telencephalon ablation in bamboo and coral cat sharks (Chiloscyllium griseum and Atelomycterus marmoratus).

    Science.gov (United States)

    Fuss, Theodora; Bleckmann, Horst; Schluessel, Vera

    2014-01-01

    This study assessed complex spatial learning and memory in two species of shark, the grey bamboo shark (Chiloscyllium griseum) and the coral cat shark (Atelomycterus marmoratus). It was hypothesized that sharks can learn and apply an allocentric orientation strategy. Eight out of ten sharks successfully completed the initial training phase (by locating a fixed goal position in a diamond maze from two possible start points) within 14.9 ± 7.6 sessions and proceeded to seven sets of transfer tests, in which sharks had to perform under altered environmental conditions. Transfer tests revealed that sharks had oriented and solved the tasks visually, using all of the provided environmental cues. Unintentional cueing did not occur. Results correspond to earlier studies on spatial memory and cognitive mapping in other vertebrates. Future experiments should investigate whether sharks possess a cognitive spatial mapping system as has already been found in several teleosts and stingrays. Following the completion of transfer tests, sharks were subjected to ablation of most of the pallium, which compromised their previously acquired place learning abilities. These results indicate that the telencephalon plays a crucial role in the processing of information on place learning and allocentric orientation strategies.

  18. Sharks of the order Carcharhiniformes

    National Research Council Canada - National Science Library

    Compagno, L.J.V

    1988-01-01

    This book is a general review, taxonomic revision, and phylogenetic analysis of the carcharhinoids, the largest group of living sharks, which comprises almost 60 percent or 200 of known shark species...

  19. Molecular characterization of the alpha subunit of complement component C8 (GcC8alpha) in the nurse shark (Ginglymostoma cirratum).

    Science.gov (United States)

    Aybar, Lydia; Shin, Dong-Ho; Smith, Sylvia L

    2009-09-01

    Target cell lysis by complement is achieved by the assembly and insertion of the membrane attack complex (MAC) composed of glycoproteins C5b through C9. The lytic activity of shark complement involves functional analogues of mammalian C8 and C9. Mammalian C8 is composed of alpha, beta, and gamma subunits. The subunit structure of shark C8 is not known. This report describes a 2341 nucleotide sequence that translates into a polypeptide of 589 amino acid residues, orthologue to mammalian C8alpha and has the same modular architecture with conserved cysteines forming the peptide bond backbone. The C8gamma-binding cysteine is conserved in the perforin-like domain. Hydrophobicity profile indicates the presence of hydrophobic residues essential for membrane insertion. It shares 41.1% and 47.4% identity with human and Xenopus C8alpha respectively. Southern blot analysis showed GcC8alpha exists as a single copy gene expressed in most tissues except the spleen with the liver being the main site of synthesis. Phylogenetic analysis places it in a clade with C8alpha orthologs and as a sister taxa to the Xenopus. 2009 Elsevier Ltd.

  20. Drivers of abundance and spatial distribution of reef-associated sharks in an isolated atoll reef system.

    Directory of Open Access Journals (Sweden)

    David M Tickler

    Full Text Available We investigated drivers of reef shark demography across a large and isolated marine protected area, the British Indian Ocean Territory Marine Reserve, using stereo baited remote underwater video systems. We modelled shark abundance against biotic and abiotic variables at 35 sites across the reserve and found that the biomass of low trophic order fish (specifically planktivores had the greatest effect on shark abundance, although models also included habitat variables (depth, coral cover and site type. There was significant variation in the composition of the shark assemblage at different atolls within the reserve. In particular, the deepest habitat sampled (a seamount at 70-80m visited for the first time in this study recorded large numbers of scalloped hammerhead sharks (Sphyrna lewini not observed elsewhere. Size structure of the most abundant and common species, grey reef sharks (Carcharhinus amblyrhynchos, varied with location. Individuals at an isolated bank were 30% smaller than those at the main atolls, with size structure significantly biased towards the size range for young of year (YOY. The 18 individuals judged to be YOY represented the offspring of between four and six females, so, whilst inconclusive, these data suggest the possible use of a common pupping site by grey reef sharks. The importance of low trophic order fish biomass (i.e. potential prey in predicting spatial variation in shark abundance is consistent with other studies both in marine and terrestrial systems which suggest that prey availability may be a more important predictor of predator distribution than habitat suitability. This result supports the need for ecosystem level rather than species-specific conservation measures to support shark recovery. The observed spatial partitioning amongst sites for species and life-stages also implies the need to include a diversity of habitats and reef types within a protected area for adequate protection of reef-associated shark

  1. The Dutch Grey Market

    NARCIS (Netherlands)

    Renneboog, L.D.R.; Spaenjers, C.

    2008-01-01

    When-issued trading concerns transactions in securities that have not yet been issued. This type of trade often takes place in a so-called ‘grey market’, in which all contracts are conditional on the issuance of the security. In this paper, we investigate the Dutch grey market for when-issued shares

  2. The Dutch Grey Market

    NARCIS (Netherlands)

    Renneboog, L.D.R.; Spaenjers, C.

    2008-01-01

    When-issued trading concerns transactions in securities that have not yet been issued. This type of trade often takes place in a so-called 'grey market', in which all contracts are conditional on the issuance of the security. In this paper, we investigate the Dutch grey market for when-issued shares

  3. Characteristics of grey wastewater

    DEFF Research Database (Denmark)

    Eriksson, Eva; Auffarth, Karina Pipaluk Solvejg; Henze, Mogens

    2002-01-01

    The composition of grey wastewater depends on sources and installations from where the water is drawn, e.g. kitchen, bathroom or laundry. The chemical compounds present originate from household chemicals, cooking, washing and the piping. In general grey wastewater contains lower levels of organic...

  4. Modulation of shark prey capture kinematics in response to sensory deprivation.

    Science.gov (United States)

    Gardiner, Jayne M; Atema, Jelle; Hueter, Robert E; Motta, Philip J

    2017-02-01

    The ability of predators to modulate prey capture in response to the size, location, and behavior of prey is critical to successful feeding on a variety of prey types. Modulating in response to changes in sensory information may be critical to successful foraging in a variety of environments. Three shark species with different feeding morphologies and behaviors were filmed using high-speed videography while capturing live prey: the ram-feeding blacktip shark, the ram-biting bonnethead, and the suction-feeding nurse shark. Sharks were examined intact and after sensory information was blocked (olfaction, vision, mechanoreception, and electroreception, alone and in combination), to elucidate the contribution of the senses to the kinematics of prey capture. In response to sensory deprivation, the blacktip shark demonstrated the greatest amount of modulation, followed by the nurse shark. In the absence of olfaction, blacktip sharks open the jaws slowly, suggestive of less motivation. Without lateral line cues, blacktip sharks capture prey from greater horizontal angles using increased ram. When visual cues are absent, blacktip sharks elevate the head earlier and to a greater degree, allowing them to overcome imprecise position of the prey relative to the mouth, and capture prey using decreased ram, while suction remains unchanged. When visual cues are absent, nurse sharks open the mouth wider, extend the labial cartilages further, and increase suction while simultaneously decreasing ram. Unlike some bony fish, neither species switches feeding modalities (i.e. from ram to suction or vice versa). Bonnetheads failed to open the mouth when electrosensory cues were blocked, but otherwise little to no modulation was found in this species. These results suggest that prey capture may be less plastic in elasmobranchs than in bony fishes, possibly due to anatomical differences, and that the ability to modulate feeding kinematics in response to available sensory information varies

  5. Variations in gastric acid secretion during periods of fasting between two species of shark.

    Science.gov (United States)

    Papastamatiou, Yannis P; Lowe, Christopher G

    2005-06-01

    Vertebrates differ in their regulation of gastric acid secretion during periods of fasting, yet it is unknown why these differences occur. Elasmobranch fishes are the earliest known vertebrates to develop an acid secreting stomach and as such may make a good comparative model for determining the causative factors behind these differences. We measured gastric pH and temperature continuously during periods of fasting in captive free-swimming nurse sharks (Ginglymostoma cirratum) using autonomous pH/temperature data-loggers. All nurse sharks secreted strong gastric acids (minimum pH 0.4) after feeding; however, for most of the sharks, pH increased to 8.2-8.7, 2-3 days after feeding. Half of the sharks also exhibited periodic oscillations in pH when the stomach was empty that ranged from 1.1 to 8.7 (acid secretion ceased for 11.3 +/- 4.3 h day(-1)). This is in contrast to the gastric pH changes observed from leopard sharks (Triakis semifasciata) in a previous study, where the stomach remains acidic during fasting. The leopard shark is a relatively active, more frequently feeding predator, and continuous acid secretion may increase digestive efficiency. In contrast, the nurse shark is less active and is thought to feed less frequently. Periodic cessation of acid secretion may be an energy conserving mechanism used by animals that feed infrequently and experience extended periods of fasting.

  6. The shark's fin

    International Nuclear Information System (INIS)

    Listinsky, J.L.; Griffiths, H.J.

    1989-01-01

    Initial plain film studies of seven patients with facet fracture-dislocations of the cervical spine were examined retrospectively. Rotation of the cross-table lateral film from a standard vetical viewing orientation to a simulated brow-down position allowed easier appreciation of the dislocated pillar in six of the seven patients. The displaced pillar had an appearance similar to that of the dorsal fin of a shark. We conclude that the finding of a shark's fin appearance of an articular pillar in a traumatized patient warrants further radiographic studies. (author). 8 refs.; 3 figs

  7. Uncertainty representation of grey numbers and grey sets.

    Science.gov (United States)

    Yang, Yingjie; Liu, Sifeng; John, Robert

    2014-09-01

    In the literature, there is a presumption that a grey set and an interval-valued fuzzy set are equivalent. This presumption ignores the existence of discrete components in a grey number. In this paper, new measurements of uncertainties of grey numbers and grey sets, consisting of both absolute and relative uncertainties, are defined to give a comprehensive representation of uncertainties in a grey number and a grey set. Some simple examples are provided to illustrate that the proposed uncertainty measurement can give an effective representation of both absolute and relative uncertainties in a grey number and a grey set. The relationships between grey sets and interval-valued fuzzy sets are also analyzed from the point of view of the proposed uncertainty representation. The analysis demonstrates that grey sets and interval-valued fuzzy sets provide different but overlapping models for uncertainty representation in sets.

  8. GreyGuide. Poster presentation

    OpenAIRE

    Biagioni, Stefania; Farace, Dominic

    2014-01-01

    Welcome to the GreyGuide, a repository of good practices and resources in grey literature. The GreyGuide seeks to capture proposed as well as published practices dealing with the supply and demand sides of grey literature. This is a collaborative project involving GreyNet International and ISTI-CNR. The launch of the GreyGuide Repository took place in December 2013 at the Fifteenth International Conference on Grey Literature. Since then, the acquisition of both proposed and published good pra...

  9. Biased immunoglobulin light chain gene usage in the shark1

    Science.gov (United States)

    Iacoangeli, Anna; Lui, Anita; Naik, Ushma; Ohta, Yuko; Flajnik, Martin; Hsu, Ellen

    2015-01-01

    This study of a large family of kappa light (L) chain clusters in nurse shark completes the characterization of its classical immunoglobulin (Ig) gene content (two heavy chain classes, mu and omega, and four L chain isotopes, kappa, lambda, sigma, and sigma-2). The shark kappa clusters are minigenes consisting of a simple VL-JL-CL array, where V to J recombination occurs over a ~500 bp interval, and functional clusters are widely separated by at least 100 kb. Six out of ca. 39 kappa clusters are pre-rearranged in the germline (GL-joined). Unlike the complex gene organization and multistep assembly process of Ig in mammals, each shark Ig rearrangement, somatic or in the germline, appears to be an independent event localized to the minigene. This study examined the expression of functional, non-productive, and sterile transcripts of the kappa clusters compared to the other three L chain isotypes. Kappa cluster usage was investigated in young sharks, and a skewed pattern of split gene expression was observed, one similar in functional and non-productive rearrangements. These results show that the individual activation of the spatially distant kappa clusters is non-random. Although both split and GL-joined kappa genes are expressed, the latter are prominent in young animals and wane with age. We speculate that, in the shark, the differential activation of the multiple isotypes can be advantageously used in receptor editing. PMID:26342033

  10. Biased Immunoglobulin Light Chain Gene Usage in the Shark.

    Science.gov (United States)

    Iacoangeli, Anna; Lui, Anita; Naik, Ushma; Ohta, Yuko; Flajnik, Martin; Hsu, Ellen

    2015-10-15

    This study of a large family of κ L chain clusters in nurse shark completes the characterization of its classical Ig gene content (two H chain isotypes, μ and ω, and four L chain isotypes, κ, λ, σ, and σ-2). The shark κ clusters are minigenes consisting of a simple VL-JL-CL array, where V to J recombination occurs over an ~500-bp interval, and functional clusters are widely separated by at least 100 kb. Six out of ~39 κ clusters are prerearranged in the germline (germline joined). Unlike the complex gene organization and multistep assembly process of Ig in mammals, each shark Ig rearrangement, somatic or in the germline, appears to be an independent event localized to the minigene. This study examined the expression of functional, nonproductive, and sterile transcripts of the κ clusters compared with the other three L chain isotypes. κ cluster usage was investigated in young sharks, and a skewed pattern of split gene expression was observed, one similar in functional and nonproductive rearrangements. These results show that the individual activation of the spatially distant κ clusters is nonrandom. Although both split and germline-joined κ genes are expressed, the latter are prominent in young animals and wane with age. We speculate that, in the shark, the differential activation of the multiple isotypes can be advantageously used in receptor editing. Copyright © 2015 by The American Association of Immunologists, Inc.

  11. 50 CFR 600.1204 - Shark finning; possession at sea and landing of shark fins.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Shark finning; possession at sea and landing of shark fins. 600.1204 Section 600.1204 Wildlife and Fisheries FISHERY CONSERVATION AND... PROVISIONS Shark Finning § 600.1204 Shark finning; possession at sea and landing of shark fins. (a)(1) No...

  12. Structure and dynamics of the shark assemblage off Recife, Northeastern Brazil.

    Directory of Open Access Journals (Sweden)

    André S Afonso

    Full Text Available Understanding the ecological factors that regulate elasmobranch abundance in nearshore waters is essential to effectively manage coastal ecosystems and promote conservation. However, little is known about elasmobranch populations in the western South Atlantic Ocean. An 8-year, standardized longline and drumline survey conducted in nearshore waters off Recife, northeastern Brazil, allowed us to describe the shark assemblage and to monitor abundance dynamics using zero-inflated generalized additive models. This region is mostly used by several carcharhinids and one ginglymostomid, but sphyrnids are also present. Blacknose sharks, Carcharhinus acronotus, were mostly mature individuals and declined in abundance throughout the survey, contrasting with nurse sharks, Ginglymostoma cirratum, which proliferated possibly due to this species being prohibited from all harvest since 2004 in this region. Tiger sharks, Galeocerdo cuvier, were mostly juveniles smaller than 200 cm and seem to use nearshore waters off Recife between January and September. No long-term trend in tiger shark abundance was discernible. Spatial distribution was similar in true coastal species (i.e. blacknose and nurse sharks whereas tiger sharks were most abundant at the middle continental shelf. The sea surface temperature, tidal amplitude, wind direction, water turbidity, and pluviosity were all selected to predict shark abundance off Recife. Interspecific variability in abundance dynamics across spatiotemporal and environmental gradients suggest that the ecological processes regulating shark abundance are generally independent between species, which could add complexity to multi-species fisheries management frameworks. Yet, further research is warranted to ascertain trends at population levels in the South Atlantic Ocean.

  13. Grey water biodegradability.

    Science.gov (United States)

    Ghunmi, Lina Abu; Zeeman, Grietje; Fayyad, Manar; van Lier, Jules B

    2011-02-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different conditions in the biodegradation test. The maximum aerobic and anaerobic biodegradability and conversion rate for the different COD fractions is determined. The results show that, on average, dormitory grey water COD fractions are 28% suspended, 32% colloidal and 40% dissolved. The studied factors incubation time, inoculum addition and temperature are influencing the determined biodegradability. The maximum biodegradability and biodegradation rate differ between different COD fractions, viz. COD(ss), COD(col) and COD(diss). The dissolved COD fraction is characterised by the lowest degradation rate, both for anaerobic and aerobic conditions. The maximum biodegradability for aerobic and anaerobic conditions is 86 and 70% respectively, whereas the first order conversion rate constant, k₂₀, is 0.119 and 0.005 day⁻¹, respectively. The anaerobic and aerobic conversion rates in relation to temperature can be described by the Arrhenius relation, with temperature coefficients of 1.069 and 1.099, respectively.

  14. Highly migratory shark fisheries research by the National Shark Research Consortium (NSRC), 2002-2007

    OpenAIRE

    Hueter, Robert E.; Cailliet, Gregor M.; Ebert, David A.; Musick, John A.; Burgess, George H.

    2007-01-01

    The National Shark Research Consortium (NSRC) includes the Center for Shark Research at Mote Marine Laboratory, the Pacific Shark Research Center at Moss Landing Marine Laboratories, the Shark Research Program at the Virginia Institute of Marine Science, and the Florida Program for Shark Research at the University of Florida. The consortium objectives include shark-related research in the Gulf of Mexico and along the Atlantic and Pacific coasts of the U.S., education and scientific cooperation.

  15. Large-scale absence of sharks on reefs in the greater-Caribbean: a footprint of human pressures.

    Science.gov (United States)

    Ward-Paige, Christine A; Mora, Camilo; Lotze, Heike K; Pattengill-Semmens, Christy; McClenachan, Loren; Arias-Castro, Ery; Myers, Ransom A

    2010-08-05

    In recent decades, large pelagic and coastal shark populations have declined dramatically with increased fishing; however, the status of sharks in other systems such as coral reefs remains largely unassessed despite a long history of exploitation. Here we explore the contemporary distribution and sighting frequency of sharks on reefs in the greater-Caribbean and assess the possible role of human pressures on observed patterns. We analyzed 76,340 underwater surveys carried out by trained volunteer divers between 1993 and 2008. Surveys were grouped within one km2 cells, which allowed us to determine the contemporary geographical distribution and sighting frequency of sharks. Sighting frequency was calculated as the ratio of surveys with sharks to the total number of surveys in each cell. We compared sighting frequency to the number of people in the cell vicinity and used population viability analyses to assess the effects of exploitation on population trends. Sharks, with the exception of nurse sharks occurred mainly in areas with very low human population or strong fishing regulations and marine conservation. Population viability analysis suggests that exploitation alone could explain the large-scale absence; however, this pattern is likely to be exacerbated by additional anthropogenic stressors, such as pollution and habitat degradation, that also correlate with human population. Human pressures in coastal zones have lead to the broad-scale absence of sharks on reefs in the greater-Caribbean. Preventing further loss of sharks requires urgent management measures to curb fishing mortality and to mitigate other anthropogenic stressors to protect sites where sharks still exist. The fact that sharks still occur in some densely populated areas where strong fishing regulations are in place indicates the possibility of success and encourages the implementation of conservation measures.

  16. Large-scale absence of sharks on reefs in the greater-Caribbean: a footprint of human pressures.

    Directory of Open Access Journals (Sweden)

    Christine A Ward-Paige

    Full Text Available BACKGROUND: In recent decades, large pelagic and coastal shark populations have declined dramatically with increased fishing; however, the status of sharks in other systems such as coral reefs remains largely unassessed despite a long history of exploitation. Here we explore the contemporary distribution and sighting frequency of sharks on reefs in the greater-Caribbean and assess the possible role of human pressures on observed patterns. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed 76,340 underwater surveys carried out by trained volunteer divers between 1993 and 2008. Surveys were grouped within one km2 cells, which allowed us to determine the contemporary geographical distribution and sighting frequency of sharks. Sighting frequency was calculated as the ratio of surveys with sharks to the total number of surveys in each cell. We compared sighting frequency to the number of people in the cell vicinity and used population viability analyses to assess the effects of exploitation on population trends. Sharks, with the exception of nurse sharks occurred mainly in areas with very low human population or strong fishing regulations and marine conservation. Population viability analysis suggests that exploitation alone could explain the large-scale absence; however, this pattern is likely to be exacerbated by additional anthropogenic stressors, such as pollution and habitat degradation, that also correlate with human population. CONCLUSIONS/SIGNIFICANCE: Human pressures in coastal zones have lead to the broad-scale absence of sharks on reefs in the greater-Caribbean. Preventing further loss of sharks requires urgent management measures to curb fishing mortality and to mitigate other anthropogenic stressors to protect sites where sharks still exist. The fact that sharks still occur in some densely populated areas where strong fishing regulations are in place indicates the possibility of success and encourages the implementation of conservation measures.

  17. On two abnormal sharks from Gujarat

    Digital Repository Service at National Institute of Oceanography (India)

    Gopalan, U.K.

    The description of the two abnormal sharks, Carchariaswalbeehmi and Eulamia dussumieri collected from Gujarat, India, is given Of these C walbeehmi was double-headed The other shark E dussumieri had thumb snouted albino...

  18. Grey zones of welfare

    Directory of Open Access Journals (Sweden)

    Ida Harboe Knudsen

    2015-01-01

    Full Text Available In this article I explore the ‘grey zones of welfare’ in rural Lithuania whereby I point to the inherent ambiguities that lies in a system where people to a high degree rely on networks and normative solutions to everyday shortcomings, rather than on the state. I argue that we in the period after socialism witness an increased degree of informal economies and social arrangements, as the formal sector of social security is perceived as unreliable. This results in a model where liberalism and individual ethics co-exist with a strong morality to support the poorest in society.

  19. Shark Conservation: An Educational Approach Based on Children’s Knowledge and Perceptions toward Sharks

    Science.gov (United States)

    Chan, Sau Ying; Lee, Yeung Chung; Ip, Brian Ho Yeung; Cheang, Chi Chiu

    2016-01-01

    Shark conservation has become a focus of current international conservation efforts. However, the misunderstanding of sharks and their negative public portrayal may hinder their conservation. More importantly, the consumption of shark fin, which is very common in Chinese cultures, poses a significant threat to sharks. Hong Kong has long been the world’s largest shark fin trading center. Shark conservation would become more sustainable if public understanding of this predatory fish and an appreciation of its ecological significance could be promoted. It is possible that the demand for fins could be effectively managed through long-term educational efforts targeted at younger generations. To provide essential baseline data for planning of these educational efforts, this project investigated the perceptions of 11 to 12 year-old primary school students in Hong Kong about sharks, and their understanding of ecological concepts and shark-related knowledge. The findings indicate that these students lack sufficient knowledge and possess misconceptions about sharks and their ecological significance in the marine ecosystem. The students’ conceptual understanding level is strongly correlated with their perceptions. Correlational analyses further demonstrated a positive association between formal education and perceptions toward shark conservation. The students who favoured shark fin consumption did so because of its tastiness, whereas concerns about shark population decline and the cruelty of shark hunting were the main reasons for not favoring shark fin consumption. This pilot study provides preliminary but important insights into primary school education regarding the conservation of sharks. PMID:27684706

  20. Shark Conservation: An Educational Approach Based on Children's Knowledge and Perceptions toward Sharks.

    Science.gov (United States)

    Tsoi, Kwok Ho; Chan, Sau Ying; Lee, Yeung Chung; Ip, Brian Ho Yeung; Cheang, Chi Chiu

    Shark conservation has become a focus of current international conservation efforts. However, the misunderstanding of sharks and their negative public portrayal may hinder their conservation. More importantly, the consumption of shark fin, which is very common in Chinese cultures, poses a significant threat to sharks. Hong Kong has long been the world's largest shark fin trading center. Shark conservation would become more sustainable if public understanding of this predatory fish and an appreciation of its ecological significance could be promoted. It is possible that the demand for fins could be effectively managed through long-term educational efforts targeted at younger generations. To provide essential baseline data for planning of these educational efforts, this project investigated the perceptions of 11 to 12 year-old primary school students in Hong Kong about sharks, and their understanding of ecological concepts and shark-related knowledge. The findings indicate that these students lack sufficient knowledge and possess misconceptions about sharks and their ecological significance in the marine ecosystem. The students' conceptual understanding level is strongly correlated with their perceptions. Correlational analyses further demonstrated a positive association between formal education and perceptions toward shark conservation. The students who favoured shark fin consumption did so because of its tastiness, whereas concerns about shark population decline and the cruelty of shark hunting were the main reasons for not favoring shark fin consumption. This pilot study provides preliminary but important insights into primary school education regarding the conservation of sharks.

  1. Characteristics of the shark fisheries of Fiji

    Science.gov (United States)

    Glaus, Kerstin B. J.; Adrian-Kalchhauser, Irene; Burkhardt-Holm, Patricia; White, William T.; Brunnschweiler, Juerg M.

    2015-12-01

    Limited information is available on artisanal and subsistence shark fisheries across the Pacific. The aim of this study was to investigate Fiji’s inshore fisheries which catch sharks. In January and February 2013, 253 semi-directive interviews were conducted in 117 villages and at local harbours on Viti Levu, Vanua Levu, Taveuni, Ovalau and a number of islands of the Mamanuca and Yasawa archipelagos. Of the 253 interviewees, 81.4% reported to presently catch sharks, and 17.4% declared that they did not presently catch any sharks. Of the 206 fishers that reported to catch sharks, 18.4% targeted sharks and 81.6% caught sharks as bycatch. When targeted, primary use of sharks was for consumption or for sale. Sharks caught as bycatch were frequently released (69.6%), consumed (64.9%) or shared amongst the community (26.8%). Fishers’ identification based on an identification poster and DNA barcoding revealed that at least 12 species of elasmobranchs, 11 shark and one ray species (Rhynchobatus australiae) were caught. This study, which is the first focused exploration of the shark catch in Fiji’s inshore fisheries, suggests that the country’s artisanal shark fisheries are small but have the potential to develop into larger and possibly more targeted fisheries.

  2. Characteristics of the shark fisheries of Fiji.

    Science.gov (United States)

    Glaus, Kerstin B J; Adrian-Kalchhauser, Irene; Burkhardt-Holm, Patricia; White, William T; Brunnschweiler, Juerg M

    2015-12-02

    Limited information is available on artisanal and subsistence shark fisheries across the Pacific. The aim of this study was to investigate Fiji's inshore fisheries which catch sharks. In January and February 2013, 253 semi-directive interviews were conducted in 117 villages and at local harbours on Viti Levu, Vanua Levu, Taveuni, Ovalau and a number of islands of the Mamanuca and Yasawa archipelagos. Of the 253 interviewees, 81.4% reported to presently catch sharks, and 17.4% declared that they did not presently catch any sharks. Of the 206 fishers that reported to catch sharks, 18.4% targeted sharks and 81.6% caught sharks as bycatch. When targeted, primary use of sharks was for consumption or for sale. Sharks caught as bycatch were frequently released (69.6%), consumed (64.9%) or shared amongst the community (26.8%). Fishers' identification based on an identification poster and DNA barcoding revealed that at least 12 species of elasmobranchs, 11 shark and one ray species (Rhynchobatus australiae) were caught. This study, which is the first focused exploration of the shark catch in Fiji's inshore fisheries, suggests that the country's artisanal shark fisheries are small but have the potential to develop into larger and possibly more targeted fisheries.

  3. bullwinkle and shark regulate dorsal-appendage morphogenesis in Drosophila oogenesis.

    Science.gov (United States)

    Tran, David H; Berg, Celeste A

    2003-12-01

    bullwinkle (bwk) regulates embryonic anteroposterior patterning and, through a novel germline-to-soma signal, morphogenesis of the eggshell dorsal appendages. We screened for dominant modifiers of the bullwinkle mooseantler eggshell phenotype and identified shark, which encodes an SH2-domain, ankyrin-repeat tyrosine kinase. At the onset of dorsal-appendage formation, shark is expressed in a punctate pattern in the squamous stretch cells overlying the nurse cells. Confocal microscopy with cell-type-specific markers demonstrates that the stretch cells act as a substrate for the migrating dorsal-appendage-forming cells and extend cellular projections towards them. Mosaic analyses reveal that shark is required in follicle cells for cell migration and chorion deposition. Proper shark RNA expression in the stretch cells requires bwk activity, while restoration of shark expression in the stretch cells suppresses the bwk dorsal-appendage phenotype. These results suggest that shark plays an important downstream role in the bwk-signaling pathway. Candidate testing implicates Src42A in a similar role, suggesting conservation with a vertebrate signaling pathway involving non-receptor tyrosine kinases.

  4. Ultrasound examination and behavior scoring of captive broadnose sevengill sharks, Notorynchus cepedianus (Peron, 1807).

    Science.gov (United States)

    Daly, Jonathan; Gunn, Ian; Kirby, Nick; Jones, Robert; Galloway, David

    2007-09-01

    Serial ultrasound examination of four mature female sevengill sharks (Notorynchus cepedianus) was carried out over 18 months. Monitoring the reproductive cycle and development of follicles and fetuses in sharks in a noninvasive manner using this technique has not been reported previously. Sharks were caught out of the "Oceanarium" tank by divers using a specially made catch-out bag, and brought to a holding area for examination. A behavior scoring system was used to monitor the impact of regular handling on the well-being of the animals. Ultrasound showed the growth and regression of follicles in sevengill ovaries, and allowed an approximation of the reproductive stage of these sharks. Monitoring behavior at five time points during the procedure showed that regular handling of sharks for clinical studies could be done with minimal impact on animal welfare. The ability to follow reproductive events in elasmobranches using ultrasonography is an important step in the application of assisted reproductive technology in these species. Assisted reproductive technology, such as monitoring female reproductive cycles and artificial insemination, could potentially be used to maintain genetic diversity and compliment aquaria-based breeding programs for endangered species such as the gray nurse shark (Carcharias taurus). Zoo Biol 26:383-395, 2007. (c) 2007 Wiley-Liss, Inc.

  5. Energy metabolism in mobile, wild-sampled sharks inferred by plasma lipids.

    Science.gov (United States)

    Gallagher, Austin J; Skubel, Rachel A; Pethybridge, Heidi R; Hammerschlag, Neil

    2017-01-01

    Evaluating how predators metabolize energy is increasingly useful for conservation physiology, as it can provide information on their current nutritional condition. However, obtaining metabolic information from mobile marine predators is inherently challenging owing to their relative rarity, cryptic nature and often wide-ranging underwater movements. Here, we investigate aspects of energy metabolism in four free-ranging shark species ( n  = 281; blacktip, bull, nurse, and tiger) by measuring three metabolic parameters [plasma triglycerides (TAG), free fatty acids (FFA) and cholesterol (CHOL)] via non-lethal biopsy sampling. Plasma TAG, FFA and total CHOL concentrations (in millimoles per litre) varied inter-specifically and with season, year, and shark length varied within a species. The TAG were highest in the plasma of less active species (nurse and tiger sharks), whereas FFA were highest among species with relatively high energetic demands (blacktip and bull sharks), and CHOL concentrations were highest in bull sharks. Although temporal patterns in all metabolites were varied among species, there appeared to be peaks in the spring and summer, with ratios of TAG/CHOL (a proxy for condition) in all species displaying a notable peak in summer. These results provide baseline information of energy metabolism in large sharks and are an important step in understanding how the metabolic parameters can be assessed through non-lethal sampling in the future. In particular, this study emphasizes the importance of accounting for intra-specific and temporal variability in sampling designs seeking to monitor the nutritional condition and metabolic responses of shark populations.

  6. Incoherently Coupled Grey-Grey Spatial Soliton Pairs in Biased Two-Photon Photovoltaic Photorefractive Crystals

    International Nuclear Information System (INIS)

    Su Yanli; Jiang Qichang; Ji Xuanmang

    2010-01-01

    The incoherently coupled grey-grey screening-photovoltaic spatial soliton pairs are predicted in biased two-photon photovoltaic photorefractive crystals under steady-state conditions. These grey-grey screening-photovoltaic soliton pairs can be established provided that the incident beams have the same polarization, wavelength, and are mutually incoherent. The grey-grey screening-photovoltaic soliton pairs can be considered as the united form of grey-grey screening soliton pairs and open or closed-circuit grey-grey photovoltaic soliton pairs. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  7. Oceanic sharks clean at coastal seamount.

    Directory of Open Access Journals (Sweden)

    Simon P Oliver

    2011-03-01

    Full Text Available Interactions between pelagic thresher sharks (Alopias pelagicus and cleaner wrasse were investigated at a seamount in the Philippines. Cleaning associations between sharks and teleosts are poorly understood, but the observable interactions seen at this site may explain why these mainly oceanic sharks regularly venture into shallow coastal waters where they are vulnerable to disturbance from human activity. From 1,230 hours of observations recorded by remote video camera between July 2005 and December 2009, 97 cleaner-thresher shark events were analyzed, 19 of which were interrupted. Observations of pelagic thresher sharks interacting with cleaners at the seamount were recorded at all times of day but their frequency declined gradually from morning until evening. Cleaners showed preferences for foraging on specific areas of a thresher shark's body. For all events combined, cleaners were observed to conduct 2,757 inspections, of which 33.9% took place on the shark's pelvis, 23.3% on the pectoral fins, 22.3% on the caudal fin, 8.6% on the body, 8.3% on the head, 2.1% on the dorsal fin, and 1.5% on the gills respectively. Cleaners did not preferentially inspect thresher sharks by time of day or by shark sex, but there was a direct correlation between the amount of time a thresher shark spent at a cleaning station and the number of inspections it received. Thresher shark clients modified their behavior by "circular-stance-swimming," presumably to facilitate cleaner inspections. The cleaner-thresher shark association reflected some of the known behavioral trends in the cleaner-reef teleost system since cleaners appeared to forage selectively on shark clients. Evidence is mounting that in addition to acting as social refuges and foraging grounds for large visiting marine predators, seamounts may also support pelagic ecology by functioning as cleaning stations for oceanic sharks and rays.

  8. Contrasting movements and connectivity of reef-associated sharks using acoustic telemetry: implications for management.

    Science.gov (United States)

    Espinoza, Mario; Lédée, Elodie J I; Simpfendorfer, Colin A; Tobin, Andrew J; Heupel, Michelle R

    2015-12-01

    Understanding the efficacy of marine protected areas (MPAs) for wide-ranging predators is essential to designing effective management and conservation approaches. The use of acoustic monitoring and network analysis can improve our understanding of the spatial ecology and functional connectivity of reef-associated species, providing a useful approach for reef-based conservation planning. This study compared and contrasted the movement and connectivity of sharks with different degrees of reef association. We examined the residency, dispersal, degree of reef connectivity, and MPA use of grey reef (Carcharhinus amblyrhynchos), silvertip (C. albimarginatus), and bull (C. leucas) sharks monitored in the central Great Barrier Reef (GBR). An array of 56 acoustic receivers was used to monitor shark movements on 17 semi-isolated reefs. Carcharhinus amblyrhynchos and C. albimarginatus were detected most days at or near their tagging reef. However, while C. amblyrhynchos spent 80% of monitoring days in the array, C. albimarginatus was only detected 50% of the time. Despite both species moving similar distances (sharks like C. leucas, a combination of spatial planning and other alternative measures is critical. Our findings demonstrate that acoustic monitoring can serve as a useful platform for designing more effective MPA networks for reef predators displaying a range of movement patterns.

  9. Cyanobacterial Neurotoxin BMAA and Mercury in Sharks

    Directory of Open Access Journals (Sweden)

    Neil Hammerschlag

    2016-08-01

    Full Text Available Sharks have greater risk for bioaccumulation of marine toxins and mercury (Hg, because they are long-lived predators. Shark fins and cartilage also contain β-N-methylamino-l-alanine (BMAA, a ubiquitous cyanobacterial toxin linked to neurodegenerative diseases. Today, a significant number of shark species have found their way onto the International Union for Conservation of Nature (IUCN Red List of Threatened Species. Many species of large sharks are threatened with extinction due in part to the growing high demand for shark fin soup and, to a lesser extent, for shark meat and cartilage products. Recent studies suggest that the consumption of shark parts may be a route to human exposure of marine toxins. Here, we investigated BMAA and Hg concentrations in fins and muscles sampled in ten species of sharks from the South Atlantic and Pacific Oceans. BMAA was detected in all shark species with only seven of the 55 samples analyzed testing below the limit of detection of the assay. Hg concentrations measured in fins and muscle samples from the 10 species ranged from 0.05 to 13.23 ng/mg. These analytical test results suggest restricting human consumption of shark meat and fins due to the high frequency and co-occurrence of two synergistic environmental neurotoxic compounds.

  10. Cyanobacterial Neurotoxin BMAA and Mercury in Sharks.

    Science.gov (United States)

    Hammerschlag, Neil; Davis, David A; Mondo, Kiyo; Seely, Matthew S; Murch, Susan J; Glover, William Broc; Divoll, Timothy; Evers, David C; Mash, Deborah C

    2016-08-16

    Sharks have greater risk for bioaccumulation of marine toxins and mercury (Hg), because they are long-lived predators. Shark fins and cartilage also contain β-N-methylamino-l-alanine (BMAA), a ubiquitous cyanobacterial toxin linked to neurodegenerative diseases. Today, a significant number of shark species have found their way onto the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. Many species of large sharks are threatened with extinction due in part to the growing high demand for shark fin soup and, to a lesser extent, for shark meat and cartilage products. Recent studies suggest that the consumption of shark parts may be a route to human exposure of marine toxins. Here, we investigated BMAA and Hg concentrations in fins and muscles sampled in ten species of sharks from the South Atlantic and Pacific Oceans. BMAA was detected in all shark species with only seven of the 55 samples analyzed testing below the limit of detection of the assay. Hg concentrations measured in fins and muscle samples from the 10 species ranged from 0.05 to 13.23 ng/mg. These analytical test results suggest restricting human consumption of shark meat and fins due to the high frequency and co-occurrence of two synergistic environmental neurotoxic compounds.

  11. HMSRP Hawaiian Monk Seal Shark Predation Mitigation Shark Sightings and Incidents

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data on direct sightings of large sharks around monk seal pupping sites and shark incidents on preweaned and newly weaned pups at French Frigate Shoals are entered...

  12. Shark fishing effort and catch of the ragged-tooth shark Carcharias ...

    African Journals Online (AJOL)

    An integrated telephone and on-site questionnaire survey was used to estimate total shark fishing effort and specific catch of the ragged-tooth shark Carcharias taurus by coastal club-affiliated shore-anglers, primarily along the east coast of South Africa. Mean total shark fishing effort was estimated to be 37 820 fisherdays ...

  13. Sharks and people: insight into the global practices of tourism operators and their attitudes to shark behaviour.

    Science.gov (United States)

    Richards, Kirsty; O'Leary, Bethan C; Roberts, Callum M; Ormond, Rupert; Gore, Mauvis; Hawkins, Julie P

    2015-02-15

    Shark tourism is a popular but controversial activity. We obtained insights into this industry via a global e-mailed questionnaire completed by 45 diving/snorkelling operators who advertised shark experiences (shark operators) and 49 who did not (non-shark operators). 42% of shark operators used an attractant to lure sharks and 93% stated they had a formal code of conduct which 86% enforced "very strictly". While sharks were reported to normally ignore people, 9 operators had experienced troublesome behaviour from them. Whilst our research corroborates previous studies indicating minimal risk to humans from most shark encounters, a precautionary approach to provisioning is required to avoid potential ecological and societal effects of shark tourism. Codes of conduct should always stipulate acceptable diver behaviour and appropriate diver numbers and shark operators should have a moral responsibility to educate their customers about the need for shark conservation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. GreyGuide Forum and Repository

    OpenAIRE

    Biagioni, Stefania; Farace, Dominic

    2014-01-01

    We present the GreyGuide: an online forum and repository of good practice in the field of grey literature. The launch of the GreyGuide Repository took place in December 2013 at the Fifteenth International Conference on Grey Literature. Since then, the acquisition of both proposed and published good practices are underway. The GreyGuide as an online forum is currently in a developmental stage and is influenced by the changes that have taken place in GreyNet's new infrastructure commencing in J...

  15. Pelagic shark fisheries of Indonesia's Eastern Indian Ocean ...

    African Journals Online (AJOL)

    Sharks are commonly caught in Indonesian waters both by target fisheries and as bycatch. Fishers targeting sharks mostly employ drift longlines, whereas tuna longlines and gillnets are the gear mostly responsible for shark bycatch. Our studies on shark fisheries have been conducted since 2006 and have focused on the ...

  16. GreyGuide, GreyNet’s web access portal and lobby for change in Grey Literature

    OpenAIRE

    Farace, Dominic J. (GreyNet); Frantzen, Jerry (GreyNet); Biagioni, Stefania (ISTI-CNR); Carlesi, Carlo (ISTI-CNR); Ponti, Roberto (ISTI-CNR); Stock, Christiane (Inist-CNRS); GreyNet, Grey Literature Network Service

    2015-01-01

    In December 2013, the GreyGuide was formerly launched as an online forum and repository of good practice in grey literature. The project partners then turned to the acquisition of both proposed and published good practices. During this same timeframe, GreyNet – one of the project partners – welcomed far reaching developments in its infrastructure. Three new committees were established alongside its Program Committee in line with GreyNet’s fourfold mission dedicated to research, publication, o...

  17. Correlations of metabolic rate and body acceleration in three species of coastal sharks under contrasting temperature regimes.

    Science.gov (United States)

    Lear, Karissa O; Whitney, Nicholas M; Brewster, Lauran R; Morris, Jack J; Hueter, Robert E; Gleiss, Adrian C

    2017-02-01

    The ability to produce estimates of the metabolic rate of free-ranging animals is fundamental to the study of their ecology. However, measuring the energy expenditure of animals in the field has proved difficult, especially for aquatic taxa. Accelerometry presents a means of translating metabolic rates measured in the laboratory to individuals studied in the field, pending appropriate laboratory calibrations. Such calibrations have only been performed on a few fish species to date, and only one where the effects of temperature were accounted for. Here, we present calibrations between activity, measured as overall dynamic body acceleration (ODBA), and metabolic rate, measured through respirometry, for nurse sharks (Ginglymostoma cirratum), lemon sharks (Negaprion brevirostris) and blacktip sharks (Carcharhinus limbatus). Calibrations were made at a range of volitional swimming speeds and experimental temperatures. Linear mixed models were used to determine a predictive equation for metabolic rate based on measured ODBA values, with the optimal model using ODBA in combination with activity state and temperature to predict metabolic rate in lemon and nurse sharks, and ODBA and temperature to predict metabolic rate in blacktip sharks. This study lays the groundwork for calculating the metabolic rate of these species in the wild using acceleration data. © 2017. Published by The Company of Biologists Ltd.

  18. Calcitonin produces hypercalcemia in leopard sharks.

    Science.gov (United States)

    Glowacki, J; O'Sullivan, J; Miller, M; Wilkie, D W; Deftos, L J

    1985-02-01

    Calcitonin was detected by RIA in sera from four marine species, leopard sharks (Triakis semifasciata), horn sharks (Heterodontus francisci), thornback rays (Platyrhinoides triseriata), and kelp bass (Paralabrax clathratus). These animals have levels of calcitonin and calcium higher than freshwater and terrestrial species have. The administration of salmon calcitonin to bass (4 micrograms/kg BW) produced hypocalcemia and hypophosphatemia as has been reported for other bony vertebrates. In marked contrast, calcitonin produced a prompt hypercalcemia in sharks; the average was 9.8% increase in serum calcium in nine animals with no attendant change in phosphorus. These findings demonstrate that calcitonin can increase serum calcium in sharks. Because shark skeleton is composed of cartilage, this hypercalcemic effect of calcitonin does not require a bony skeleton.

  19. Overview. Rethinking the grey literature's definition

    International Nuclear Information System (INIS)

    Ikeda, Kiyoshi

    2012-01-01

    Grey literature said to do difficult to obtain through commercial publishers. Recently, according to the spread of institutional repositories, grey literature is published on the Web and its full text is open to the public, then it has become easily accessible. Yet, the accessibility of grey literature has not been fully resolved. In this paper, the author introduces the definition of grey literature based on the discussion of the International Conference on Grey Literature (International Conference on Grey literature) and tries to reorganize and discuss on issues concerning the problems of grey literature accessibility. The author indicates that there are still many challenges in this field, also indicates that stable access to the sources on the Web is not always guaranteed. It is concluded that expertises and experiences of a librarian should be leveraged to get solutions regarding the accessibility of grey literature. (author)

  20. Black and grey neutron detectors

    International Nuclear Information System (INIS)

    Gabbard, F.

    1977-01-01

    Recent progress in the development and use of ''black'' and ''grey'' detectors is reviewed. Such detectors are widely used for counting neutrons in (p,n) and (α,n) experiments and in neutron cross section measurements. Accuracy of each detector is stressed. 19 figures

  1. Grey Literature and the Internet

    Science.gov (United States)

    Hartman, Karen A.

    2006-01-01

    Accreditation standards for professional schools offering social work degrees mandate curriculum content that provides students with skills to analyze, formulate, and influence social policies. An important source of analytical thinking about social policy is the "grey" literature issued by public policy organizations, think tanks,…

  2. Land governance as grey zone

    DEFF Research Database (Denmark)

    Kjær, Anne Mette

    2017-01-01

    demonstrates that in Uganda, the need to maintain the ruling coalition in a clientelist political settlement to build electoral support, and the desire to attract economic investors, constitute political incentives to maintain land governance as a grey zone, even if there is apparent political...

  3. How Close is too Close? The Effect of a Non-Lethal Electric Shark Deterrent on White Shark Behaviour

    OpenAIRE

    Kempster, Ryan M.; Egeberg, Channing A.; Hart, Nathan S.; Ryan, Laura; Chapuis, Lucille; Kerr, Caroline C.; Schmidt, Carl; Huveneers, Charlie; Gennari, Enrico; Yopak, Kara E.; Meeuwig, Jessica J.; Collin, Shaun P.

    2016-01-01

    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 scienti...

  4. Grey water treatment systems: A review

    NARCIS (Netherlands)

    Abu-Ghunmi, L.N.A.H.; Zeeman, G.; Fayyad, M.; Lier, van J.B.

    2011-01-01

    This review aims to discern a treatment for grey water by examining grey water characteristics, reuse standards, technology performance and costs. The review reveals that the systems for treating grey water, whatever its quality, should consist of processes that are able to trap pollutants with a

  5. Grey Guide Repository: presentation and demo

    OpenAIRE

    Biagioni, Stefania; Carlesi, Carlo; Schopfel, Joachim; Farace, Dominic; Frantzen, Jerry

    2013-01-01

    The goal of this project is to develop an open source repository of good practices in the field of grey literature. That which originated in monographic form will now open and expand to include content from the global grey literature community. Such practices will range from the production and processing of grey literature through to its distribution, uses, and preservation.

  6. Grey Guide: A Community Driven Open Resource Project in Grey Literature

    OpenAIRE

    Biagioni, Stefania; Giannini, Silvia

    2017-01-01

    In December 2013, the GreyGuide Project was formerly launched as an online forum and repository of good practice in grey literature. The GreyGuide manages Open Source Repositories and provides a unique resource in the field of grey literature that is long awaited and which responds to the information needs of a diverse, international grey literature community. As GreyNet's web access Portal, the GreyGuide now provides a wealth of content that was previously either confined to web pages or was...

  7. Grey Language Hesitant Fuzzy Group Decision Making Method Based on Kernel and Grey Scale.

    Science.gov (United States)

    Li, Qingsheng; Diao, Yuzhu; Gong, Zaiwu; Hu, Aqin

    2018-03-02

    Based on grey language multi-attribute group decision making, a kernel and grey scale scoring function is put forward according to the definition of grey language and the meaning of the kernel and grey scale. The function introduces grey scale into the decision-making method to avoid information distortion. This method is applied to the grey language hesitant fuzzy group decision making, and the grey correlation degree is used to sort the schemes. The effectiveness and practicability of the decision-making method are further verified by the industry chain sustainable development ability evaluation example of a circular economy. Moreover, its simplicity and feasibility are verified by comparing it with the traditional grey language decision-making method and the grey language hesitant fuzzy weighted arithmetic averaging (GLHWAA) operator integration method after determining the index weight based on the grey correlation.

  8. Shark Spotters: Successfully reducing spatial overlap between white sharks (Carcharodon carcharias) and recreational water users in False Bay, South Africa.

    Science.gov (United States)

    Engelbrecht, Tamlyn; Kock, Alison; Waries, Sarah; O'Riain, M Justin

    2017-01-01

    White sharks (Carcharodon carcharias) are apex predators that play an important role in the structure and stability of marine ecosystems. Despite their ecological importance and protected status, white sharks are still subject to lethal control to reduce the risk of shark bites for recreational water users. The Shark Spotters program, pioneered in Cape Town, South Africa, provides a non-lethal alternative for reducing the risk of human-shark conflict. In this study we assessed the efficacy of the Shark Spotters program in reducing overlap between water users and white sharks at two popular beaches in False Bay, South Africa. We investigated seasonal and diel patterns in water use and shark presence at each beach, and thereafter quantified the impact of different shark warnings from shark spotters on water user abundance. We also assessed the impact of a fatal shark incident on patterns of water use. Our results revealed striking diel and seasonal overlap between white sharks and water users at both beaches. Despite this, there was a low rate of shark-human incidents (0.5/annum) which we attribute partly to the success of the Shark Spotters program. Shark spotters use visual (coloured flags) and auditory (siren) cues to inform water users of risk associated with white shark presence in the surf zone. Our results showed that the highest risk category (denoted by a white flag and accompanying siren) caused a significant reduction in water user abundance; however the secondary risk category (denoted by a red flag with no siren) had no significant effect on water users. A fatal shark incident was shown to negatively impact the number of water users present for at least three months following the incident. Our results indicate that the Shark Spotters program effectively reduces spatial overlap between white sharks and water users when the risk of conflict is highest.

  9. The Ecological Role of Sharks on Coral Reefs.

    Science.gov (United States)

    Roff, George; Doropoulos, Christopher; Rogers, Alice; Bozec, Yves-Marie; Krueck, Nils C; Aurellado, Eleanor; Priest, Mark; Birrell, Chico; Mumby, Peter J

    2016-05-01

    Sharks are considered the apex predator of coral reefs, but the consequences of their global depletion are uncertain. Here we explore the ecological roles of sharks on coral reefs and, conversely, the importance of reefs for sharks. We find that most reef-associated shark species do not act as apex predators but instead function as mesopredators along with a diverse group of reef fish. While sharks perform important direct and indirect ecological roles, the evidence to support hypothesised shark-driven trophic cascades that benefit corals is weak and equivocal. Coral reefs provide some functional benefits to sharks, but sharks do not appear to favour healthier reef environments. Restoring populations of sharks is important and can yet deliver ecological surprise. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. The Effect of Background Music in Shark Documentaries on Viewers' Perceptions of Sharks.

    Directory of Open Access Journals (Sweden)

    Andrew P Nosal

    Full Text Available Despite the ongoing need for shark conservation and management, prevailing negative sentiments marginalize these animals and legitimize permissive exploitation. These negative attitudes arise from an instinctive, yet exaggerated fear, which is validated and reinforced by disproportionate and sensationalistic news coverage of shark 'attacks' and by highlighting shark-on-human violence in popular movies and documentaries. In this study, we investigate another subtler, yet powerful factor that contributes to this fear: the ominous background music that often accompanies shark footage in documentaries. Using three experiments, we show that participants rated sharks more negatively and less positively after viewing a 60-second video clip of swimming sharks set to ominous background music, compared to participants who watched the same video clip set to uplifting background music, or silence. This finding was not an artifact of soundtrack alone because attitudes toward sharks did not differ among participants assigned to audio-only control treatments. This is the first study to demonstrate empirically that the connotative attributes of background music accompanying shark footage affect viewers' attitudes toward sharks. Given that nature documentaries are often regarded as objective and authoritative sources of information, it is critical that documentary filmmakers and viewers are aware of how the soundtrack can affect the interpretation of the educational content.

  11. The Effect of Background Music in Shark Documentaries on Viewers' Perceptions of Sharks.

    Science.gov (United States)

    Nosal, Andrew P; Keenan, Elizabeth A; Hastings, Philip A; Gneezy, Ayelet

    2016-01-01

    Despite the ongoing need for shark conservation and management, prevailing negative sentiments marginalize these animals and legitimize permissive exploitation. These negative attitudes arise from an instinctive, yet exaggerated fear, which is validated and reinforced by disproportionate and sensationalistic news coverage of shark 'attacks' and by highlighting shark-on-human violence in popular movies and documentaries. In this study, we investigate another subtler, yet powerful factor that contributes to this fear: the ominous background music that often accompanies shark footage in documentaries. Using three experiments, we show that participants rated sharks more negatively and less positively after viewing a 60-second video clip of swimming sharks set to ominous background music, compared to participants who watched the same video clip set to uplifting background music, or silence. This finding was not an artifact of soundtrack alone because attitudes toward sharks did not differ among participants assigned to audio-only control treatments. This is the first study to demonstrate empirically that the connotative attributes of background music accompanying shark footage affect viewers' attitudes toward sharks. Given that nature documentaries are often regarded as objective and authoritative sources of information, it is critical that documentary filmmakers and viewers are aware of how the soundtrack can affect the interpretation of the educational content.

  12. Regional movements of the tiger shark, Galeocerdo cuvier, off Northeastern Brazil: inferences regarding shark attack hazard.

    Science.gov (United States)

    Hazin, Fábio H V; Afonso, André S; De Castilho, Pedro C; Ferreira, Luciana C; Rocha, Bruno C L M

    2013-09-01

    An abnormally high shark attack rate verified off Recife could be related to migratory behavior of tiger sharks. This situation started after the construction of the Suape port to the south of Recife. A previous study suggested that attacking sharks could be following northward currents and that they were being attracted shoreward by approaching vessels. In this scenario, such northward movement pattern could imply a higher probability of sharks accessing the littoral area of Recife after leaving Suape. Pop-up satellite archival tags were deployed on five tiger sharks caught off Recife to assess their movement patterns off northeastern Brazil. All tags transmitted from northward latitudes after 7-74 days of freedom. The shorter, soak distance between deployment and pop-up locations ranged between 33-209 km and implied minimum average speeds of 0.02-0.98 km.h-1. Both pop-up locations and depth data suggest that tiger shark movements were conducted mostly over the continental shelf. The smaller sharks moved to deeper waters within 24 hours after releasing, but they assumed a shallower (shark movements in the South Atlantic, this study also adds new information for the reasoning of the high shark attack rate verified in this region.

  13. Relative abundance and size of coastal sharks derived from commercial shark longline catch and effort data.

    Science.gov (United States)

    Carlson, J K; Hale, L F; Morgan, A; Burgess, G

    2012-04-01

    In the north-west Atlantic Ocean, stock assessments conducted for some commercially harvested coastal sharks indicate declines from 64 to 80% with respect to virgin population levels. While the status of commercially important species is available, abundance trend information for other coastal shark species in the north-west Atlantic Ocean are unavailable. Using a generalized linear modelling (GLM) approach, a relative abundance index was derived from 1994 to 2009 using observer data collected in a commercial bottom longline fishery. Trends in abundance and average size were estimated for bull shark Carcharhinus leucas, spinner shark Carcharhinus brevipinna, tiger shark Galeocerdo cuvier and lemon shark Negaprion brevirostris. Increases in relative abundance for all shark species ranged from 14% for C. brevipinna, 12% for C. leucas, 6% for N. brevirostris and 3% for G. cuvier. There was no significant change in the size at capture over the time period considered for all species. While the status of shark populations should not be based exclusively on abundance trend information, but ultimately on stock assessment models, results from this study provide some cause for optimism on the status of these coastal shark species. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

  14. Characterization of shark complement factor I gene(s): genomic analysis of a novel shark-specific sequence.

    Science.gov (United States)

    Shin, Dong-Ho; Webb, Barbara M; Nakao, Miki; Smith, Sylvia L

    2009-07-01

    Complement factor I is a crucial regulator of mammalian complement activity. Very little is known of complement regulators in non-mammalian species. We isolated and sequenced four highly similar complement factor I cDNAs from the liver of the nurse shark (Ginglymostoma cirratum), designated as GcIf-1, GcIf-2, GcIf-3 and GcIf-4 (previously referred to as nsFI-a, -b, -c and -d) which encode 689, 673, 673 and 657 amino acid residues, respectively. They share 95% (shark-specific sequence between the leader peptide (LP) and the factor I membrane attack complex (FIMAC) domain. The cDNA sequences differ only in the size and composition of the shark-specific region (SSR). Sequence analysis of each SSR has identified within the region two novel short sequences (SS1 and SS2) and three repeat sequences (RS1-3). Genomic analysis has revealed the existence of three introns between the leader peptide and the FIMAC domain, tentatively designated intron 1, intron 2, and intron 3 which span 4067, 2293 and 2082bp, respectively. Southern blot analysis suggests the presence of a single gene copy for each cDNA type. Phylogenetic analysis suggests that complement factor I of cartilaginous fish diverged prior to the emergence of mammals. All four GcIf cDNA species are expressed in four different tissues and the liver is the main tissue in which expression level of all four is high. This suggests that the expression of GcIf isotypes is tissue-dependent.

  15. Shark class II invariant chain reveals ancient conserved relationships with cathepsins and MHC class II.

    Science.gov (United States)

    Criscitiello, Michael F; Ohta, Yuko; Graham, Matthew D; Eubanks, Jeannine O; Chen, Patricia L; Flajnik, Martin F

    2012-03-01

    The invariant chain (Ii) is the critical third chain required for the MHC class II heterodimer to be properly guided through the cell, loaded with peptide, and expressed on the surface of antigen presenting cells. Here, we report the isolation of the nurse shark Ii gene, and the comparative analysis of Ii splice variants, expression, genomic organization, predicted structure, and function throughout vertebrate evolution. Alternative splicing to yield Ii with and without the putative protease-protective, thyroglobulin-like domain is as ancient as the MHC-based adaptive immune system, as our analyses in shark and lizard further show conservation of this mechanism in all vertebrate classes except bony fish. Remarkable coordinate expression of Ii and class II was found in shark tissues. Conserved Ii residues and cathepsin L orthologs suggest their long co-evolution in the antigen presentation pathway, and genomic analyses suggest 450 million years of conserved Ii exon/intron structure. Other than an extended linker preceding the thyroglobulin-like domain in cartilaginous fish, the Ii gene and protein are predicted to have largely similar physiology from shark to man. Duplicated Ii genes found only in teleosts appear to have become sub-functionalized, as one form is predicted to play the same role as that mediated by Ii mRNA alternative splicing in all other vertebrate classes. No Ii homologs or potential ancestors of any of the functional Ii domains were found in the jawless fish or lower chordates. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Coupling effects of grey-grey separate spatial screening soliton pairs

    International Nuclear Information System (INIS)

    Jiang Qichang; Su Yanli; Ji Xuanmang

    2012-01-01

    The existence and coupling effects of grey-grey separate spatial soliton pairs in a biased series non-photovoltaic photorefractive crystal circuit are investigated in this paper. The numerical solution of grey-grey soliton pairs is derived. The coupling effects between two grey solitons resulting from the input optical intensity and crystal temperature are analyzed numerically. The results show that when the input optical intensity of one crystal changes, two grey solitons in a soliton pair will all change; that is, two grey solitons can affect each other by the light-induced current that flows from one crystal to another. When the temperature of one crystal increases, the intensity width of the grey soliton in this crystal first decreases and then increases. Simultaneously, the intensity width of another grey soliton increases monotonically.

  17. Population trends in Pacific Oceanic sharks and the utility of regulations on shark finning.

    Science.gov (United States)

    Clarke, Shelley C; Harley, Shelton J; Hoyle, Simon D; Rice, Joel S

    2013-02-01

    Accurate assessment of shark population status is essential for conservation but is often constrained by limited and unreliable data. To provide a basis for improved management of shark resources, we analyzed a long-term record of species-specific catches, sizes, and sexes of sharks collected by onboard observers in the western and central Pacific Ocean from 1995 to 2010. Using generalized linear models, we estimated population-status indicators on the basis of catch rate and biological indicators of fishing pressure on the basis of median size to identify trends for blue (Prionace glauca), mako (Isurus spp.), oceanic whitetip (Carcharhinus longimanus), and silky (Carcharhinus falciformis) sharks. Standardized catch rates of longline fleets declined significantly for blue sharks in the North Pacific (by 5% per year [CI 2% to 8%]), for mako sharks in the North Pacific (by 7% per year [CI 3% to 11%]), and for oceanic whitetip sharks in tropical waters (by 17% per year [CI 14% to 20%]). Median lengths of silky and oceanic whitetip sharks decreased significantly in their core habitat, and almost all sampled silky sharks were immature. Our results are consistent with results of analyses of similar data sets. Combined, these results and evidence of targeted fishing for sharks in some regional fisheries heighten concerns for sustainable utilization, particularly for oceanic whitetip and North Pacific blue sharks. Regional regulations that prohibit shark finning (removal of fins and discarding of the carcass) were enacted in 2007 and are in many cases the only form of control on shark catches. However, there is little evidence of a reduction of finning in longline fisheries. In addition, silky and oceanic whitetip sharks are more frequently retained than finned, which suggests that even full implementation of and adherence to a finning prohibition may not substantially reduce mortality rates for these species. We argue that finning prohibitions divert attention from

  18. IgM-mediated opsonization and cytotoxicity in the shark.

    Science.gov (United States)

    McKinney, E C; Flajnik, M F

    1997-02-01

    Two types of cytotoxic reactions have been observed using cells from the nurse shark: spontaneous cytotoxicity mediated by cells of the macrophage lineage and antibody-dependent killing carried out by a different effector cell population. Previous data showed that removal of phagocytic cells using iron particles abolished macrophage-mediated killing, but not antibody-dependent reactions. The current study used single cell assays and showed that the effector of antibody-driven reactions was the neutrophil. Surprisingly, the mechanism of killing was shown to be phagocytosis mediated by both 7S and 19S immunoglobulin M (IgM). Reactions proceeded with as little as 0.01 microg of purified 19S or 7S IgM and were complete within 4-6 h. In contrast, purified immunoglobulin did not adsorb to macrophages and had no effect on target cell binding or cytotoxicity. Pretreatment of cells with cytochalasin D abolished the phagocytic reaction, but not spontaneous cytotoxicity. These data show that antibody-mediated killing results from opsonization and phagocytosis; the mechanism of macrophage killing is currently unknown. In addition, these data show that the shark neutrophil, not the macrophage lineage, carries a receptor for Fc mu.

  19. Methylmercury in dried shark fins and shark fin soup from American restaurants.

    Science.gov (United States)

    Nalluri, Deepthi; Baumann, Zofia; Abercrombie, Debra L; Chapman, Demian D; Hammerschmidt, Chad R; Fisher, Nicholas S

    2014-10-15

    Consumption of meat from large predatory sharks exposes human consumers to high levels of toxic monomethylmercury (MMHg). There also have been claims that shark fins, and hence the Asian delicacy shark fin soup, contain harmful levels of neurotoxic chemicals in combination with MMHg, although concentrations of MMHg in shark fins are unknown. We measured MMHg in dried, unprocessed fins (n=50) of 13 shark species that occur in the international trade of dried shark fins as well as 50 samples of shark fin soup prepared by restaurants from around the United States. Concentrations of MMHg in fins ranged from 9 to 1720 ng/g dry wt. MMHg in shark fin soup ranged from sharks such as hammerheads (Sphyrna spp.). Consumption of a 240 mL bowl of shark fin soup containing the average concentration of MMHg (4.6 ng/mL) would result in a dose of 1.1 μg MMHg, which is 16% of the U.S. EPA's reference dose (0.1 μg MMHg per 1 kg per day in adults) of 7.4 μg per day for a 74 kg person. If consumed, the soup containing the highest measured MMHg concentration would exceed the reference dose by 17%. While shark fin soup represents a potentially important source of MMHg to human consumers, other seafood products, particularly the flesh of apex marine predators, contain much higher MMHg concentrations and can result in substantially greater exposures of this contaminant for people. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Size of the great white shark (carcharodon).

    Science.gov (United States)

    Randall, J E

    1973-07-13

    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 sharks as long as 25 or 26 feet (7 (1/2) or 8 meters) exist today. The size of extinct Carcharodon has also been grossly exaggerated. Based on a projection of a curve of tooth size of Recent Carcharodon carcharias, the largest fossil Carcharodon were about 43 feet ( approximately 13 meters) long.

  1. Atlantic Sharpnose Shark Reproductive Biology Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reproductive data from Atlantic sharpnose sharks were collected from specimens captured throughout the northern Gulf of Mexico on various research vessels. Data...

  2. Cooperative Shark Mark Recapture Database (MRDBS)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Shark Mark Recapture Database is a Cooperative Research Program database system used to keep multispecies mark-recapture information in a common format for...

  3. Preferred conservation policies of shark researchers.

    Science.gov (United States)

    Shiffman, David S; Hammerschlag, Neil

    2016-08-01

    There is increasing concern about the conservation status of sharks. However, the presence of numerous different (and potentially mutually exclusive) policies complicates management implementation and public understanding of the process. We distributed an online survey to members of the largest professional shark and ray research societies to assess member knowledge of and attitudes toward different conservation policies. Questions covered society member opinions on conservation and management policies, personal histories of involvement in advocacy and management, and perceptions of the approach of conservation nongovernmental organizations (NGOs) to shark conservation. One hundred and two surveys were completed (overall response rate 21%). Respondents considered themselves knowledgeable about and actively involved in conservation and management policy; a majority believed scientists have a responsibility to advocate for conservation (75%), and majorities have sent formal public comments to policymakers (54%) and included policy suggestions in their papers (53%). They believe sustainable shark fisheries are possible, are currently happening today (in a few places), and should be the goal instead of banning fisheries. Respondents were generally less supportive of newer limit-based (i.e., policies that ban exploitation entirely without a species-specific focus) conservation policy tools, such as shark sanctuaries and bans on the sale of shark fins, than of target-based fisheries management tools (i.e., policies that allow for sustainable harvest of species whose populations can withstand it), such as fishing quotas. Respondents were generally supportive of environmental NGO efforts to conserve sharks but raised concerns about some NGOs that they perceived as using incorrect information and focusing on the wrong problems. Our results show there is an ongoing debate in shark conservation and management circles relative to environmental policy on target-based natural

  4. An FMEA analysis using grey theory and grey rough sets

    Directory of Open Access Journals (Sweden)

    Farshad Faezy Razi

    2013-10-01

    Full Text Available This paper presents a hybrid method for detecting the most important failure items as well as the most effective alternative strategy to cope with possible events. The proposed model of this paper uses grey technique to rank various alternatives and FMEA technique to find important faults. The implementation of the proposed method has been illustrated for an existing example on the literature. The results of this method show that the proposed model has been capable of detecting the most trouble making problems with fuzzy logic and finds the most important solution strategy using FMEA technique.

  5. Shark predation on Indian Ocean bottlenose dolphins TUTSiops ...

    African Journals Online (AJOL)

    1988-10-24

    Oct 24, 1988 ... Four species of shark, the Zambesi (Carcharhinus leucas), the tiger (Galeocerdo ... level of shark predation on bottlenose dolphins was unknown it appeared to ..... possible examples of these adaptations. Acknowledgments.

  6. Grey water reclamation by decentralized MBR prototype

    OpenAIRE

    Santasmasas Rubiralta, Carme; Rovira Boixaderas, Miquel; Clarens Blanco, Frederic; Valderrama Angel, César Alberto

    2013-01-01

    Grey water treatment and reuse for non-drinking water requirements has become of great interest in arid and semi-arid zones where water resources are becoming both quantitatively and qualitatively scarce. In this study a decentralized and automatic MBR prototype has been designed and installed in the REMOSA facilities for treatment of low-load grey water to be recycled in flushing-toilet application. The recycling treatment of grey water comprises four stages: screening, biological oxidation,...

  7. The luminous and the grey

    CERN Document Server

    Batchelor, David

    2014-01-01

    Color surrounds us: the lush green hues of trees and grasses, the variant blues of water and the sky, the bright pops of yellow and red from flowers. But at the same time, color lies at the limits of language and understanding. In this absorbing sequel to Chromophobia-which addresses the extremes of love and loathing provoked by color since antiquity-David Batchelor charts color's more ambiguous terrain.   The Luminous and the Grey explores the places where color comes into being and where it fades away, probing when it begins and when it ends both in the imagination and in the material world.

  8. "Shark is the man!": ethnoknowledge of Brazil's South Bahia fishermen regarding shark behaviors.

    Science.gov (United States)

    Barbosa-Filho, Márcio Luiz Vargas; Schiavetti, Alexandre; Alarcon, Daniela Trigueirinho; Costa-Neto, Eraldo Medeiros

    2014-07-03

    Fishermen's knowledge is a source of indispensable information in decision-making processes related to efforts to stimulate the management and conservation of fishing resources, especially in developing countries. This study analyzed the knowledge of fishermen from three municipal areas of Bahia in northeast Brazil regarding the behavior repertoire of sharks and the possible influence that these perceptions may have on the inclination to preserve these animals. This is a pioneering study on the ethnobiological aspects of elasmobranchs in Brazil. Open, semi-structured interviews with shark fishing specialists were conducted between September 2011 and October 2012. The interviews addressed the fishermen's profile, fishing techniques and knowledge about sharks, focusing on the behaviours exhibited by sharks. The data were analysed with quantitative approach and conducted with the use of descriptive statistical techniques. Sixty-five fishermen were interviewed. They descend from the rafting subculture of Brazil's northeast, which has historically been disregarded by public policies addressing the management and conservation of fishing resources. The fishing fleet involved in shark fishing includes rafts, fishing boats and lobster boats equipped with fishing lines, gillnets, longlines and "esperas". The informers classified sharks' behaviour repertoire into 19 ethological categories, related especially to feeding, reproduction, and social and migratory behaviours. Because they identify sharks as predators, the detailed recognition of the behaviours exhibited is crucial both for an efficient catch and to avoid accidents. Therefore, this knowledge is doubly adaptive as it contributes to safer, more lucrative fishing. A feeling of respect for sharks predominates, since informers recognize the ecological role of these animals in marine ecosystems, attributing them the status of leader (or "the man") in the sea. This work demonstrates the complexity and robustness of

  9. Shark Ig light chain junctions are as diverse as in heavy chains.

    Science.gov (United States)

    Fleurant, Marshall; Changchien, Lily; Chen, Chin-Tung; Flajnik, Martin F; Hsu, Ellen

    2004-11-01

    We have characterized a small family of four genes encoding one of the three nurse shark Ig L chain isotypes, called NS5. All NS5 cDNA sequences are encoded by three loci, of which two are organized as conventional clusters, each consisting of a V and J gene segment that can recombine and one C region exon; the third contains a germline-joined VJ in-frame and the fourth locus is a pseudogene. This is the second nurse shark L chain type where both germline-joined and split V-J organizations have been found. Since there are only two rearranging Ig loci, it was possible for the first time to examine junctional diversity in defined fish Ig genes, comparing productive vs nonproductive rearrangements. N region addition was found to be considerably more extensive in length and in frequency than any other vertebrate L chain so far reported and rivals that in H chain. We put forth the speculation that the unprecedented efficiency of N region addition (87-93% of NS5 sequences) may be a result not only of simultaneous H and L chain rearrangement in the shark but also of processing events that afford greater accessibility of the V or J gene coding ends to terminal deoxynucleotidyltransferase.

  10. Survey of shark fisheries and preparation of a National Plan of Action (NPOA) for conservation and management of shark resources in Bangladesh

    OpenAIRE

    2014-01-01

    The report presents; terms of reference; work progress; surveys of shark fishers and traders; shark biodiversity survey; and a National Plan of Action (NPOA) for conservation and management of shark resources in Bangladesh.

  11. Fisheries management and conservation of sharks in Indonesia ...

    African Journals Online (AJOL)

    Indonesian waters have a high diversity of sharks and rays, with at least 118 species belonging to 25 families found throughout the vast archipelago. Indonesia also has the highest shark landings globally and nearly all high-value shark species are overexploited and could be considered threatened. This situation is of ...

  12. White sharks Carcharodon carcharias at Bird Island, Algoa Bay ...

    African Journals Online (AJOL)

    We present the first quantitative study of the occurrence, size and sex of white sharks Carcharodon carcharias at Bird Island, Algoa Bay. Twenty-two boat trips were made to Bird Island between November 2009 and October 2011 to chum for sharks. A total of 53 sharks was observed over the study period, ranging in size ...

  13. A global perspective on the trophic geography of sharks

    DEFF Research Database (Denmark)

    Bird, Christopher S.; Verissimo, Ana; Magozzi, Sarah

    2018-01-01

    Sharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural trait...

  14. 77 FR 57022 - Drawbridge Operation Regulation; Shark River, Avon, NJ

    Science.gov (United States)

    2012-09-17

    ... Operation Regulation; Shark River, Avon, NJ AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation... across the Shark River (South Channel), at Avon Township, NJ. This deviation is necessary to facilitate stringer replacement on the Shark River railroad bridge. This temporary deviation will allow the...

  15. 78 FR 77591 - Drawbridge Operation Regulation; Shark River, NJ

    Science.gov (United States)

    2013-12-24

    ... Operation Regulation; Shark River, NJ AGENCY: Coast Guard, DHS. ACTION: Notice of deviation from drawbridge... governs the bascule span of the Route 71 Bridge across Shark River (South Channel), mile 0.8, at Belmar... motor seals and instrumentation on the bridge. The Route 71 Bridge across Shark River (South Channel...

  16. 78 FR 3836 - Drawbridge Operation Regulation; Shark River, Avon, NJ

    Science.gov (United States)

    2013-01-17

    ... Operation Regulation; Shark River, Avon, NJ AGENCY: Coast Guard, DHS. ACTION: Notice of deviation from... and the railroad bridge, mile 0.9 both of which are across the Shark River (South Channel), at Avon Township, NJ. This deviation is necessary to facilitate machinery replacement on the Shark River railroad...

  17. Recovery of human remains after shark attack.

    Science.gov (United States)

    Byard, Roger W; James, Ross A; Heath, Karen J

    2006-09-01

    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 were 2 fragments of lung. Case 2: A 19-year-old male was attacked by a great white shark while diving. A witness saw the shark swim away with the victim's body in its mouth. Again, despite intensive beach and sea searches, the only tissue recovered was a single piece of lung, along with pieces of wetsuit and diving equipment. These cases indicate that the only tissue to escape being consumed or lost in fatal shark attacks, where there is a significant attack with dismemberment and disruption of the integrity of the body, may be lung. The buoyancy of aerated pulmonary tissue ensures that it rises quickly to the surface, where it may be recovered by searchers soon after the attack. Aeration of the lung would be in keeping with death from trauma rather than from drowning and may be a useful marker in unwitnessed deaths to separate ante- from postmortem injury, using only relatively small amounts of tissues. Early organ recovery enhances the identification of human tissues as the extent of morphologic alterations by putrefactive processes and sea scavengers will have been minimized. DNA testing is also possible on such recovered fragments, enabling confirmation of the identity of the victim.

  18. Fatal tiger shark, Galeocerdo cuvier attack in New Caledonia erroneously ascribed to great white shark, Carcharodon carcharias

    OpenAIRE

    Tirard, P.; Maillaud, C.; Borsa, Philippe

    2015-01-01

    International audience; 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...

  19. Hypermutation in shark immunoglobulin light chain genes results in contiguous substitutions.

    Science.gov (United States)

    Lee, Susan S; Tranchina, Daniel; Ohta, Yuko; Flajnik, Martin F; Hsu, Ellen

    2002-04-01

    Among 631 substitutions present in 90 nurse shark immunoglobulin light chain somatic mutants, 338 constitute 2-4 bp stretches of adjacent changes. An absence of mutations in perinatal sequences and the bias for one mutating V gene in adults suggest that the diversification is antigen dependent. The substitutions shared no patterns, and the absence of donor sequences, including from family members, supports the idea that most changes arose from nontemplated mutation. The tandem mutations as a group are distinguished by consistently fewer transition changes and an A bias. We suggest this is one of several pathways of hypermutation diversifying shark antigen-receptor genes--point mutations, tandem mutations, and mutations with a G-C preference--that coevolved with or preceded gene rearrangement.

  20. Grey literature in meta-analyses.

    Science.gov (United States)

    Conn, Vicki S; Valentine, Jeffrey C; Cooper, Harris M; Rantz, Marilyn J

    2003-01-01

    In meta-analysis, researchers combine the results of individual studies to arrive at cumulative conclusions. Meta-analysts sometimes include "grey literature" in their evidential base, which includes unpublished studies and studies published outside widely available journals. Because grey literature is a source of data that might not employ peer review, critics have questioned the validity of its data and the results of meta-analyses that include it. To examine evidence regarding whether grey literature should be included in meta-analyses and strategies to manage grey literature in quantitative synthesis. This article reviews evidence on whether the results of studies published in peer-reviewed journals are representative of results from broader samplings of research on a topic as a rationale for inclusion of grey literature. Strategies to enhance access to grey literature are addressed. The most consistent and robust difference between published and grey literature is that published research is more likely to contain results that are statistically significant. Effect size estimates of published research are about one-third larger than those of unpublished studies. Unfunded and small sample studies are less likely to be published. Yet, importantly, methodological rigor does not differ between published and grey literature. Meta-analyses that exclude grey literature likely (a) over-represent studies with statistically significant findings, (b) inflate effect size estimates, and (c) provide less precise effect size estimates than meta-analyses including grey literature. Meta-analyses should include grey literature to fully reflect the existing evidential base and should assess the impact of methodological variations through moderator analysis.

  1. Characterization and anaerobic biodegradability of grey water

    NARCIS (Netherlands)

    Hernandez Leal, L.; Temmink, B.G.; Zeeman, G.; Buisman, C.J.N.

    2011-01-01

    Grey water consists of the discharges from kitchen sinks, showers, baths, washing machines and hand basins. Thorough characterization of 192 time proportional samples of grey water from 32 houses was conducted over a period of 14 months. COD concentrations were 724 ± 150 mg L- 1, of which 34% was

  2. Heterotopic grey matter: Ct vs. MRI

    International Nuclear Information System (INIS)

    Hosten, N.; Schoerner, W.

    1989-01-01

    Heterotopic grey matter is a rare cause of seizures. While lesions appear suspicious on CT because of equidensity to cortex, MR imaging can establish the diagnosis by demonstrating same signal intensity of heterotopia and grey matter on T 1 - and T 2 -weighted as well as inversion-recovery sequences. (orig.) [de

  3. Grey-Turner's sign in sclerosing peritonitis

    NARCIS (Netherlands)

    Stouthard, J. M.; Krediet, R. T.; Arisz, L.

    1989-01-01

    A 41-year-old CAPD patient developed Grey-Turner's sign during the course of bacterial peritonitis due to Pseudomonas aeruginosa. At the same time a diagnosis of sclerosing peritonitis was made by CT-scanning of the abdomen. We think that Grey-Turner's flank staining could either have been caused by

  4. Something worth remembering: visual discrimination in sharks.

    Science.gov (United States)

    Fuss, Theodora; Schluessel, Vera

    2015-03-01

    This study investigated memory retention capabilities of juvenile gray bamboo sharks (Chiloscyllium griseum) using two-alternative forced-choice experiments. The sharks had previously been trained in a range of visual discrimination tasks, such as distinguishing between squares, triangles and lines, and their corresponding optical illusions (i.e., the Kanizsa figures or Müller-Lyer illusions), and in the present study, we tested them for memory retention. Despite the absence of reinforcement, sharks remembered the learned information for a period of up to 50 weeks, after which testing was terminated. In fish, as in other vertebrates, memory windows vary in duration depending on species and task; while it may seem beneficial to retain some information for a long time or even indefinitely, other information may be forgotten more easily to retain flexibility and save energy. The results of this study indicate that sharks are capable of long-term memory within the framework of selected cognitive skills. These could aid sharks in activities such as food retrieval, predator avoidance, mate choice or habitat selection and therefore be worth being remembered for extended periods of time. As in other cognitive tasks, intraspecific differences reflected the behavioral breadth of the species.

  5. Locating grey literature on communication disorders.

    Science.gov (United States)

    Shpilko, Inna

    2005-01-01

    This article provides an overview of selected Web-based resources containing grey literature in the area of communication disorders. It is geared to practitioners, researchers, students, and consumers seeking reliable, freely available scientific information. Grey (or gray) literature has been defined as "that which is produced on all levels of government, academics, business, and industry in print and electronic formats, but which is not controlled by commercial publishers."1 This paper reviews various general reference sources potentially containing grey literature on communication disorders. This review includes identification of the methods specialists in this field use to obtain this valuable, yet often overlooked, literature. Access points and search tools for identifying grey literature on communication disorders are recommended. Commercial databases containing grey literature are not included. Conclusions presented in this article are considered complementary to traditionally published information resources on communication disorders, such as scholarly journals, online databases, etc.

  6. Bacteriology of the teeth from a great white shark: potential medical implications for shark bite victims.

    Science.gov (United States)

    Buck, J D; Spotte, S; Gadbaw, J J

    1984-11-01

    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 for representatives of Vibrio isolates and indicate that a variety of new agents may be appropriate chemotherapy for shark bite victims.

  7. Shark tales: a molecular species-level phylogeny of sharks (Selachimorpha, Chondrichthyes).

    Science.gov (United States)

    Vélez-Zuazo, Ximena; Agnarsson, Ingi

    2011-02-01

    Sharks are a diverse and ecologically important group, including some of the ocean's largest predatory animals. Sharks are also commercially important, with many species suffering overexploitation and facing extinction. However, despite a long evolutionary history, commercial, and conservation importance, phylogenetic relationships within the sharks are poorly understood. To date, most studies have either focused on smaller clades within sharks, or sampled taxa sparsely across the group. A more detailed species-level phylogeny will offer further insights into shark taxonomy, provide a tool for comparative analyses, as well as facilitating phylogenetic estimates of conservation priorities. We used four mitochondrial and one nuclear gene to investigate the phylogenetic relationships of 229 species (all eight Orders and 31 families) of sharks, more than quadrupling the number of taxon sampled in any prior study. The resulting Bayesian phylogenetic hypothesis agrees with prior studies on the major relationships of the sharks phylogeny; however, on those relationships that have proven more controversial, it differs in several aspects from the most recent molecular studies. The phylogeny supports the division of sharks into two major groups, the Galeomorphii and Squalimorphii, rejecting the hypnosqualean hypothesis that places batoids within sharks. Within the squalimorphs the orders Hexanchiformes, Squatiniformes, Squaliformes, and Pristiophoriformes are broadly monophyletic, with minor exceptions apparently due to missing data. Similarly, within Galeomorphs, the orders Heterodontiformes, Lamniformes, Carcharhiniformes, and Orectolobiformes are broadly monophyletic, with a couple of species 'misplaced'. In contrast, many of the currently recognized shark families are not monophyletic according to our results. Our phylogeny offers some of the first clarification of the relationships among families of the order Squaliformes, a group that has thus far received relatively

  8. 78 FR 59878 - Atlantic Highly Migratory Species; Commercial Atlantic Aggregated Large Coastal Shark (LCS...

    Science.gov (United States)

    2013-09-30

    ... Coastal Shark (LCS), Atlantic Hammerhead Shark, Atlantic Blacknose Shark, and Atlantic Non-Blacknose Small Coastal Shark (SCS) Management Groups AGENCY: National Marine Fisheries Service (NMFS), National Oceanic... closing the commercial management groups for aggregated LCS and hammerhead sharks in the Atlantic region...

  9. On Sharks, Trolls, and Other Patent Animals

    DEFF Research Database (Denmark)

    Reitzig, Markus; Henkel, Joachim; Heath, Christopher

    2007-01-01

    Patent trolls (or sharks) are small patent holding individuals or firms who trap R&D intense manufacturers in patent infringement situations in order to receive damage awards for the illegitimate use of their technology. While of great concern to management, their existence and impact for both...... corporate decision makers and policy makers remains to be fully analyzed from an academic standpoint. In this paper we show why patent sharks can operate profitably, why they are of growing concern, how manufacturers can forearm themselves against them, and which issues policy makers need to address. To do...... so, we map international indemnification rules with strategic rationales of small patent-holding firms within a game-theoretical model. Our central finding is that the courts’ unrealistic consideration of the trade-offs faced by inadvertent infringers is a central condition for sharks to operate...

  10. Active predation by Greenland shark Somniosus microcephalus

    DEFF Research Database (Denmark)

    Nielsen, Julius; hedeholm, Rasmus; Simon, Malene

    2013-01-01

    and show that the sharks catch epi-benthic species with Atlantic cod being the most important (% IRI = 56 ), followed by squid (% IRI= 13 ) and wolf fish (IRI=4). Furthermore seal was found in 50 % of all stomachs (% IRI= 13). In addition to providing new knowledge of feeding habits of this species......Dansk Havforskermøde 2013 Julius Nielsen, Rasmus Hedeholm, Malene Simon og John Fleng Steffensen The Greenland shark is ubiquitous in the northern part of the North Atlantic ranging from eastern Canada to northwest Russia . Although knowledge is scarce it is believed to be abundant and potentially...... important part of the ecosystem. Whether Greenland sharks in general should be considered opportunistic scavengers or active predators is therefore important in understanding ecosystem dynamics. Due to its sluggish appearance and a maximum reported swimming speed of 74 cm per second scavenging seems...

  11. Allometric relationships of the dentition of the great White Shark, Carcharodon carcharias, in forensic investigations of shark attacks

    OpenAIRE

    Nambiar, P.; Bridges, T. E.; Brown, K. A.

    2017-01-01

    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 ...

  12. A new gnathiid (Crustacea: Isopoda) parasitizing two species of requiem sharks from Lizard Island, Great Barrier Reef, Australia.

    Science.gov (United States)

    Coetzee, Maryke L; Smit, Nico J; Grutter, Alexandra S; Davies, Angela J

    2008-06-01

    Third-stage juveniles (praniza 3) of Gnathia grandilaris n. sp. were collected from the gill filaments and septa of 5 requiem sharks, including a white tip reef shark, Triaenodon obesus, and 4 grey reef sharks, Carcharhinus amblyrhynchos, at Lizard Island, Great Barrier Reef, Australia, in March 2002. Some juvenile gnathiids were then maintained in fresh sea water until they molted to adults. Adult males appeared 19 days following detachment of juveniles from host fishes, but no juveniles molted successfully into females. The current description is based, therefore, on bright field and scanning electron microscopy observations of adult males and third-stage juveniles. Unique features of the male include the triangular-shaped inferior medio-frontal process, 2 areolae on the dorsal surface of the pylopod, and a slender pleotelson (twice as long as wide) with lateral concavities. The third-stage juvenile has distinctive white pigmentation on the black pereon when alive, while the mandible has 9 triangular backwardly directed teeth. This species has the largest male and third-stage juvenile of any Gnathia spp. from Australia and of any gnathiid isopods associated with elasmobranchs.

  13. Biological responses of sharks to ocean acidification.

    Science.gov (United States)

    Rosa, Rui; Rummer, Jodie L; Munday, Philip L

    2017-03-01

    Sharks play a key role in the structure of marine food webs, but are facing major threats due to overfishing and habitat degradation. Although sharks are also assumed to be at relatively high risk from climate change due to a low intrinsic rate of population growth and slow rates of evolution, ocean acidification (OA) has not, until recently, been considered a direct threat. New studies have been evaluating the potential effects of end-of-century elevated CO 2 levels on sharks and their relatives' early development, physiology and behaviour. Here, we review those findings and use a meta-analysis approach to quantify the overall direction and magnitude of biological responses to OA in the species of sharks that have been investigated to date. While embryo survival and development time are mostly unaffected by elevated CO 2 , there are clear effects on body condition, growth, aerobic potential and behaviour (e.g. lateralization, hunting and prey detection). Furthermore, studies to date suggest that the effects of OA could be as substantial as those due to warming in some species. A major limitation is that all past studies have involved relatively sedentary, benthic sharks that are capable of buccal ventilation-no studies have investigated pelagic sharks that depend on ram ventilation. Future research should focus on species with different life strategies (e.g. pelagic, ram ventilators), climate zones (e.g. polar regions), habitats (e.g. open ocean), and distinct phases of ontogeny in order to fully predict how OA and climate change will impact higher-order predators and therefore marine ecosystem dynamics. © 2017 The Author(s).

  14. Allometric relationships of the dentition of the great White Shark, Carcharodon carcharias, in forensic investigations of shark attacks.

    Science.gov (United States)

    Nambiar, P; Bridges, T E; Brown, K A

    1991-06-01

    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 developed which can be used to estimate the body length of a White Shark from measurements of tooth or bite mark morphology. An example of the forensic application of such allometric data is provided as it applied to a recent fatal attack on a diver by a White Shark.

  15. Fatal tiger shark, Galeocerdo cuvier attack in New Caledonia erroneously ascribed to great white shark, Carcharodon carcharias.

    Science.gov (United States)

    Tirard, Philippe; Maillaud, Claude; Borsa, Philippe

    2015-07-01

    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 victim, here documented by so-far unpublished photographic evidence, determined that the shark possessed large and homodontous jaws. This demonstrates that the attacker was a tiger shark, not a great white shark as previously published. Copyright © 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  16. Bacteriology of the teeth from a great white shark: potential medical implications for shark bite victims.

    OpenAIRE

    Buck, J D; Spotte, S; Gadbaw, J J

    1984-01-01

    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 sh...

  17. 75 FR 9158 - Atlantic Coastal Fisheries Cooperative Management Act Provisions; Coastal Sharks Fishery

    Science.gov (United States)

    2010-03-01

    ... Coastal Fisheries Cooperative Management Act Provisions; Coastal Sharks Fishery AGENCY: National Marine... Commission's Interstate Fishery Management Plan (ISFMP) for Coastal Sharks. Subsequently, the Commission... New Jersey failed to carry out its responsibilities under the Coastal Sharks ISFMP, and if the...

  18. Monogenoid infection of neonatal and older juvenile lemon sharks, Negaprion brevirostris (Carcharhinidae), in a shark nursery.

    Science.gov (United States)

    Young, Joy M; Frasca, Salvatore; Gruber, Samuel H; Benz, George W

    2013-12-01

    Fifty lemon sharks, Negaprion brevirostris , were captured in a shallow, mangrove-fringed shark nursery at Bimini, Bahamas and examined for the presence of skin-dwelling ectoparasitic monogenoids (Monogenoidea). Sixteen sharks were infected by Dermophthirius nigrellii (Microbothriidae); the youngest host was estimated to be 3- to 4-wk-old. Infection prevalence, mean intensity, and median intensity (0.32, 2.63, and 2.0, respectively, for all sharks) were not significantly different between neonates (estimated ages 3- to 10-wk-old) and non-neonatal juveniles (estimated ages 1- to 4-yr-old), suggesting that soon after parturition lemon sharks acquire infection levels of D. nigrellii matching those of juvenile conspecifics. Monogenoids were only found on the trailing portion of the first and second dorsal fins and upper lobe of the caudal fin. The prevalence of D. nigrellii was highest on the first dorsal fin; however, the mean and median intensities of D. nigrellii were similar between fins in all but 1 case. These results raise important husbandry implications regarding the practice of preferentially seeking neonatal and other small lemon sharks for captivity.

  19. Isolation of the new antigen receptor from wobbegong sharks, and use as a scaffold for the display of protein loop libraries.

    Science.gov (United States)

    Nuttall, S D; Krishnan, U V; Hattarki, M; De Gori, R; Irving, R A; Hudson, P J

    2001-08-01

    The new antigen receptor (NAR) from nurse sharks consists of an immunoglobulin variable domain attached to five constant domains, and is hypothesised to function as an antigen-binding antibody-like molecule. To determine whether the NAR is present in other species we have isolated a number of new antigen receptor variable domains from the spotted wobbegong shark (Orectolobus maculatus) and compared their structure to that of the nurse shark protein. To determine whether these wNARs can function as antigen-binding proteins, we have used them as scaffolds for the construction of protein libraries in which the CDR3 loop was randomised, and displayed the resulting recombinant domains on the surface of fd bacteriophages. On selection against several protein antigens, the highest affinity wNAR proteins were generated against the Gingipain K protease from Porphyromonas gingivalis. One wNAR protein bound Gingipain K specifically by ELISA and BIAcore analysis and, when expressed in E. coli and purified by affinity chromatography, eluted from an FPLC column as a single peak consistent with folding into a monomeric protein. Naturally occurring nurse shark and wobbegong NAR variable domains exhibit conserved cysteine residues within the CDR1 and CDR3 loops which potentially form disulphide linkages and enhance protein stability; proteins isolated from the in vitro NAR wobbegong library showed similar selection for such paired cysteine residues. Thus, the New Antigen Receptor represents a protein scaffold with possible stability advantages over conventional antibodies when used in in vitro molecular libraries.

  20. Shark IgW C region diversification through RNA processing and isotype switching.

    Science.gov (United States)

    Zhang, Cecilia; Du Pasquier, Louis; Hsu, Ellen

    2013-09-15

    Sharks and skates represent the earliest vertebrates with an adaptive immune system based on lymphocyte Ag receptors generated by V(D)J recombination. Shark B cells express two classical Igs, IgM and IgW, encoded by an early, alternative gene organization consisting of numerous autonomous miniloci, where the individual gene cluster carries a few rearranging gene segments and one C region, μ or ω. We have characterized eight distinct Ig miniloci encoding the nurse shark ω H chain. Each cluster consists of VH, D, and JH segments and six to eight C domain exons. Two interspersed secretory exons, in addition to the 3'-most C exon with tailpiece, provide the gene cluster with the ability to generate at least six secreted isoforms that differ as to polypeptide length and C domain combination. All clusters appear to be functional, as judged by the capability for rearrangement and absence of defects in the deduced amino acid sequence. We previously showed that IgW VDJ can perform isotype switching to μ C regions; in this study, we found that switching also occurs between ω clusters. Thus, C region diversification for any IgW VDJ can take place at the DNA level by switching to other ω or μ C regions, as well as by RNA processing to generate different C isoforms. The wide array of pathogens recognized by Abs requires different disposal pathways, and our findings demonstrate complex and unique pathways for C effector function diversity that evolved independently in cartilaginous fishes.

  1. Link managers for grey literature

    CERN Document Server

    Lodi-Rizzini, E; Vigen, Jens

    1999-01-01

    In the self service area of the library reading rooms it is required to organise the collections in the simplest way possible. This is an important feature for readers making it possible to a get direct access to the material without necessarily having to go via the library catalogue to retrieve the call number. A typical example will be that a collection is organised so that a reader easily can get directly from an article reference to the article itself in a library where the journal collection simply is organised alphabetically. This requirement seems to have been forgotten by many of the most important actors in the digital library, both by the commercial publishers and many of the bodies producing grey literature. How are the users supposed to get directly to Report XXX without having to navigate through n different web pages? This is on top happening in "The Library" which is intended to be close up to 100 based on self service! CERN Library has developed a mechanism, "Go direct", which handles the prob...

  2. INIS: Nuclear Grey Literature Repository

    International Nuclear Information System (INIS)

    Savić, Dobrica

    2016-01-01

    As one of the world's largest collections of published information on the peaceful uses of nuclear science and technology, INIS represents an extraordinary example of world cooperation. Currently, as INIS members, 130 countries and 24 international organizations share and allow access to their valuable nuclear information resources, preserving them for future generations and offering a freely available nuclear knowledge repository. Since its creation in 1970, INIS has collected and provided access to more than 3.8 million bibliographic references to publications, documents, technical reports, non-copyrighted documentation, and other grey literature, as well as over a million full texts. Public interest throughout the years in accessing the INIS Collection has been remarkable. This paper deals with the challenges faced by INIS in its endeavour to increase the use, accessibility, usability and expandability of its on-line repository. It also describes document collection, the features and characteristics of implementing a new search engine, as well as the lessons learned. (author)

  3. Sharks eating mosasaurs, dead or alive?

    NARCIS (Netherlands)

    Rothschild, B. M.; Martin, L. D.; Schulp, A. S.

    Shark bite marks on mosasaur bones abound in the fossil record. Here we review examples from Kansas (USA) and the Maastrichtian type area (SE Netherlands, NE Belgium), and discuss whether they represent scavenging and/or predation. Some bite marks are most likely the result of scavenging. On the

  4. GreyGuide - Guide to Good Practice in Grey Literature: A Community Driven Open Resource Project

    OpenAIRE

    Biagioni, Stefania (ISTI-CNR); Carlesi, Carlo (ISTI-CNR); Schopfel, Joachim (University of Lille); Farace, Dominic J. (GreyNet); Frantzen, Jerry (GreyNet); GreyNet, Grey Literature Network Service

    2014-01-01

    The goal of this project is to develop an open source repository of good practices in the field of grey literature. That which originated in monographic form will now open and expand to include content from the global grey literature community. Such practices will range from the production and processing of grey literature through to its distribution, uses, and preservation. The repository will contain guidelines such as those in handling theses and dissertations, how to write research report...

  5. Application of Grey Theory in Operator Management

    International Nuclear Information System (INIS)

    Xu, Hong

    2011-01-01

    Scientific and reasonable operator management is the basis of nuclear security. It was paid more attention after the three-mile island accident. The prediction of operators' basic behavior parameters is the premise and foundation of scientific and reasonable operator management. Grey theory happens to solve the dilemma encountered in prediction and decision-making of operator behavior in operator management of NPP. The procedure is divided into two steps: according to the history record of operators' behavior parameter, a differential equation model using grey theory is set up to predict the future behavior of operators and use grey theory to make decision for operator management. The calculation result is helpful for operator management and also useful for operators to find their shortcoming. Grey theory using in the study provides a new idea and method for future operator management in NPP

  6. Application of grey theory in operator management

    International Nuclear Information System (INIS)

    Xu Hong

    2013-01-01

    Scientific and reasonable operator management is the basis of nuclear safety. It is paid more attention after the three-mile island accident. The prediction of operators' basic behavior parameters is the premise and foundation of scientific and reasonable operator management. Grey theory happened to solve the dilemma encountered in prediction and decision-making of operator behavior in operator management of nuclear power plant. The procedure was divided into two steps: 1) According to the historical record of operators' behavior parameters, a differential equation model using grey theory was set up to predict the future behavior of operators; 2) operator management decision-making was made based on grey theory. The calculation result is not only helpful for operator management but also useful for operators to find their shortcomings. Grey theory used in the study provides a new idea and method for future operator management in nuclear power plant. (author)

  7. The 'grey' assessment practice of IA screening

    DEFF Research Database (Denmark)

    Bidstrup, Morten

    2017-01-01

    Research focusing on the practices surrounding screening in Impact Assessment (IA) is limited. Yet, it has been found that development proposals sometimes are adjusted through an informal dialog with IA practitioners prior to or during screening. Such practice is often referred to as ‘grey IA......’ in Denmark. This article explores the prevalence, influence and applied rationale of grey IA. Through a questionnaire, data was collected from 121 IA practitioners working within the fields of environmental impact assessment and strategic environmental assessment. It was found that grey IA is a common...... practice, which influences the outcomes of formal screening procedures through consideration of impacts on neighbours and spatial zones of protection. Grey IA is to some extent motivated by the opportunity to save the resources required for full-scale IA, but an additional ‘green’ rationale also exists...

  8. MRI of laminar heterotopic grey matter

    International Nuclear Information System (INIS)

    Vahldiek, G.; Terwey, B.; Hanefeld, F.; Sperner, J.

    1990-01-01

    In one baby and 2 infants who presented with psychomotor retardation and epilepsy laminar heterotopic grey matter was demonstrated via magnetic resonance imaging. Laminar heterotopia is a rare migrational disorder with bilateral symmetric ribbons of grey matter within the centrum semiovale, separated from ventricular walls and from obviously normal-sized cortex by broad layers of white matter. The heterotopic grey matter has a signal intensity which is isointense compared with that of normal cortex irrespective of image weighting. On account of this signal behaviour differentiation against other white matter diseases is easy. The knowledge of these pathognomonic findings facilitates correct diagnosis, especially during the first and the second year of life, when signal intensities of white and grey matter differ from normal findings because of the occasionally delayed myelination process. Therefore, further diagnostic procedures can be avoided and early counseling of parents is possible. (orig.) [de

  9. The potential of grey alder plantation forestry

    Energy Technology Data Exchange (ETDEWEB)

    Rytter, L. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Short Rotation Forestry

    1996-12-31

    A survey concerning the potential use of grey alder (Alnus incana (L.) Moench.) in short rotation forestry is performed. The most important characters in this context are discussed. It is concluded that grey alder is an interesting contributor in plantation forestry, because it has a high woody biomass production, is more or less self-supporting with nitrogen, and is well adapted to the conditions in Fennoscandia and Balticum. 36 refs, 2 figs, 1 tab

  10. Grey literature for development: Some case studies

    OpenAIRE

    Sen, B. (SHPT); GreyNet, Grey Literature Network Service

    2007-01-01

    Grey Literature refers to publications issued by government, academia, business, and industry, in both print and electronic formats, but not controlled by commercial publishing interests, and where publishing is not the primary business activity of the organization. Newsletters, reports, working papers, theses, government documents, bulletins, fact sheets, conference proceedings and other publications distributed free, available by subscription, or for sale comprises grey literature. Non-prof...

  11. The Greenland shark (Somniosus microcephalus)

    DEFF Research Database (Denmark)

    Nielsen, Julius

    radiocarbon dating and a Bayesian calibration model to estimate longevity of the Greenland shark. The analyzed tissue stems from the eye lens nucleus – unique material which presumably reflects age 0 of the shark, as it has not undergone metabolic changes during the animal’s life. By studying 28 Greenland...... shark females between 81 cm and 502 cm, I estimate the oldest shark to be between 272 years and 512 years. With an estimated lifespan of at least 272 years, the Greenland shark is the longest living vertebrate animal in the world. In order to produce these age estimates, it has been necessary to study...... continental shelf waters in southern Greenland at depths between 200 and 550 m and fed primarily on cod, redfish and seals. From previous investigations of predatory sharks and whales in the north Atlantic, bomb radiocarbon has been widely applied, and I argue that a similar calibration approach is valid...

  12. Sharks in Captivity: The Role of Husbandry, Breeding, Education, and Citizen Science in Shark Conservation.

    Science.gov (United States)

    Grassmann, Michael; McNeil, Bryan; Wharton, Jim

    The role of public aquariums in promoting conservation has changed substantially over the decades, evolving from entertainment attractions to educational and research centres. In many facilities, larger sharks are an essential part of the collection and represent one of the biggest draws for the public. Displaying healthy elasmobranchs comes with many challenges, but improvements in husbandry techniques have enabled aquariums to have success with a variety of species. The establishment of organisations such as the Association of Zoos and Aquariums, and the completion of texts like the Elasmobranch Husbandry Manual, has helped set high standards of care for sharks in captivity and promoted international conservation efforts. Aquariums keeping sharks are in a unique position to influence local, regional, and international attitudes and policies by acting as both educational and research facilities. Interactions with multiple stakeholders of diverse educational and demographic backgrounds through the use of in-house advocacy, public outreach, media interviews, and partnerships with academic and government institutions enable these facilities to engage and share information with a broad audience. Although the data collected on sharks in captivity often cannot be directly translated to animals in the wild, it offers better insight into a number of life history traits and poorly understood behaviours, and has been the foundation for many captive breeding programs. Several Northeast Pacific (NEP) shark species are commonly displayed for long durations or bred in aquariums, while other less studied species have been held for short periods to collect valuable data that can be applied towards ongoing studies and conservation measures. Here, we discuss past and current tangible benefits of holding NEP sharks in captivity, as well as noting several ways in which future research and education activities will continue to inform and shape public opinions on shark management and

  13. Seasonal and long-term changes in relative abundance of bull sharks from a tourist shark feeding site in Fiji.

    Science.gov (United States)

    Brunnschweiler, Juerg M; Baensch, Harald

    2011-01-27

    Shark tourism has become increasingly popular, but remains controversial because of major concerns originating from the need of tour operators to use bait or chum to reliably attract sharks. We used direct underwater sampling to document changes in bull shark Carcharhinus leucas relative abundance at the Shark Reef Marine Reserve, a shark feeding site in Fiji, and the reproductive cycle of the species in Fijian waters. Between 2003 and 2009, the total number of C. leucas counted on each day ranged from 0 to 40. Whereas the number of C. leucas counted at the feeding site increased over the years, shark numbers decreased over the course of a calendar year with fewest animals counted in November. Externally visible reproductive status information indicates that the species' seasonal departure from the feeding site may be related to reproductive activity.

  14. Thresher sharks use tail-slaps as a hunting strategy.

    Science.gov (United States)

    Oliver, Simon P; Turner, John R; Gann, Klemens; Silvosa, Medel; D'Urban Jackson, Tim

    2013-01-01

    The hunting strategies of pelagic thresher sharks (Alopias pelagicus) were investigated at Pescador Island in the Philippines. It has long been suspected that thresher sharks hunt with their scythe-like tails but the kinematics associated with the behaviour in the wild are poorly understood. From 61 observations recorded by handheld underwater video camera between June and October 2010, 25 thresher shark shunting events were analysed. Thresher sharks employed tail-slaps to debilitate sardines at all times of day. Hunting events comprised preparation, strike, wind-down recovery and prey item collection phases, which occurred sequentially. Preparation phases were significantly longer than the others, presumably to enable a shark to windup a tail-slap. Tail-slaps were initiated by an adduction of the pectoral fins, a manoeuvre that changed a thresher shark's pitch promoting its posterior region to lift rapidly, and stall its approach. Tail-slaps occurred with such force that they may have caused dissolved gas to diffuse out of the water column forming bubbles. Thresher sharks were able to consume more than one sardine at a time, suggesting that tail-slapping is an effective foraging strategy for hunting schooling prey. Pelagic thresher sharks appear to pursue sardines opportunistically by day and night, which may make them vulnerable to fisheries. Alopiids possess specialist pectoral and caudal fins that are likely to have evolved, at least in part, for tail-slapping. The evidence is now clear; thresher sharks really do hunt with their tails.

  15. Social learning in juvenile lemon sharks, Negaprion brevirostris.

    Science.gov (United States)

    Guttridge, Tristan L; van Dijk, Sander; Stamhuis, Eize J; Krause, Jens; Gruber, Samuel H; Brown, Culum

    2013-01-01

    Social learning is taxonomically widespread and can provide distinct behavioural advantages, such as in finding food or avoiding predators more efficiently. Although extensively studied in bony fishes, no such empirical evidence exists for cartilaginous fishes. Our aim in this study was to experimentally investigate the social learning capabilities of juvenile lemon sharks, Negaprion brevirostris. We designed a novel food task, where sharks were required to enter a start zone and subsequently make physical contact with a target in order to receive a food reward. Naive sharks were then able to interact with and observe (a) pre-trained sharks, that is, 'demonstrators', or (b) sharks with no previous experience, that is, 'sham demonstrators'. On completion, observer sharks were then isolated and tested individually in a similar task. During the exposure phase observers paired with 'demonstrator' sharks performed a greater number of task-related behaviours and made significantly more transitions from the start zone to the target, than observers paired with 'sham demonstrators'. When tested in isolation, observers previously paired with 'demonstrator' sharks completed a greater number of trials and made contact with the target significantly more often than observers previously paired with 'sham demonstrators'. Such experience also tended to result in faster overall task performance. These results indicate that juvenile lemon sharks, like numerous other animals, are capable of using socially derived information to learn about novel features in their environment. The results likely have important implications for behavioural processes, ecotourism and fisheries.

  16. CATCH COMPOSITION AND SOME BIOLOGICAL ASPECTS OF SHARKS IN WESTERN SUMATERA WATERS OF INDONESIA

    Directory of Open Access Journals (Sweden)

    Dharmadi Dharmadi

    2017-01-01

    Full Text Available This study was conducted in western Sumatera and since October 2013 to June 2014. The sampling locations in Banda Aceh and Sibolga-North Sumatera which were the largest base of fisheries in western Sumatera region. Shark landing recorded by enumerators was used  as sampling data daily . This research aim to describ sex ratio, size composition, catch composition of sharks, and length at first maturity. In Banda Aceh, the sharks as target fish collected by  sorting the bycatch from tuna longlines and tuna handlines. In Sibolga, sharks  is bycatch from fish net, bottom gillnet and purse seine. Overall, there were 20 species of shark caught in west Indian Ocean and landed at those fish landing sites, dominated by Spot tail shark (23% and Silky shark (13%, whereas Hammerhead shark contributed about 10% and  Oceanic whitetip shark was only less than 1%. Almost of Spot tail shark, Silky shark, and Scalloped hammerhead that caught in that area were  immature, while for the almost part of Tiger shark and Pelagic thresher were  matured. The sex ratios for Spot tail shark, Silky shark, Tiger shark, Pelagic thresher, and Scalloped hammerhead caught and landed at Lampulo and Sibolga fish landing sites were not balance. The length at first maturity for Spot tail shark was Lm=87,1 cm and Lm = 213,2 cm total length for Tiger shark.

  17. Unprovoked fatal shark attack in Lifou Island (Loyalty Islands, New Caledonia, South Pacific) by a great white shark, Carcharodon carcharias.

    Science.gov (United States)

    Clua, Eric; Séret, Bernard

    2010-09-01

    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 great white shark, Carcharodon carcharias.

  18. Selection of cholera toxin specific IgNAR single-domain antibodies from a naïve shark library.

    Science.gov (United States)

    Liu, Jinny L; Anderson, George P; Delehanty, James B; Baumann, Richard; Hayhurst, Andrew; Goldman, Ellen R

    2007-03-01

    Shark immunoglobulin new antigen receptor (IgNAR, also referred to as NAR) variable domains (Vs) are single-domain antibody (sdAb) fragments containing only two hypervariable loop structures forming 3D topologies for a wide range of antigen recognition and binding. Their small size ( approximately 12kDa) and high solubility, thermostability and binding specificity make IgNARs an exceptional alternative source of engineered antibodies for sensor applications. Here, two new shark NAR V display libraries containing >10(7) unique clones from non-immunized (naïve) adult spiny dogfish (Squalus acanthias) and smooth dogfish (Mustelus canis) sharks were constructed. The most conserved consensus sequences derived from random clone sequence were compared with published nurse shark (Ginglymostoma cirratum) sequences. Cholera toxin (CT) was chosen for panning one of the naïve display libraries due to its severe pathogenicity and commercial availability. Three very similar CT binders were selected and purified soluble monomeric anti-CT sdAbs were characterized using Luminex(100) and traditional ELISA assays. These novel anti-CT sdAbs selected from our newly constructed shark NAR V sdAb library specifically bound to soluble antigen, without cross reacting with other irrelevant antigens. They also showed superior heat stability, exhibiting slow loss of activity over the course of one hour at high temperature (95 degrees C), while conventional antibodies lost all activity in the first 5-10min. The successful isolation of target specific sdAbs from one of our non-biased NAR libraries, demonstrate their ability to provide binders against an unacquainted antigen of interest.

  19. Application of grey system theory in telecare.

    Science.gov (United States)

    Huang, Jui-Chen

    2011-05-01

    As a superiority to conventional statistical models, grey models require only a limited amount of data to estimate the behaviour of unknown systems. Grey system theory can be used in the effective factor assessment, and used in large samples where data are not available or uncertain whether the data was representative. Therefore, the purpose of this study was to adopt grey system theory to discuss older adult users' opinions on the telecare and its effect on their quality of life. This study surveyed the older adult users of Taiwan as subjects. User perception of the telecare services was collected via face-to-face interview. The grey system theory was used to examine the model. The results showed that the overall living quality has the greatest effect on the perceived effects of the telecare on their quality of life, followed by the acquisition of information, accessibility of medical care services, and safety. This finding may serve as a reference to future studies and it also shows that the grey system theory is a feasible analysis method. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Spinal cord grey matter segmentation challenge.

    Science.gov (United States)

    Prados, Ferran; Ashburner, John; Blaiotta, Claudia; Brosch, Tom; Carballido-Gamio, Julio; Cardoso, Manuel Jorge; Conrad, Benjamin N; Datta, Esha; Dávid, Gergely; Leener, Benjamin De; Dupont, Sara M; Freund, Patrick; Wheeler-Kingshott, Claudia A M Gandini; Grussu, Francesco; Henry, Roland; Landman, Bennett A; Ljungberg, Emil; Lyttle, Bailey; Ourselin, Sebastien; Papinutto, Nico; Saporito, Salvatore; Schlaeger, Regina; Smith, Seth A; Summers, Paul; Tam, Roger; Yiannakas, Marios C; Zhu, Alyssa; Cohen-Adad, Julien

    2017-05-15

    An important image processing step in spinal cord magnetic resonance imaging is the ability to reliably and accurately segment grey and white matter for tissue specific analysis. There are several semi- or fully-automated segmentation methods for cervical cord cross-sectional area measurement with an excellent performance close or equal to the manual segmentation. However, grey matter segmentation is still challenging due to small cross-sectional size and shape, and active research is being conducted by several groups around the world in this field. Therefore a grey matter spinal cord segmentation challenge was organised to test different capabilities of various methods using the same multi-centre and multi-vendor dataset acquired with distinct 3D gradient-echo sequences. This challenge aimed to characterize the state-of-the-art in the field as well as identifying new opportunities for future improvements. Six different spinal cord grey matter segmentation methods developed independently by various research groups across the world and their performance were compared to manual segmentation outcomes, the present gold-standard. All algorithms provided good overall results for detecting the grey matter butterfly, albeit with variable performance in certain quality-of-segmentation metrics. The data have been made publicly available and the challenge web site remains open to new submissions. No modifications were introduced to any of the presented methods as a result of this challenge for the purposes of this publication. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  1. The evolution of multiple isotypic IgM heavy chain genes in the shark.

    Science.gov (United States)

    Lee, Victor; Huang, Jing Li; Lui, Ming Fai; Malecek, Karolina; Ohta, Yuko; Mooers, Arne; Hsu, Ellen

    2008-06-01

    The IgM H chain gene organization of cartilaginous fishes consists of 15-200 miniloci, each with a few gene segments (V(H)-D1-D2-J(H)) and one C gene. This is a gene arrangement ancestral to the complex IgH locus that exists in all other vertebrate classes. To understand the molecular evolution of this system, we studied the nurse shark, which has relatively fewer loci, and characterized the IgH isotypes for organization, functionality, and the somatic diversification mechanisms that act upon them. Gene numbers differ slightly between individuals ( approximately 15), but five active IgM subclasses are always present. Each gene undergoes rearrangement that is strictly confined within the minilocus; in B cells there is no interaction between adjacent loci located > or =120 kb apart. Without combinatorial events, the shark IgM H chain repertoire is based on junctional diversity and, subsequently, somatic hypermutation. We suggest that the significant contribution by junctional diversification reflects the selected novelty introduced by RAG in the early vertebrate ancestor, whereas combinatorial diversity coevolved with the complex translocon organization. Moreover, unlike other cartilaginous fishes, there are no germline-joined VDJ at any nurse shark mu locus, and we suggest that such genes, when functional, are species-specific and may have specialized roles. With an entire complement of IgM genes available for the first time, phylogenetic analyses were performed to examine how the multiple Ig loci evolved. We found that all domains changed at comparable rates, but V(H) appears to be under strong positive selection for increased amino acid sequence diversity, and surprisingly, so does Cmicro2.

  2. Isolation and characterisation of Ebolavirus-specific recombinant antibody fragments from murine and shark immune libraries.

    Science.gov (United States)

    Goodchild, Sarah A; Dooley, Helen; Schoepp, Randal J; Flajnik, Martin; Lonsdale, Stephen G

    2011-09-01

    Members of the genus Ebolavirus cause fulminating outbreaks of disease in human and non-human primate populations with a mortality rate up to 90%. To facilitate rapid detection of these pathogens in clinical and environmental samples, robust reagents capable of providing sensitive and specific detection are required. In this work recombinant antibody libraries were generated from murine (single chain variable domain fragment; scFv) and nurse shark, Ginglymostoma cirratum (IgNAR V) hosts immunised with Zaire ebolavirus. This provides the first recorded IgNAR V response against a particulate antigen in the nurse shark. Both murine scFv and shark IgNAR V libraries were panned by phage display technology to identify useful antibodies for the generation of immunological detection reagents. Two murine scFv were shown to have specificity to the Zaire ebolavirus viral matrix protein VP40. Two isolated IgNAR V were shown to bind to the viral nucleoprotein (NP) and to capture viable Zaire ebolavirus with a high degree of sensitivity. Assays developed with IgNAR V cross-reacted to Reston ebolavirus, Sudan ebolavirus and Bundibugyo ebolavirus. Despite this broad reactivity, neither of IgNAR V showed reactivity to Côte d'Ivoire ebolavirus. IgNAR V was substantially more resistant to irreversible thermal denaturation than murine scFv and monoclonal IgG in a comparative test. The demonstrable robustness of the IgNAR V domains may offer enhanced utility as immunological detection reagents in fieldable biosensor applications for use in tropical or subtropical countries where outbreaks of Ebolavirus haemorrhagic fever occur. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  3. Re-creating missing population baselines for Pacific reef sharks.

    Science.gov (United States)

    Nadon, Marc O; Baum, Julia K; Williams, Ivor D; McPherson, Jana M; Zgliczynski, Brian J; Richards, Benjamin L; Schroeder, Robert E; Brainard, Russell E

    2012-06-01

    Sharks and other large predators are scarce on most coral reefs, but studies of their historical ecology provide qualitative evidence that predators were once numerous in these ecosystems. Quantifying density of sharks in the absence of humans (baseline) is, however, hindered by a paucity of pertinent time-series data. Recently researchers have used underwater visual surveys, primarily of limited spatial extent or nonstandard design, to infer negative associations between reef shark abundance and human populations. We analyzed data from 1607 towed-diver surveys (>1 ha transects surveyed by observers towed behind a boat) conducted at 46 reefs in the central-western Pacific Ocean, reefs that included some of the world's most pristine coral reefs. Estimates of shark density from towed-diver surveys were substantially lower (sharks observed in towed-diver surveys and human population in models that accounted for the influence of oceanic primary productivity, sea surface temperature, reef area, and reef physical complexity. We used these models to estimate the density of sharks in the absence of humans. Densities of gray reef sharks (Carcharhinus amblyrhynchos), whitetip reef sharks (Triaenodon obesus), and the group "all reef sharks" increased substantially as human population decreased and as primary productivity and minimum sea surface temperature (or reef area, which was highly correlated with temperature) increased. Simulated baseline densities of reef sharks under the absence of humans were 1.1-2.4/ha for the main Hawaiian Islands, 1.2-2.4/ha for inhabited islands of American Samoa, and 0.9-2.1/ha for inhabited islands in the Mariana Archipelago, which suggests that density of reef sharks has declined to 3-10% of baseline levels in these areas. ©2012 Society for Conservation Biology No claim to original US government works.

  4. An investigation into ciguatoxin bioaccumulation in sharks.

    Science.gov (United States)

    Meyer, Lauren; Capper, Angela; Carter, Steve; Simpfendorfer, Colin

    2016-09-01

    Ciguatoxins (CTXs) produced by benthic Gambierdiscus dinoflagellates, readily biotransform and bioaccumulate in food chains ultimately bioconcentrating in high-order, carnivorous marine species. Certain shark species, often feeding at, or near the top of the food-chain have the ability to bioaccumulate a suite of toxins, from both anthropogenic and algal sources. As such, these apex predators are likely sinks for CTXs. This assumption, in conjunction with anecdotal knowledge of poisoning incidents, several non-specific feeding trials whereby various terrestrial animals were fed suspect fish flesh, and a single incident in Madagascar in 1994, have resulted in the widespread acceptance that sharks may accumulate CTXs. This prompted a study to investigate original claims within the literature, as well as investigate CTX bioaccumulation in the muscle and liver of 22 individual sharks from nine species, across four locations along the east coast of Australia. Utilizing an updated ciguatoxin extraction method with HPLC-MS/MS, we were unable to detect P-CTX-1, P-CTX-2 or P-CTX-3, the three primary CTX congeners, in muscle or liver samples. We propose four theories to address this finding: (1) to date, methods have been optimized for teleost species and may not be appropriate for elasmobranchs, or the CTXs may be below the limit of detection; (2) CTX may be biotransformed into elasmobranch-specific congeners as a result of unique metabolic properties; (3) 22 individuals may be an inadequate sample size given the rare occurrence of high-order ciguatoxic organisms and potential for CTX depuration; and (4) the ephemeral nature and inconsistent toxin profiles of Gambierdiscus blooms may have undermined our classifications of certain areas as CTX hotspots. These results, in combination with the lack of clarity within the literature, suggest that ciguatoxin bioaccumulation in sharks remains elusive, and warrants further investigation to determine the dynamics of toxin production

  5. Grey Box Modelling of Hydrological Systems

    DEFF Research Database (Denmark)

    Thordarson, Fannar Ørn

    of two papers where the stochastic differential equation based model is used for sewer runoff from a drainage system. A simple model is used to describe a complex rainfall-runoff process in a catchment, but the stochastic part of the system is formulated to include the increasing uncertainty when...... rainwater flows through the system, as well as describe the lower limit of the uncertainty when the flow approaches zero. The first paper demonstrates in detail the grey box model and all related transformations required to obtain a feasible model for the sewer runoff. In the last paper this model is used......The main topic of the thesis is grey box modelling of hydrologic systems, as well as formulation and assessment of their embedded uncertainties. Grey box model is a combination of a white box model, a physically-based model that is traditionally formulated using deterministic ordinary differential...

  6. 75 FR 30483 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures; Amendment 3

    Science.gov (United States)

    2010-06-01

    ... and 635 Atlantic Highly Migratory Species; Atlantic Shark Management Measures; Amendment 3; Final Rule... and 635 [Docket No. 080519678-0217-02] RIN 0648-AW65 Atlantic Highly Migratory Species; Atlantic Shark... available to rebuild blacknose sharks and end overfishing of blacknose and shortfin mako sharks, consistent...

  7. 75 FR 8304 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2010-02-24

    ... Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and Identification... gear, and have also been issued shark or swordfish limited access permits. Additional free workshops... Coastal Highway, Ocean City, MD 21842. Atlantic Shark Identification Workshop Since January 1, 2007, shark...

  8. 77 FR 61562 - Atlantic Highly Migratory Species; 2013 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2012-10-10

    .... 120706221-2481-01] RIN 0648-XC106 Atlantic Highly Migratory Species; 2013 Atlantic Shark Commercial Fishing... establish opening dates and adjust quotas for the 2013 fishing season for the Atlantic commercial shark... the 2011 and 2012 Atlantic commercial shark fishing seasons. We propose to keep the porbeagle shark...

  9. 78 FR 25685 - Magnuson-Stevens Act Provisions; Implementation of the Shark Conservation Act of 2010

    Science.gov (United States)

    2013-05-02

    .... 111014628-3329-01] RIN 0648-BB54 Magnuson-Stevens Act Provisions; Implementation of the Shark Conservation... implement the provisions of the Shark Conservation Act of 2010 (SCA) and prohibit any person from removing any of the fins of a shark at sea, possessing shark fins on board a fishing vessel unless they are...

  10. 75 FR 67251 - Atlantic Highly Migratory Species; Inseason Action To Close the Commercial Blacknose Shark and...

    Science.gov (United States)

    2010-11-02

    ...-XZ95 Atlantic Highly Migratory Species; Inseason Action To Close the Commercial Blacknose Shark and Non-Blacknose Small Coastal Shark Fisheries AGENCY: National Marine Fisheries Service (NMFS), National Oceanic...: NMFS is closing the commercial blacknose shark and non- blacknose small coastal shark (SCS) fisheries...

  11. Grey literature in library and information studies

    CERN Document Server

    Schopfel, Joachim

    2010-01-01

    The further rise of electronic publishing has come to change the scale and diversity of grey literature facing librarians and other information practitioners. This compiled work brings together research and authorship over the past decade dealing with both the supply and demand sides of grey literature. While this book is written with students and instructors of Colleges and Schools of Library and Information Science in mind, it likewise serves as a reader for information professionals working in any and all like knowledge-based communities

  12. Interacting with wildlife tourism increases activity of white sharks.

    Science.gov (United States)

    Huveneers, Charlie; Watanabe, Yuuki Y; Payne, Nicholas L; Semmens, Jayson M

    2018-01-01

    Anthropogenic activities are dramatically changing marine ecosystems. Wildlife tourism is one of the fastest growing sectors of the tourism industry and has the potential to modify the natural environment and behaviour of the species it targets. Here, we used a novel method to assess the effects of wildlife tourism on the activity of white sharks ( Carcharodon carcharias ). High frequency three-axis acceleration loggers were deployed on ten white sharks for a total of ~9 days. A combination of multivariate and univariate analysis revealed that the increased number of strong accelerations and vertical movements when sharks are interacting with cage-diving operators result in an overall dynamic body acceleration (ODBA) ~61% higher compared with other times when sharks are present in the area where cage-diving occurs. Since ODBA is considered a proxy of metabolic rate, interacting with cage-divers is probably more costly than are normal behaviours of white sharks at the Neptune Islands. However, the overall impact of cage-diving might be small if interactions with individual sharks are infrequent. This study suggests wildlife tourism changes the instantaneous activity levels of white sharks, and calls for an understanding of the frequency of shark-tourism interactions to appreciate the net impact of ecotourism on this species' fitness.

  13. Mercury content of shark from south-western Australian waters

    Energy Technology Data Exchange (ETDEWEB)

    Caputi, N.; Edmonds, J.S.; Heald, D.I.

    1979-11-01

    Muscle samples from four species of commercially sought sharks off the Western Australia coast were analyzed for total mercury. While substantial amounts of mercury were accumulated by sharks, as by other marine fish, the lack of polluting industry on the coast indicates that such mercury levels probably are natural. Mercury concentrations generally increased with fish size. (4 graphs, 1 map, 8 references, 2 tables)

  14. Supercritical fluid chromatography of fish, shark and seal oils

    DEFF Research Database (Denmark)

    Borch-Jensen, Christina; Mollerup, Jørgen

    1996-01-01

    Various natural and treated fish, shark liver and seal oils have been analyzed by supercritical fluid chromatography (SFC) using a non-polar capillary column. The lipids are separated according to molecular mass. The lipid groups found included free fatty acids, cholesterol, squalene, vitamins, wax...... applications of SFC on fish, seal and shark liver oils are presented....

  15. Cephalopods in the diets of four shark species ( galeocerdo Cuvier ...

    African Journals Online (AJOL)

    The cephalopod components of the diets of four species of shark, tiger Galeocerdo cuvier, smooth hammerhead Sphyrna zygaena, scalloped hammerhead S. lewini and great hammerhead S. mokarran, were examined to reveal patterns of prey choice. Although these sharks were caught in the inshore gillnets used in ...

  16. Record Litter Size for the Bull Shark, Carcharhinus leucas (Muller ...

    African Journals Online (AJOL)

    On the morning of 25 September 2013, a large female bull shark, Carcharhinus leucas, was landed in Port Victoria, Seychelles. It had been caught on an anchored long line set the previous evening, within 100 m of the main fishing quay. The female exhibited an unusually large girth for this heavy-set species. The shark ...

  17. Age and growth of the common blacktip shark Carcharhinus ...

    African Journals Online (AJOL)

    Age and growth estimates from length-at-age data were produced for the common blacktip shark Carcharhinus limbatus from Indonesia. Back-calculation techniques were used due to a low sample size (n = 30), which was dominated by large, mature sharks. A multi-model approach incorporating Akaike's information ...

  18. Size distributions and sex ratios of sharks caught by Oman's ...

    African Journals Online (AJOL)

    Oman's fishery resources are exploited by artisanal and industrial fisheries, but the former accounts for almost 90% of landings. Within the artisanal fishery, sharks have traditionally been harvested for their flesh, but the development of a valuable export market for shark fin has led to increased utilisation of this resource, and ...

  19. White shark and other chondrichthyan interactions with the beach ...

    African Journals Online (AJOL)

    Public perception has been that an apparent increase in the nearshore occurrence of white sharks Carcharodon carcharias in False Bay, on the south coast of South Africa, can at least be partly attributed to beach-seine (treknet) operations attracting sharks into this coastal area. To assess the merit of these concerns, ...

  20. 33 CFR 117.751 - Shark River (South Channel).

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Shark River (South Channel). 117.751 Section 117.751 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.751 Shark River (South...

  1. Shark protection plan for the Dutch Caibbean EEZ

    NARCIS (Netherlands)

    Beek, van I.J.M.; Debrot, A.O.; Walker, P.A.; Kingma, I.

    2014-01-01

    Shark populations have steeply declined worldwide due to unsustainable overexploitation and in this the Caribbean region is no exception. Since the 1990s many initiatives have been developed to protect the most threatened species. Sharks play an important ecological role in tropical marine

  2. Great white sharks: the biology of Carcharodon carcharias

    National Research Council Canada - National Science Library

    Klimley, A.P; Ainley, D.G

    1996-01-01

    ... Morphology 37 Systematics of the Lamnidae and the Origination Time of Carcharodon carcharias Inferred from the Comparative Analysis of Mitochondrial DNA Sequences Size and Skeletal Anatomy of the Giant "Megatooth" Shark Carcharodon megalodon 55 Paleoecology of Fossil White Sharks 67 4. 5. 6. 7. 8. 11. Temperature, Swimming Depth, and Movements ...

  3. Bristled shark skin: a microgeometry for boundary layer control?

    International Nuclear Information System (INIS)

    Lang, A W; Hidalgo, P; Westcott, M; Motta, P

    2008-01-01

    There exists evidence that some fast-swimming shark species may have the ability to bristle their scales during fast swimming. Experimental work using a water tunnel facility has been performed to investigate the flow field over and within a bristled shark skin model submerged within a boundary layer to deduce the possible boundary layer control mechanisms being used by these fast-swimming sharks. Fluorescent dye flow visualization provides evidence of the formation of embedded cavity vortices within the scales. Digital particle image velocimetry (DPIV) data, used to evaluate the cavity vortex formation and boundary layer characteristics close to the surface, indicate increased momentum in the slip layer forming above the scales. This increase in flow velocity close to the shark's skin is indicative of boundary layer control mechanisms leading to separation control and possibly transition delay for the bristled shark skin microgeometry

  4. Bristled shark skin: a microgeometry for boundary layer control?

    Energy Technology Data Exchange (ETDEWEB)

    Lang, A W; Hidalgo, P; Westcott, M [Aerospace Engineering and Mechanics Department, University of Alabama, Box 870280, Tuscaloosa, AL 35487 (United States); Motta, P [Biology Department, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620 (United States)], E-mail: alang@eng.ua.edu

    2008-12-01

    There exists evidence that some fast-swimming shark species may have the ability to bristle their scales during fast swimming. Experimental work using a water tunnel facility has been performed to investigate the flow field over and within a bristled shark skin model submerged within a boundary layer to deduce the possible boundary layer control mechanisms being used by these fast-swimming sharks. Fluorescent dye flow visualization provides evidence of the formation of embedded cavity vortices within the scales. Digital particle image velocimetry (DPIV) data, used to evaluate the cavity vortex formation and boundary layer characteristics close to the surface, indicate increased momentum in the slip layer forming above the scales. This increase in flow velocity close to the shark's skin is indicative of boundary layer control mechanisms leading to separation control and possibly transition delay for the bristled shark skin microgeometry.

  5. "Sharks in Your Hands"--A Case Study on Effects of Teaching Strategies to Change Knowledge and Attitudes towards Sharks

    Science.gov (United States)

    Lee, Hung-Shan; Liu, Shiang-Yao; Yeh, Ting-Kuang

    2016-01-01

    This study was designed to exemplify how hands-on based teaching strategies enhanced students' knowledge and positive attitudes towards sharks. Hands-on activities for sharks' biological and morphological features were carried out. Eleven elementary school students from a remote area in Taiwan were recruited and assigned to the hands-on condition.…

  6. Biomimetic shark skin: design, fabrication and hydrodynamic function.

    Science.gov (United States)

    Wen, Li; Weaver, James C; Lauder, George V

    2014-05-15

    Although the functional properties of shark skin have been of considerable interest to both biologists and engineers because of the complex hydrodynamic effects of surface roughness, no study to date has successfully fabricated a flexible biomimetic shark skin that allows detailed study of hydrodynamic function. We present the first study of the design, fabrication and hydrodynamic testing of a synthetic, flexible, shark skin membrane. A three-dimensional (3D) model of shark skin denticles was constructed using micro-CT imaging of the skin of the shortfin mako (Isurus oxyrinchus). Using 3D printing, thousands of rigid synthetic shark denticles were placed on flexible membranes in a controlled, linear-arrayed pattern. This flexible 3D printed shark skin model was then tested in water using a robotic flapping device that allowed us to either hold the models in a stationary position or move them dynamically at their self-propelled swimming speed. Compared with a smooth control model without denticles, the 3D printed shark skin showed increased swimming speed with reduced energy consumption under certain motion programs. For example, at a heave frequency of 1.5 Hz and an amplitude of ± 1 cm, swimming speed increased by 6.6% and the energy cost-of-transport was reduced by 5.9%. In addition, a leading-edge vortex with greater vorticity than the smooth control was generated by the 3D printed shark skin, which may explain the increased swimming speeds. The ability to fabricate synthetic biomimetic shark skin opens up a wide array of possible manipulations of surface roughness parameters, and the ability to examine the hydrodynamic consequences of diverse skin denticle shapes present in different shark species. © 2014. Published by The Company of Biologists Ltd.

  7. Grey Literature Between Tradition and Innovation: Is There a Continuum?

    OpenAIRE

    Pardelli, Gabriella; Goggi, Sara; Sassi, Manuela

    2012-01-01

    This study wants to explore ways of social media communication for Grey Literature. In particular it describes the role of social media in relation with traditional channels and how social media applications can be used for Grey.

  8. Tularemia without lesions in grey tree squirrels: A diagnostic challenge

    Science.gov (United States)

    Fifteen cases of Francisella tularenesis infection (tularemia) were identified in western grey (Sciurus griseus) and eastern grey (Sciurus carolinesis) squirrels submitted to the Washington Animal Disease Diagnostic Laboratory between 2008 and 2011. All of the squirrels originated in Washington stat...

  9. How Close is too Close? The Effect of a Non-Lethal Electric Shark Deterrent on White Shark Behaviour.

    Science.gov (United States)

    Kempster, Ryan M; Egeberg, Channing A; Hart, Nathan S; Ryan, Laura; Chapuis, Lucille; Kerr, Caroline C; Schmidt, Carl; Huveneers, Charlie; Gennari, Enrico; Yopak, Kara E; Meeuwig, Jessica J; Collin, Shaun P

    2016-01-01

    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 studies. Therefore, there is a clear need for thorough testing of commercially available shark deterrents to provide the public with recommendations of their effectiveness. Using a modified stereo-camera system, we quantified behavioural interactions between white sharks (Carcharodon carcharias) and a baited target in the presence of a commercially available, personal electric shark deterrent (Shark Shield Freedom7™). The stereo-camera system enabled an accurate assessment of the behavioural responses of C. carcharias when encountering a non-lethal electric field many times stronger than what they would naturally experience. Upon their first observed encounter, all C. carcharias were repelled at a mean (± std. error) proximity of 131 (± 10.3) cm, which corresponded to a mean voltage gradient of 9.7 (± 0.9) V/m. With each subsequent encounter, their proximity decreased by an average of 11.6 cm, which corresponded to an increase in tolerance to the electric field by an average of 2.6 (± 0.5) V/m per encounter. Despite the increase in tolerance, sharks continued to be deterred from interacting for the duration of each trial when in the presence of an active Shark Shield™. Furthermore, the findings provide no support to the theory that electric deterrents attract sharks. The results of this study provide quantitative evidence of the effectiveness of a non-lethal electric shark deterrent, its influence on the behaviour of C. carcharias, and an accurate method for testing

  10. How Close is too Close? The Effect of a Non-Lethal Electric Shark Deterrent on White Shark Behaviour.

    Directory of Open Access Journals (Sweden)

    Ryan M Kempster

    Full Text Available 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 studies. Therefore, there is a clear need for thorough testing of commercially available shark deterrents to provide the public with recommendations of their effectiveness. Using a modified stereo-camera system, we quantified behavioural interactions between white sharks (Carcharodon carcharias and a baited target in the presence of a commercially available, personal electric shark deterrent (Shark Shield Freedom7™. The stereo-camera system enabled an accurate assessment of the behavioural responses of C. carcharias when encountering a non-lethal electric field many times stronger than what they would naturally experience. Upon their first observed encounter, all C. carcharias were repelled at a mean (± std. error proximity of 131 (± 10.3 cm, which corresponded to a mean voltage gradient of 9.7 (± 0.9 V/m. With each subsequent encounter, their proximity decreased by an average of 11.6 cm, which corresponded to an increase in tolerance to the electric field by an average of 2.6 (± 0.5 V/m per encounter. Despite the increase in tolerance, sharks continued to be deterred from interacting for the duration of each trial when in the presence of an active Shark Shield™. Furthermore, the findings provide no support to the theory that electric deterrents attract sharks. The results of this study provide quantitative evidence of the effectiveness of a non-lethal electric shark deterrent, its influence on the behaviour of C. carcharias, and an accurate

  11. Home range and food habits of Pacific reef sharks (primarily the gray reef shark, Carcharhinus amblyrhynchos)

    International Nuclear Information System (INIS)

    Nelson, D.R.; McKibben, J.N.; Tricas, T.C.; Cooksey, D.J.

    1979-01-01

    Progress is reported on the following studies: determining home range dimensions and stabilities by tracking sharks equipped with ultrasonic transmitters; telemetry instrumentation and techniques for applicability under Enewetak conditions; studies on social behavior, especially aggression toward divers, in relation to space utilization and group organization; and compilation of food-habit data from examination of stomach contents

  12. A recent shark radiation: molecular phylogeny, biogeography and speciation of wobbegong sharks (family: Orectolobidae).

    Science.gov (United States)

    Corrigan, Shannon; Beheregaray, Luciano B

    2009-07-01

    The elasmobranch fish are an ancient, evolutionarily successful, but under-researched vertebrate group, particularly in regard to their recent evolutionary history. Their lineage has survived four mass extinction events and most present day taxa are thought to be derived from Mesozoic forms. Here we present a molecular phylogenetic analysis of the family Orectolobidae that provides evidence for recent events of diversification in this shark group. Species interrelationships in Orectolobidae were reconstructed based on four mitochondrial and nuclear genes. In line with previous morphological work, our results do not support current taxonomic arrangements in Orectolobidae and indicate that a taxonomic revision of the family is warranted. We propose that the onset of diversification of orectolobid sharks is of Miocene age and occurred within the Indo-Australian region. Surprisingly, we also find evidence for a recent ( approximately last 2 million years) and rapid radiation of wobbegong sharks. Allopatric speciation followed by range expansion seems like the general most likely explanation to account for wobbegong relationships and distributions. We suggest that the evolution of this shark group was mostly influenced by two temporal scenarios of diversification. The oldest relates to major geological changes in the Indo-West Pacific associated with the Miocene collision of the Indo-Australian and Eurasian plates. The most recent scenario was influenced by changes in oceanography and the emergence of biogeographic barriers related to Pleistocene glacial cycles in Australian waters.

  13. TREATMENT OF GREY WATER USING CONSTRUCTED WETLAND SYSTEM

    OpenAIRE

    David Prashant Asirvadam; K. Dhivya Bharathi; P. Durairaj; M. Kaleeswaran; S. Abinaya

    2017-01-01

    The grey water is the waste water that is generated in the households or office buildings from streams without fecal contamination. Sources of grey water include water from sinks, showers, baths, washing machine or dish washers. As grey water contains fewer pathogens than domestic waste, it is generally safer to handle and easier to treat and reuse onsite for toilet flushing, landscape or crop irrigation. The removal of toxic content in grey water in this era is one of the most needed process...

  14. Assembling and testing of laboratory scale grey water treatment system

    OpenAIRE

    Harju, Vilhelmiina

    2010-01-01

    Grey water management and reuse is slowly gaining importance in the management of water resources. The benefits of well organized grey water management is that it offers a tool for coping with water scarcity and reduces the amount of pollution to enter the hydrological cycle. Grey water management aims on using treated grey water in applications which do not require drinking water quality. These non-potable reuse applications include industrial processes, irrigation, toilet flushing and lau...

  15. Grey-Box Modelling of Pharmacokinetic /Pharmacodynamic Systems

    DEFF Research Database (Denmark)

    Tornøe, Christoffer Wenzel; Jacobsen, Judith L.; Pedersen, Oluf

    2004-01-01

    Grey-box pharmacokinetic/pharmacodynamic (PK/PD) modelling is presented as a promising way of modelling PK/PD systems. The concept behind grey-box modelling is based on combining physiological knowledge along with information from data in the estimation of model parameters. Grey-box modelling...

  16. Searching for Grey Literature for Systematic Reviews: Challenges and Benefits

    Science.gov (United States)

    Mahood, Quenby; Van Eerd, Dwayne; Irvin, Emma

    2014-01-01

    There is ongoing interest in including grey literature in systematic reviews. Including grey literature can broaden the scope to more relevant studies, thereby providing a more complete view of available evidence. Searching for grey literature can be challenging despite greater access through the Internet, search engines and online bibliographic…

  17. Molecular cloning of the alpha subunit of complement component C8 (CpC8α) of whitespotted bamboo shark (Chiloscyllium plagiosum).

    Science.gov (United States)

    Wang, Ying; Zhang, Mengmeng; Wang, Conghui; Ye, Boping; Hua, Zichun

    2013-12-01

    Complement-mediated cytolysis is the important effect of immune response, which results from the assembly of terminal complement components (C5b-9). Among them, α subunit of C8 (C8α) is the first protein that traverses the lipid bilayer, and then initiates the recruitment of C9 molecules to form pore on target membranes. In this article, a full-length cDNA of C8α (CpC8α) is identified from the whitespotted bamboo shark (Chiloscyllium plagiosum) by RACE. The CpC8α cDNA is 2183 bp in length, encoding a protein of 591 amino acids. The deduced CpC8α exhibits 89%, 49% and 44% identity with nurse shark, frog and human orthologs, respectively. Sequence alignment indicates that the C8α is well conserved during the evolution process from sharks to mammals, with the same modular architecture as well as the identical cysteine composition in the mature protein. Phylogenetic analysis places CpC8α and nurse shark C8α in cartilaginous fish clade, in parallel with the teleost taxa, to form the C8α cluster with higher vertebrates. Hydrophobicity analysis also indicates a similar hydrophobicity of CpC8α to mammals. Finally, expression analysis revealed CpC8α transcripts were constitutively highly expressed in shark liver, with much less expression in other tissues. The well conserved structure and properties suggests an analogous function of CpC8α to mammalian C8α, though it remains to be confirmed by further study. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Immunoglobulin heavy chain exclusion in the shark.

    Directory of Open Access Journals (Sweden)

    Karolina Malecek

    2008-06-01

    Full Text Available The adaptive immune system depends on specific antigen receptors, immunoglobulins (Ig in B lymphocytes and T cell receptors (TCR in T lymphocytes. Adaptive responses to immune challenge are based on the expression of a single species of antigen receptor per cell; and in B cells, this is mediated in part by allelic exclusion at the Ig heavy (H chain locus. How allelic exclusion is regulated is unclear; we considered that sharks, the oldest vertebrates possessing the Ig/TCR-based immune system, would yield insights not previously approachable and reveal the primordial basis of the regulation of allelic exclusion. Sharks have an IgH locus organization consisting of 15-200 independently rearranging miniloci (VH-D1-D2-JH-Cmu, a gene organization that is considered ancestral to the tetrapod and bony fish IgH locus. We found that rearrangement takes place only within a minilocus, and the recombining gene segments are assembled simultaneously and randomly. Only one or few H chain genes were fully rearranged in each shark B cell, whereas the other loci retained their germline configuration. In contrast, most IgH were partially rearranged in every thymocyte (developing T cell examined, but no IgH transcripts were detected. The distinction between B and T cells in their IgH configurations and transcription reveals a heretofore unsuspected chromatin state permissive for rearrangement in precursor lymphocytes, and suggests that controlled limitation of B cell lineage-specific factors mediate regulated rearrangement and allelic exclusion. This regulation may be shared by higher vertebrates in which additional mechanistic and regulatory elements have evolved with their structurally complex IgH locus.

  19. Taxonomy Icon Data: white shark [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available white shark Carcharodon carcharias Chordata/Vertebrata/Pisciformes Carcharodon_carcharias_L.png Carcharo...don_carcharias_NL.png Carcharodon_carcharias_S.png Carcharodon_carcharias_NS.png http:/.../biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Carcharodon+carcharias&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Carcharo...don+carcharias&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Carcharo...don+carcharias&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Carcharodon+carcharias&t=NS ...

  20. Movement patterns of silvertip sharks ( Carcharhinus albimarginatus) on coral reefs

    Science.gov (United States)

    Espinoza, Mario; Heupel, Michelle. R.; Tobin, Andrew J.; Simpfendorfer, Colin A.

    2015-09-01

    Understanding how sharks use coral reefs is essential for assessing risk of exposure to fisheries, habitat loss, and climate change. Despite a wide Indo-Pacific distribution, little is known about the spatial ecology of silvertip sharks ( Carcharhinus albimarginatus), compromising the ability to effectively manage their populations. We examined the residency and movements of silvertip sharks in the central Great Barrier Reef (GBR). An array of 56 VR2W acoustic receivers was used to monitor shark movements on 17 semi-isolated reefs. Twenty-seven individuals tagged with acoustic transmitters were monitored from 70 to 731 d. Residency index to the study site ranged from 0.05 to 0.97, with a mean residency (±SD) of 0.57 ± 0.26, but most individuals were detected at or near their tagging reef. Clear seasonal patterns were apparent, with fewer individuals detected between September and February. A large proportion of the tagged population (>71 %) moved regularly between reefs. Silvertip sharks were detected less during daytime and exhibited a strong diel pattern in depth use, which may be a strategy for optimizing energetic budgets and foraging opportunities. This study provides the first detailed examination of the spatial ecology and behavior of silvertip sharks on coral reefs. Silvertip sharks remained resident at coral reef habitats over long periods, but our results also suggest this species may have more complex movement patterns and use larger areas of the GBR than common reef shark species. Our findings highlight the need to further understand the movement ecology of silvertip sharks at different spatial and temporal scales, which is critical for developing effective management approaches.

  1. Evaluation of appropriate technologies for grey water treatments and reuses.

    Science.gov (United States)

    Li, Fangyue; Wichmann, Knut; Otterpohl, Ralf

    2009-01-01

    As water is becoming a rare resource, the onsite reuse and recycling of grey water is practiced in many countries as a sustainable solution to reduce the overall urban water demand. However, the lack of appropriate water quality standards or guidelines has hampered the appropriate grey water reuses. Based on literature review, a non-potable urban grey water treatment and reuse scheme is proposed and the treatment alternatives for grey water reuse are evaluated according to the grey water characteristics, the proposed standards and economical feasibility.

  2. Evidence for Ig Light Chain Isotype Exclusion in Shark B Lymphocytes Suggests Ordered Mechanisms.

    Science.gov (United States)

    Iacoangeli, Anna; Lui, Anita; Haines, Ashley; Ohta, Yuko; Flajnik, Martin; Hsu, Ellen

    2017-09-01

    Unlike most vertebrates, the shark IgL gene organization precludes secondary rearrangements that delete self-reactive VJ rearranged genes. Nurse sharks express four L chain isotypes, κ, λ, σ, and σ-2, encoded by 35 functional minigenes or clusters. The sequence of gene activation/expression and receptor editing of these isotypes have not been studied. We therefore investigated the extent of isotypic exclusion in separated B cell subpopulations. Surface Ig (sIg)κ-expressing cells, isolated with mAb LK14 that recognizes Cκ, carry predominantly nonproductive rearrangements of other L chain isotypes. Conversely, after depletion with LK14, sIgM + cells contained largely nonproductive κ and enrichment for in-frame VJ of the others. Because some isotypic inclusion was observed at the mRNA level, expression in the BCR was examined. Functional λ mRNA was obtained, as expected, from the LK14-depleted population, but was also in sIgκ + splenocytes. Whereas λ somatic mutants from the depleted sample displayed evidence of positive selection, the λ genes in sIgκ + cells accumulated bystander mutations indicating a failure to express their products at the cell surface in association with the BCR H chain. In conclusion, a shark B cell expresses one L chain isotype at the surface and other isotypes as nonproductive VJ, sterile transcripts, or in-frame VJ whose products may not associate with the H chain. Based on the mRNA content found in the B cell subpopulations, an order of L chain gene activation is suggested as: σ-2 followed by κ, then σ and λ. Copyright © 2017 by The American Association of Immunologists, Inc.

  3. Dramatic increase in sea otter mortality from white sharks in California

    Science.gov (United States)

    Tinker, M. Tim; Hatfield, Brian B.; Harris, Michael D.; Ames, Jack A.

    2016-01-01

    Although southern sea otters (Enhydra lutris nereis) are not considered prey for white sharks (Carcharodon carcharias), sharks do nonetheless bite sea otters. We analyzed spatial and temporal trends in shark bites on sea otters in California, assessing the frequency of shark bite wounds in 1,870 carcasses collected since 1985. The proportion of stranded sea otters having shark bites has increased sharply since 2003, and white shark bites now account for >50% of recovered carcasses. The trend was most pronounced in the southern part of the range, from Estero Bay to Point Conception, where shark bite frequency has increased eightfold. Seasonal trends were also evident: most shark-bitten carcasses are recovered in late summer and fall; however, the period of elevated shark bite frequency has lengthened. The causes of these trends are unclear, but possible contributing factors include increased white shark abundance and/or changes in white shark behavior and distribution. In particular, the spatiotemporal patterns of shark-bitten sea otters match increases in pinniped populations, and the increased availability of marine mammal prey for white sharks may have led to more sharks spending more time in nearshore waters utilized by both sea otters and pinnipeds.

  4. Mercury in shark in western Australia: a preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Hancock, D.A.; Edmonds, J.S.; Edinger, J.J.

    1977-01-01

    Linear and curvilinear regressions relating mercury concentration and size were used in conjunction with catch data to estimate the average concentration in the three major shark species in the Western Australia fishery industry. The three species were whiskery (Furgaleus ventralis), bronze whaler (Carcharhinus obscurus) and gummy (Emissola antarctica) sharks. The averge mercury concentration for the 3 species was found to be approximately 0.75 ppM. The relevance of this to Public Health regulations was discussed and the need for information on consumption of shark stressed.

  5. Diet Composition and Trophic Ecology of Northeast Pacific Ocean Sharks.

    Science.gov (United States)

    Bizzarro, Joseph J; Carlisle, Aaron B; Smith, Wade D; Cortés, Enric

    Although there is a general perception of sharks as large pelagic, apex predators, most sharks are smaller, meso- and upper-trophic level predators that are associated with the seafloor. Among 73 shark species documented in the eastern North Pacific (ENP), less than half reach maximum lengths >200cm, and 78% occur in demersal or benthic regions of the continental shelf or slope. Most small (≤200cm) species (e.g., houndsharks) and demersal, nearshore juveniles of larger species (e.g., requiem sharks) consume small teleosts and decapod crustaceans, whereas large species in pelagic coastal and oceanic environments feed on large teleosts and squids. Several large, pelagic apex predator species occur in the ENP, but the largest species (i.e., Basking Shark, Whale Shark) consume zooplankton or small nekton. Size-based dietary variability is substantial for many species, and segregation of juvenile and adult foraging habitats also is common (e.g., Horn Shark, Shortfin Mako). Temporal dietary differences are most pronounced for temperate, nearshore species with wide size ranges, and least pronounced for smaller species in extreme latitudes and deep-water regions. Sympatric sharks often occupy various trophic positions, with resource overlap differing by space and time and some sharks serving as prey to other species. Most coastal species remain in the same general region over time and feed opportunistically on variable prey inputs (e.g., season migrations, spawning, or recruitment events), whereas pelagic, oceanic species actively seek hot spots of prey abundance that are spatiotemporally variable. The influence of sharks on ecosystem structure and regulation has been downplayed compared to that of large teleosts species with higher per capita consumption rates (e.g., tunas, billfishes). However, sharks also exert indirect influences on prey populations by causing behavioural changes that may result in restricted ranges and reduced fitness. Except for food web modelling

  6. A new high molecular weight immunoglobulin class from the carcharhine shark: implications for the properties of the primordial immunoglobulin.

    Science.gov (United States)

    Berstein, R M; Schluter, S F; Shen, S; Marchalonis, J J

    1996-04-16

    All immunoglobulins and T-cell receptors throughout phylogeny share regions of highly conserved amino acid sequence. To identify possible primitive immunoglobulins and immunoglobulin-like molecules, we utilized 3' RACE (rapid amplification of cDNA ends) and a highly conserved constant region consensus amino acid sequence to isolate a new immunoglobulin class from the sandbar shark Carcharhinus plumbeus. The immunoglobulin, termed IgW, in its secreted form consists of 782 amino acids and is expressed in both the thymus and the spleen. The molecule overall most closely resembles mu chains of the skate and human and a new putative antigen binding molecule isolated from the nurse shark (NAR). The full-length IgW chain has a variable region resembling human and shark heavy-chain (VH) sequences and a novel joining segment containing the WGXGT motif characteristic of H chains. However, unlike any other H-chain-type molecule, it contains six constant (C) domains. The first C domain contains the cysteine residue characteristic of C mu1 that would allow dimerization with a light (L) chain. The fourth and sixth domains also contain comparable cysteines that would enable dimerization with other H chains or homodimerization. Comparison of the sequences of IgW V and C domains shows homology greater than that found in comparisons among VH and C mu or VL, or CL thereby suggesting that IgW may retain features of the primordial immunoglobulin in evolution.

  7. A shark antibody heavy chain encoded by a nonsomatically rearranged VDJ is preferentially expressed in early development and is convergent with mammalian IgG.

    Science.gov (United States)

    Rumfelt, L L; Avila, D; Diaz, M; Bartl, S; McKinney, E C; Flajnik, M F

    2001-02-13

    In most vertebrate embryos and neonates studied to date unique antigen receptors (antibodies and T cell receptors) are expressed that possess a limited immune repertoire. We have isolated a subclass of IgM, IgM(1gj), from the nurse shark Ginglymostoma cirratum that is preferentially expressed in neonates. The variable (V) region gene encoding the heavy (H) chain underwent V-D-J rearrangement in germ cells ("germline-joined"). Such H chain V genes were discovered over 10 years ago in sharks but until now were not shown to be expressed at appreciable levels; we find expression of H(1gj) in primary and secondary lymphoid tissues early in life, but in adults only in primary lymphoid tissue, which is identified in this work as the epigonal organ. H(1gj) chain associates covalently with light (L) chains and is most similar in sequence to IgM H chains, but like mammalian IgG has three rather than the four IgM constant domains; deletion of the ancestral IgM C2 domain thus defines both IgG and IgM(1gj). Because sharks are the members of the oldest vertebrate class known to possess antibodies, unique or specialized antibodies expressed early in ontogeny in sharks and other vertebrates were likely present at the inception of the adaptive immune system.

  8. The future of grey-box fuzzing

    OpenAIRE

    Hjelt, Isak

    2017-01-01

    Society are becoming more dependent on software, and more artifacts are being connected to the Internet each day [31]. This makes the work of tracking down vulnerabilities in software a moral obligation for software developers. Since manual testing is expensive [7], automated bug finding techniques are attractive within the quality assurance field, since it can save companies a lot of money. This thesis summarizes the research of an automated bug finding technique called grey-box fuzzing, wit...

  9. A "Shark Encounter": Delayed Primary Closure and Prophylactic Antibiotic Treatment of a Great White Shark Bite.

    Science.gov (United States)

    Popa, Daniel; Van Hoesen, Karen

    2016-11-01

    Shark bites are rare but sensational injuries that are covered in the lay press but are not well described in the medical literature. We present the case of a 50-year-old man who sustained two deep puncture wounds to his thigh from a great white shark in the waters surrounding Isla de Guadalupe off the coast of Baja California, Mexico, during a caged SCUBA dive. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: We discuss our strategy of closing the wounds in a delayed primary fashion 24 hours after injury, our antibiotic choices, and the patient's course and review marine pathogens and appropriate antibiotic coverage. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Searching and synthesising 'grey literature' and 'grey information' in public health: critical reflections on three case studies.

    Science.gov (United States)

    Adams, Jean; Hillier-Brown, Frances C; Moore, Helen J; Lake, Amelia A; Araujo-Soares, Vera; White, Martin; Summerbell, Carolyn

    2016-09-29

    Grey literature includes a range of documents not controlled by commercial publishing organisations. This means that grey literature can be difficult to search and retrieve for evidence synthesis. Much knowledge and evidence in public health, and other fields, accumulates from innovation in practice. This knowledge may not even be of sufficient formality to meet the definition of grey literature. We term this knowledge 'grey information'. Grey information may be even harder to search for and retrieve than grey literature. On three previous occasions, we have attempted to systematically search for and synthesise public health grey literature and information-both to summarise the extent and nature of particular classes of interventions and to synthesise results of evaluations. Here, we briefly describe these three 'case studies' but focus on our post hoc critical reflections on searching for and synthesising grey literature and information garnered from our experiences of these case studies. We believe these reflections will be useful to future researchers working in this area. Issues discussed include search methods, searching efficiency, replicability of searches, data management, data extraction, assessing study 'quality', data synthesis, time and resources, and differentiating evidence synthesis from primary research. Information on applied public health research questions relating to the nature and range of public health interventions, as well as many evaluations of these interventions, may be predominantly, or only, held in grey literature and grey information. Evidence syntheses on these topics need, therefore, to embrace grey literature and information. Many typical systematic review methods for searching, appraising, managing, and synthesising the evidence base can be adapted for use with grey literature and information. Evidence synthesisers should carefully consider the opportunities and problems offered by including grey literature and information

  11. Review of the Freshwater Sharks of Iran (Family Carcharhinidae)

    OpenAIRE

    Brian W. Coad

    2015-01-01

    The systematics, morphology, distribution, biology, economic importance and conservation of the bull shark (Carcharhinus leucas) in Iran are described, the species is illustrated, and a bibliography on this fish in Iran is provided.

  12. Determination of methylmercury and inorganic mercury in shark fillets

    NARCIS (Netherlands)

    Krystek, Petra; Ritsema, Rob

    2004-01-01

    Three samples of deep-frozen shark fillets were analysed according to the following procedure: dissolution in tetramethylammonium hydroxide, derivatization/ethylation with sodium tetraethylborate, extraction into iso-octane and measurement with gas chromatography hyphenated to inductively coupled

  13. Atlantic Sharpnose and Blacknose Shark Congressional Supplemental Sampling

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Life history data were collected from Atlantic sharpnose and blacknose sharks during the Congressional Supplemental Program during 2011. Data collected include...

  14. Review of the Freshwater Sharks of Iran (Family Carcharhinidae

    Directory of Open Access Journals (Sweden)

    Brian W. Coad

    2015-07-01

    Full Text Available The systematics, morphology, distribution, biology, economic importance and conservation of the bull shark (Carcharhinus leucas in Iran are described, the species is illustrated, and a bibliography on this fish in Iran is provided.

  15. Diet of bonnethead shark in eastern Gulf of Mexico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To examine variation in diet and daily ration of the bonnethead, Sphyrna tiburo (Linnaeus, 1758), sharks were collected from three areas in the eastern Gulf of...

  16. Shark Attack Project - Marine Attack at Towed Hydrophone Arrays

    National Research Council Canada - National Science Library

    Kalmijn, Adrianus J

    2005-01-01

    The original objective of the SIO Marine Attack project was to identify the electric and magnetic fields causing sharks to inflict serious damage upon the towed hydrophone arrays of US Navy submarines...

  17. Predator Gut Isotopes - Characterizing ecosystem role of sharks

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This work uses white muscle tissues collected from sixgill and sevengill sharks to characterize the diet of each species. Tissues from prey species have also been...

  18. Cartilage (Bovine and Shark) (PDQ®)—Health Professional Version

    Science.gov (United States)

    Expert-reviewed information summary about the use of bovine and shark cartilage as a treatment for people with cancer. Note: The information in this summary is no longer being updated and is provided for reference purposes only.

  19. Cooperative Atlantic States Shark Pupping and Nursery (COASTSPAN)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Survey of inshore areas used by sharks for pupping and nurseries. Various locations have been surveyed, from the U.S. Virgin Islands to Massachusetts, most in...

  20. Morphology and evolution of the jaw suspension in lamniform sharks.

    Science.gov (United States)

    Wilga, C D

    2005-07-01

    The morphology of the jaw suspension and jaw protrusion mechanism in lamniform sharks is described and mapped onto a cladogram to investigate how changes in jaw suspension and protrusion have evolved. This has revealed that several evolutionary modifications in the musculoskeletal apparatus of the jaws have taken place among lamniform sharks. Galeomorph sharks (Carcharhiniformes, Lamniformes, Orectolobiformes, and Heterodontiformes) have paired ethmopalatine ligaments connecting the ethmoid process of the upper jaw to the ethmoid region of the cranium. Basal lamniform sharks also acquired a novel single palatonasal ligament connecting the symphysis of the upper jaw to the cranium mid-ventral to the nasal capsule. Sharks in the family Lamnidae subsequently lost the original paired ethmopalatine ligament while retaining the novel palatonasal ligament. Thus, basal lamniform taxa (Mitsukurina owstoni, Carcharius taurus, Alopias vulpinnis) have increased ligamentous support of the lateral region of the upper jaw while derived species (Lamnidae) have lost this lateral support but gained anterior support. In previous studies the morphology of the jaw suspension has been shown to play a major role in the mechanism of upper jaw protrusion in elasmobranchs. The preorbitalis is the primary muscle effecting upper jaw protrusion in squalean (sister group to galeomorphs) and carcharhiniform (sister group to lamniforms) sharks. The preorbitalis originates from the quadratomandibularis muscle and inserts onto the nasal capsule in squalean and carcharhiniform sharks. Carcharhiniform sharks have evolved a subdivided preorbitalis muscle with the new division inserting near the ethmoid process of the palatoquadrate (upper jaw). Alopid sharks have also independently evolved a partially subdivided preorbitalis with the new division inserting at the base of the ethmoid process and surrounding connective tissue. Lamnid sharks have retained the two preorbitalis divisions but have modified

  1. Diet of scalloped hammerhead shark in eastern Gulf of Mexico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Juvenile scalloped hammerhead sharks, Sphyrna lewini, were collected in northwest Florida to examine foraging ecology, bioenergetics, and trophic level (30-60 cm FL...

  2. Partitioning of body fluids in the Lake Nicaragua shark and three marine sharks.

    Science.gov (United States)

    THORSON, T B

    1962-11-09

    The relative volumes of major body fluids of freshwater and marine sharks are remarkably similar in spite of the differences in external medium and in osmotic pressure of body fluids. The small differences detected are in agreement with differences reported in comparisons of freshwater and marine teleosts: a slightly higher total water content and a smiller ratio of extracellular to intracellular fluids in freshwater forms.

  3. Movements of Blue Sharks (Prionace glauca) across Their Life History

    Science.gov (United States)

    Vandeperre, Frederic; Aires-da-Silva, Alexandre; Fontes, Jorge; Santos, Marco; Serrão Santos, Ricardo; Afonso, Pedro

    2014-01-01

    Spatial structuring and segregation by sex and size is considered to be an intrinsic attribute of shark populations. These spatial patterns remain poorly understood, particularly for oceanic species such as blue shark (Prionace glauca), despite its importance for the management and conservation of this highly migratory species. This study presents the results of a long-term electronic tagging experiment to investigate the migratory patterns of blue shark, to elucidate how these patterns change across its life history and to assess the existence of a nursery area in the central North Atlantic. Blue sharks belonging to different life stages (n = 34) were tracked for periods up to 952 days during which they moved extensively (up to an estimated 28.139 km), occupying large parts of the oceanic basin. Notwithstanding a large individual variability, there were pronounced differences in movements and space use across the species' life history. The study provides strong evidence for the existence of a discrete central North Atlantic nursery, where juveniles can reside for up to at least 2 years. In contrast with previously described nurseries of coastal and semi-pelagic sharks, this oceanic nursery is comparatively vast and open suggesting that shelter from predators is not its main function. Subsequently, male and female blue sharks spatially segregate. Females engage in seasonal latitudinal migrations until approaching maturity, when they undergo an ontogenic habitat shift towards tropical latitudes. In contrast, juvenile males generally expanded their range southward and apparently displayed a higher degree of behavioural polymorphism. These results provide important insights into the spatial ecology of pelagic sharks, with implications for the sustainable management of this heavily exploited shark, especially in the central North Atlantic where the presence of a nursery and the seasonal overlap and alternation of different life stages coincides with a high fishing

  4. Vertical movement patterns and ontogenetic niche expansion in the tiger shark, Galeocerdo cuvier.

    Science.gov (United States)

    Afonso, André S; Hazin, Fábio H V

    2015-01-01

    Sharks are top predators in many marine ecosystems and can impact community dynamics, yet many shark populations are undergoing severe declines primarily due to overfishing. Obtaining species-specific knowledge on shark spatial ecology is important to implement adequate management strategies for the effective conservation of these taxa. This is particularly relevant concerning highly-mobile species that use wide home ranges comprising coastal and oceanic habitats, such as tiger sharks, Galeocerdo cuvier. We deployed satellite tags in 20 juvenile tiger sharks off northeastern Brazil to assess the effect of intrinsic and extrinsic factors on depth and temperature usage. Sharks were tracked for a total of 1184 d and used waters up to 1112 m in depth. The minimum temperature recorded equaled 4°C. All sharks had a clear preference for surface (sharks used mostly shallow (sharks spending considerably more time in surface (shark habitat was observed, with generalized linear models estimating a ~4-fold increase in maximum diving depth from 150- to 300-cm size-classes. The time spent in the upper 5 m of the water column did not vary ontogenetically but shark size was the most important factor explaining the utilization of deeper water layers. Young-of-the-year tiger sharks seem to associate with shallow, neritic habitats but they progressively move into deeper oceanic habitats as they grow larger. Such an early plasticity in habitat use could endow tiger sharks with access to previously unavailable prey, thus contributing to a wider ecological niche.

  5. Acoustic telemetry reveals cryptic residency of whale sharks

    KAUST Repository

    Cagua, Edgar F.

    2015-04-01

    Althoughwhale sharks (Rhincodon typus) have beendocumentedtomove thousands of kilometres, they are most frequently observed at a few predictable seasonal aggregation sites. The absence of sharks at the surface during visual surveys has led to the assumption that sharks disperse to places unknown during the long \\'off-seasons\\' at most of these locations. Here we compare 2 years of R. typus visual sighting records from Mafia Island in Tanzania to concurrent acoustic telemetry of tagged individuals. Sightings revealed a clear seasonal pattern with a peak between October and February and no sharks observed at other times. By contrast, acoustic telemetry demonstrated yearround residency of R. typus. The sharks use a different habitat in the offseason, swimming deeper and further away from shore, presumably in response to prey distributions. This behavioural change reduces the sharks\\' visibility, giving the false impression that they have left the area.We demonstrate, for the first timeto our knowledge, year-roundresidencyofunprovisioned, individual R. typus at an aggregation site, and highlight the importance of using multiple techniques to study the movement ecology of marine megafauna. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  6. Olfaction Contributes to Pelagic Navigation in a Coastal Shark.

    Science.gov (United States)

    Nosal, Andrew P; Chao, Yi; Farrara, John D; Chai, Fei; Hastings, Philip A

    2016-01-01

    How animals navigate the constantly moving and visually uniform pelagic realm, often along straight paths between distant sites, is an enduring mystery. The mechanisms enabling pelagic navigation in cartilaginous fishes are particularly understudied. We used shoreward navigation by leopard sharks (Triakis semifasciata) as a model system to test whether olfaction contributes to pelagic navigation. Leopard sharks were captured alongshore, transported 9 km offshore, released, and acoustically tracked for approximately 4 h each until the transmitter released. Eleven sharks were rendered anosmic (nares occluded with cotton wool soaked in petroleum jelly); fifteen were sham controls. Mean swimming depth was 28.7 m. On average, tracks of control sharks ended 62.6% closer to shore, following relatively straight paths that were significantly directed over spatial scales exceeding 1600 m. In contrast, tracks of anosmic sharks ended 37.2% closer to shore, following significantly more tortuous paths that approximated correlated random walks. These results held after swimming paths were adjusted for current drift. This is the first study to demonstrate experimentally that olfaction contributes to pelagic navigation in sharks, likely mediated by chemical gradients as has been hypothesized for birds. Given the similarities between the fluid three-dimensional chemical atmosphere and ocean, further research comparing swimming and flying animals may lead to a unifying paradigm explaining their extraordinary navigational abilities.

  7. Vertebral bomb radiocarbon suggests extreme longevity in white sharks.

    Science.gov (United States)

    Hamady, Li Ling; Natanson, Lisa J; Skomal, Gregory B; Thorrold, Simon R

    2014-01-01

    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 chronologies documenting the marine uptake of (14)C produced by atmospheric testing of thermonuclear devices to generate the first radiocarbon age estimates for adult white sharks. Age estimates were up to 40 years old for the largest female (fork length [FL]: 526 cm) and 73 years old for the largest male (FL: 493 cm). Our results dramatically extend the maximum age and longevity of white sharks compared to earlier studies, hint at possible sexual dimorphism in growth rates, and raise concerns that white shark populations are considerably more sensitive to human-induced mortality than previously thought.

  8. Acoustic telemetry reveals cryptic residency of whale sharks.

    Science.gov (United States)

    Cagua, E Fernando; Cochran, Jesse E M; Rohner, Christoph A; Prebble, Clare E M; Sinclair-Taylor, Tane H; Pierce, Simon J; Berumen, Michael L

    2015-04-01

    Although whale sharks (Rhincodon typus) have been documented to move thousands of kilometres, they are most frequently observed at a few predictable seasonal aggregation sites. The absence of sharks at the surface during visual surveys has led to the assumption that sharks disperse to places unknown during the long 'off-seasons' at most of these locations. Here we compare 2 years of R. typus visual sighting records from Mafia Island in Tanzania to concurrent acoustic telemetry of tagged individuals. Sightings revealed a clear seasonal pattern with a peak between October and February and no sharks observed at other times. By contrast, acoustic telemetry demonstrated year-round residency of R. typus. The sharks use a different habitat in the off-season, swimming deeper and further away from shore, presumably in response to prey distributions. This behavioural change reduces the sharks' visibility, giving the false impression that they have left the area. We demonstrate, for the first time to our knowledge, year-round residency of unprovisioned, individual R. typus at an aggregation site, and highlight the importance of using multiple techniques to study the movement ecology of marine megafauna. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  9. Shark recreational fisheries: Status, challenges, and research needs.

    Science.gov (United States)

    Gallagher, Austin J; Hammerschlag, Neil; Danylchuk, Andy J; Cooke, Steven J

    2017-05-01

    For centuries, the primary manner in which humans have interacted with sharks has been fishing. A combination of their slow-growing nature and high use-values have resulted in population declines for many species around the world, and to date the vast majority of fisheries-related work on sharks has focused on the commercial sector. Shark recreational fishing remains an overlooked area of research despite the fact that these practices are popular globally and could present challenges to their populations. Here we provide a topical overview of shark recreational fisheries, highlighting their history and current status. While recreational fishing can provide conservation benefits under certain circumstances, we focus our discourse on the relatively understudied, potentially detrimental impacts these activities may have on shark physiology, behavior, and fitness. We took this angle given the realized but potentially underestimated significance of recreational fishing for shark conservation management plans and stock assessments, in hopes of creating a dialogue around sustainability. We also present a series of broad and focused research questions and underpin areas of future research need to assist with the development of this emergent area of research.

  10. The sixgill shark Hexanchus griseus is one of the most common ...

    African Journals Online (AJOL)

    denise

    2002-11-01

    Pisces, Selachii) de Angola. Notas Cent. Biol. Aquat. Trop., Lisboa 32: 1–23. SPRINGER, S. 1967 — Social organization of shark populations. In Sharks, Skates, and Rays. Gilbert, P. W., Mathewson, R. F. and D. P. Rall (Eds).

  11. 76 FR 65673 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures; Correction

    Science.gov (United States)

    2011-10-24

    ... these shark stocks and end overfishing, as necessary. The notice provided an incorrect date for a...' intent to undertake rulemaking to rebuild and/or end overfishing of these Atlantic shark stocks and to...

  12. Acoustic Monitoring of a Previously Unstudied Whale Shark Aggregation in the Red Sea

    KAUST Repository

    Cochran, Jesse

    2012-01-01

    in the area and to inform local management. Continued study will add to the collective knowledge on Red Sea whale sharks, including the population dynamics within the region and how they interact with the global whale shark community.

  13. Software sensors based on the grey-box modelling approach

    DEFF Research Database (Denmark)

    Carstensen, J.; Harremoës, P.; Strube, Rune

    1996-01-01

    In recent years the grey-box modelling approach has been applied to wastewater transportation and treatment Grey-box models are characterized by the combination of deterministic and stochastic terms to form a model where all the parameters are statistically identifiable from the on......-box model for the specific dynamics is identified. Similarly, an on-line software sensor for detecting the occurrence of backwater phenomena can be developed by comparing the dynamics of a flow measurement with a nearby level measurement. For treatment plants it is found that grey-box models applied to on......-line measurements. With respect to the development of software sensors, the grey-box models possess two important features. Firstly, the on-line measurements can be filtered according to the grey-box model in order to remove noise deriving from the measuring equipment and controlling devices. Secondly, the grey...

  14. Multiattribute Grey Target Decision Method Based on Soft Set Theory

    Directory of Open Access Journals (Sweden)

    Xia Wang

    2014-01-01

    Full Text Available With respect to the Multiattribute decision-making problems in which the evaluation attribute sets are different and the evaluating values of alternatives are interval grey numbers, a multiattribute grey target decision-making method in which the attribute sets are different was proposed. The concept of grey soft set was defined, and its “AND” operation was assigned by combining the intersection operation of grey number. The expression approach of new grey soft set of attribute sets considering by all decision makers were gained by applying the “AND” operation of grey soft set, and the weights of synthesis attribute were proved. The alternatives were ranked according to the size of distance of bull’s eyes of each alternative under synthetic attribute sets. The green supplier selection was illustrated to demonstrate the effectiveness of proposed model.

  15. Eocene squalomorph sharks (Chondrichthyes, Elasmobranchii) from Antarctica

    Science.gov (United States)

    Engelbrecht, Andrea; Mörs, Thomas; Reguero, Marcelo A.; Kriwet, Jürgen

    2017-10-01

    Rare remains of predominantly deep-water sharks of the families Hexanchidae, Squalidae, Dalatiidae, Centrophoridae, and Squatinidae are described from the Eocene La Meseta Formation, Seymour Island, Antarctic Peninsula, which has yielded the most abundant chondrichthyan assemblage from the Southern Hemisphere to date. Previously described representatives of Hexanchus sp., Squalus weltoni, Squalus woodburnei, Centrophorus sp., and Squatina sp. are confirmed and dental variations are documented. Although the teeth of Squatina sp. differ from other Palaeogene squatinid species, we refrain from introducing a new species. A new dalatiid taxon, Eodalatias austrinalis gen. et sp. nov. is described. This new material not only increases the diversity of Eocene Antarctic elasmobranchs but also allows assuming that favourable deep-water habitats were available in the Eocene Antarctic Ocean off Antarctica in the Eocene. The occurrences of deep-water inhabitants in shallow, near-coastal waters of the Antarctic Peninsula agrees well with extant distribution patterns.

  16. Eocene squalomorph sharks (Chondrichthyes, Elasmobranchii) from Antarctica.

    Science.gov (United States)

    Engelbrecht, Andrea; Mörs, Thomas; Reguero, Marcelo A; Kriwet, Jürgen

    2017-10-01

    Rare remains of predominantly deep-water sharks of the families Hexanchidae, Squalidae, Dalatiidae, Centrophoridae, and Squatinidae are described from the Eocene La Meseta Formation, Seymour Island, Antarctic Peninsula, which has yielded the most abundant chondrichthyan assemblage from the Southern Hemisphere to date. Previously described representatives of Hexanchus sp., Squalus weltoni , Squalus woodburnei , Centrophorus sp., and Squatina sp. are confirmed and dental variations are documented. Although the teeth of Squatina sp. differ from other Palaeogene squatinid species, we refrain from introducing a new species. A new dalatiid taxon, Eodalatias austrinalis gen. et sp. nov. is described. This new material not only increases the diversity of Eocene Antarctic elasmobranchs but also allows assuming that favourable deep-water habitats were available in the Eocene Antarctic Ocean off Antarctica in the Eocene. The occurrences of deep-water inhabitants in shallow, near-coastal waters of the Antarctic Peninsula agrees well with extant distribution patterns.

  17. Refining mortality estimates in shark demographic analyses: a Bayesian inverse matrix approach.

    Science.gov (United States)

    Smart, Jonathan J; Punt, André E; White, William T; Simpfendorfer, Colin A

    2018-01-18

    Leslie matrix models are an important analysis tool in conservation biology that are applied to a diversity of taxa. The standard approach estimates the finite rate of population growth (λ) from a set of vital rates. In some instances, an estimate of λ is available, but the vital rates are poorly understood and can be solved for using an inverse matrix approach. However, these approaches are rarely attempted due to prerequisites of information on the structure of age or stage classes. This study addressed this issue by using a combination of Monte Carlo simulations and the sample-importance-resampling (SIR) algorithm to solve the inverse matrix problem without data on population structure. This approach was applied to the grey reef shark (Carcharhinus amblyrhynchos) from the Great Barrier Reef (GBR) in Australia to determine the demography of this population. Additionally, these outputs were applied to another heavily fished population from Papua New Guinea (PNG) that requires estimates of λ for fisheries management. The SIR analysis determined that natural mortality (M) and total mortality (Z) based on indirect methods have previously been overestimated for C. amblyrhynchos, leading to an underestimated λ. The updated Z distributions determined using SIR provided λ estimates that matched an empirical λ for the GBR population and corrected obvious error in the demographic parameters for the PNG population. This approach provides opportunity for the inverse matrix approach to be applied more broadly to situations where information on population structure is lacking. © 2018 by the Ecological Society of America.

  18. Peering through the Review Process: Towards Transparency in Grey Literature

    OpenAIRE

    Farace, Dominic

    2010-01-01

    Now that grey literature is readily catalogued, referenced, cited, and openly accessible to subject based communities as well as net users, the claims that grey literature is unpublished or non-published have sufficiently been put to rest. However, now that grey literature has met these former challenges and entered mainstream publishing, it requires in the spirit of science to have a system in place for the quality control of its content. This new challenge has recently been spurred by the I...

  19. Long-Term Changes in Species Composition and Relative Abundances of Sharks at a Provisioning Site

    OpenAIRE

    Brunnschweiler, Juerg M.; Abrantes, Kátya G.; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-...

  20. Llinas’ Phase Reset Mechanism Delays the Onset of Chaos in Shark and Dolphin Wall Turbulence

    Science.gov (United States)

    2014-02-10

    the results of the modeling of chaos control by sharks . Skins of great white ,33 Atlantic sharpnose,36 and tiger shark37 dermal denticles (dd), with...13. c: Dermal denticles (diamond-shaped scales) of great white shark ; depending on species, there may be three to six riblets per scale (five to...Denticles of Great White Shark ," Electron Microscope Unit, University of Cape Town, Smithsonian Museum of Natural History, http://ocean.si.edu/ocean

  1. Grey('s) Identity: Complications of Learning and Becoming in a Popular Television Show

    Science.gov (United States)

    Jubas, Kaela

    2013-01-01

    In this article, the author outlines an analysis of the American show "Grey's Anatomy" as an example of how popular culture represents identity and the process of professional identity construction in a medical workplace, particularly the surgical service of a large urban hospital. In discussing identity, she connects professional identity to…

  2. Current status and a short history of grey literature. Focusing on the international conference on grey literature

    International Nuclear Information System (INIS)

    Ikeda, Kiyoshi

    2010-01-01

    'Grey literature' is a loosely defined term whose application is rather complex, but it is also an important source of information for academic researchers. Today, the spread of the Internet has led to changes not only in the circulation but also in the role and definition of 'grey literature'. This article therefore presents a short history of the definition of 'grey literature', with central focus on topics discussed by the International Conference on Grey Literature. After this, the current status and future prospects of 'grey literature' in the digital society are described. Finally, the article introduces the JAEA Library's activities on 'grey literature', particularly the acquisition of proceedings and the editing and dissemination of the JAEA Reports (technical reports of JAEA). (author)

  3. Grey Hair Evlsion Technique For Evaluating the Effect of Drugs For the Treatment of Premature Grey Hairs

    Directory of Open Access Journals (Sweden)

    J S Pasricha

    1985-01-01

    Full Text Available An improved method for evaluating the effect of treatment for premature grey hairs is described. The method consists of pulling out all the grey hairs in a patient and counting the number removed. Simultaneously, the converted hairs are also snipped at the grey-black junction and counted. After a gap of 3 months, the survey is repeated to count the number of hairs which have regrowing as grey hairs, the hairs which have become grey and also the hairs which have got converted into black during this period. Such surveys are repeated at 3 months intervals over a period of several years to see the progress of greying of hair in an individual and to evaluate the effect of various therapeutic procedures.

  4. 78 FR 24148 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2013-04-24

    ... declared that the status of the dusky shark stock is still overfished and still experiencing overfishing (i... rebuilding and ending overfishing of dusky sharks. This EIS would assess the potential effects on the human environment of action to rebuild and end overfishing of the dusky shark stock, consistent with the Magnuson...

  5. Sharks caught in the protective gill nets off KwaZulu-Natal, South ...

    African Journals Online (AJOL)

    Between 1978 and 1999, a total of 5 626 dusky sharks Carcharhinus obscurus, constituting 20% of the total shark catch, was caught in the protective nets off KwaZulu-Natal, South Africa. The mean annual catch was 256 sharks (SD = 107.5, range 129–571). There was no significant linear trend in catch rate with time.

  6. 77 FR 32036 - Atlantic Highly Migratory Species; Commercial Porbeagle Shark Fishery Closure

    Science.gov (United States)

    2012-05-31

    ...-XC044 Atlantic Highly Migratory Species; Commercial Porbeagle Shark Fishery Closure AGENCY: National...: Temporary rule; fishery closure. SUMMARY: NMFS is closing the commercial fishery for porbeagle sharks. This... available quota. DATES: The commercial porbeagle shark fishery is closed effective 11:30 p.m. local time May...

  7. 75 FR 53871 - Atlantic Highly Migratory Species; Inseason Action To Close the Commercial Porbeagle Shark Fishery

    Science.gov (United States)

    2010-09-02

    ... Porbeagle Shark Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric... for porbeagle sharks. This action is necessary because landings for the 2010 fishing season has reached at least 80 percent of the available quota. DATES: The commercial porbeagle shark fishery is...

  8. 78 FR 73500 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2013-12-06

    ... for Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and... Administration (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., February, and March of 2014. Certain fishermen and shark dealers are required to attend a workshop to meet...

  9. 78 FR 54456 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2013-09-04

    ... for Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and... Administration (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., November, and December of 2013. Certain fishermen and shark dealers are required to attend a workshop to...

  10. 76 FR 23935 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2011-04-29

    .... 110120049-1144-01] RIN 0648-BA69 Atlantic Highly Migratory Species; Atlantic Shark Management Measures... retention, transshipping, landing, storing, or selling of hammerhead sharks in the family Sphyrnidae (except for Sphyrna tiburo) and oceanic whitetip sharks (Carcharhinus longimanus) caught in association with...

  11. 77 FR 32950 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2012-06-04

    ... for Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and... Administration (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., August, and September of 2012. Certain fishermen and shark dealers are required to attend a workshop to...

  12. 75 FR 10217 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2010-03-05

    ... Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and Identification... (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: NMFS announces free Atlantic Shark... April, May, and June of 2010. Certain fishermen and shark dealers are required to attend a workshop to...

  13. 77 FR 12574 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2012-03-01

    ... for Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and... Administration (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., May, and June of 2012. Certain fishermen and shark dealers are required to attend a workshop to meet...

  14. 77 FR 55464 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2012-09-10

    ... for Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and... Administration (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., November, and December of 2012. Certain fishermen and shark dealers are required to attend a workshop to...

  15. 78 FR 52487 - Atlantic Highly Migratory Species; 2014 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2013-08-23

    .... 130402317-3707-01] RIN 0648-XC611 Atlantic Highly Migratory Species; 2014 Atlantic Shark Commercial Fishing... establish opening dates and adjust quotas for the 2014 fishing season for the Atlantic commercial shark... management measures to provide, to the extent practicable, fishing opportunities for commercial shark...

  16. 76 FR 11679 - Drawbridge Operation Regulation; Shark River (South Channel), Belmar, NJ

    Science.gov (United States)

    2011-03-03

    ... Operation Regulation; Shark River (South Channel), Belmar, NJ AGENCY: Coast Guard, DHS. ACTION: Notice of... temporary deviation from the regulations governing the operation of the S71 Bridge across Shark River (South... Bridge, a bascule lift drawbridge, across Shark River (South Channel), at mile 0.8, in Belmar, NJ, has a...

  17. 77 FR 73451 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2012-12-10

    ... for Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and... Administration (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., February, and March of 2013. Certain fishermen and shark dealers are required to attend a workshop to meet...

  18. 75 FR 44938 - Atlantic Coastal Fisheries Cooperative Management Act Provisions; Atlantic Coastal Shark Fishery

    Science.gov (United States)

    2010-07-30

    ... Coastal Fisheries Cooperative Management Act Provisions; Atlantic Coastal Shark Fishery AGENCY: National... moratorium on fishing for Atlantic coastal sharks in the State waters of New Jersey. NMFS canceled the... Fisheries Commission's (Commission) Interstate Fishery Management Plan for Atlantic Coastal Sharks (Coastal...

  19. 78 FR 15709 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2013-03-12

    ... for Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and... Administration (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., May, and June of 2013. Certain fishermen and shark dealers are required to attend a workshop to meet...

  20. 75 FR 57235 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2010-09-20

    .... 100825390-0431-01] RIN 0648-BA17 Atlantic Highly Migratory Species; Atlantic Shark Management Measures... on potential adjustments to the regulations governing the U.S. Atlantic shark fishery to address several specific issues currently affecting management of the shark fishery and to identify specific goals...

  1. 75 FR 74693 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2010-12-01

    ... for Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and... Administration (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., February, and March of 2011. Certain fishermen and shark dealers are required to attend a workshop to meet...

  2. 75 FR 50715 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures; Amendment 3

    Science.gov (United States)

    2010-08-17

    ... [Docket No. 080519678-0313-03] RIN 0648-AW65 Atlantic Highly Migratory Species; Atlantic Shark Management... for adjusting annual shark quotas based on over- and underharvests. This correction makes a change to...), instruction 12a revised 50 CFR 635.27 (b)(1)(i) through (v), relating to, among other things, pelagic shark...

  3. 77 FR 37647 - Atlantic Highly Migratory Species; Silky Shark Management Measures

    Science.gov (United States)

    2012-06-22

    .... 120416016-2151-01] RIN 0648-BB96 Atlantic Highly Migratory Species; Silky Shark Management Measures AGENCY..., transshipping, or landing of silky sharks (Carcharhinus falciformis) caught in association with ICCAT fisheries... sharks with bottom longline, gillnet, or handgear; nor would the rule affect recreational fishermen as...

  4. 76 FR 34209 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2011-06-13

    ... for Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and... Administration (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., August, and September of 2011. Certain fishermen and shark dealers are required to attend a workshop to...

  5. 77 FR 35357 - Atlantic Highly Migratory Species; Commercial Atlantic Region Non-Sandbar Large Coastal Shark...

    Science.gov (United States)

    2012-06-13

    ... Highly Migratory Species; Commercial Atlantic Region Non-Sandbar Large Coastal Shark Fishery Opening Date... commercial Atlantic region non-sandbar large coastal shark fishery. This action is necessary to inform... large coastal shark fishery will open on July 15, 2012. FOR FURTHER INFORMATION CONTACT: Karyl Brewster...

  6. Pilot study on behaviour of sharks around Saba using acoustic telemetry - Progress report 2014

    NARCIS (Netherlands)

    Winter, H.V.; Vink, D.; Beek, van I.J.M.

    2015-01-01

    Worldwide many shark populations are in strong decline mainly due to fisheries. Population status of sharks in the Caribbean is still poorly known. In order to be able to take effective measures to protect sharks, insight in their spatial behaviour during different life stages is required. Do marine

  7. 76 FR 72383 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2011-11-23

    ...-BA17 Atlantic Highly Migratory Species; Atlantic Shark Management Measures AGENCY: National Marine... plan (FMP) amendment that would consider catch shares for the Atlantic shark fisheries. The comment... potential catch shares programs in the Atlantic shark fisheries. Additionally, NMFS is extending the comment...

  8. 76 FR 53343 - Atlantic Highly Migratory Species; Commercial Porbeagle Shark Fishery Closure

    Science.gov (United States)

    2011-08-26

    ...-XA658 Atlantic Highly Migratory Species; Commercial Porbeagle Shark Fishery Closure AGENCY: National...: Temporary rule; fishery closure. SUMMARY: NMFS is closing the commercial fishery for porbeagle sharks. This... available quota. DATES: The commercial porbeagle shark fishery is closed effective 11:30 p.m. local time...

  9. 78 FR 54195 - Atlantic Highly Migratory Species; Atlantic Commercial Shark Fisheries

    Science.gov (United States)

    2013-09-03

    .... 110831548-3536-02] RIN 0648-XC836 Atlantic Highly Migratory Species; Atlantic Commercial Shark Fisheries...) dressed weight (dw) of non-blacknose small coastal shark (SCS) quota from the Atlantic region to the Gulf... Atlantic shark permitted vessels. DATES: The quota transfer is effective from September 2, 2013 until...

  10. 76 FR 77214 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2011-12-12

    ... for Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and... Administration (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., February, and March of 2012. Certain fishermen and shark dealers are required to attend a workshop to meet...

  11. 76 FR 67121 - Atlantic Highly Migratory Species; 2012 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2011-10-31

    .... 110913585-1625-01] RIN 0648-BB36 Atlantic Highly Migratory Species; 2012 Atlantic Shark Commercial Fishing... establish opening dates and adjust quotas for the 2012 fishing season for the Atlantic commercial shark... 2011 Atlantic commercial shark fishing seasons. In addition, NMFS proposes season openings based on...

  12. 75 FR 29991 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2010-05-28

    ... Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and Identification... (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., August, and September of 2010. Certain fishermen and shark dealers are required to attend a workshop to...

  13. 76 FR 11762 - Schedules for Atlantic Shark Identification Workshops and Protected Species Safe Handling...

    Science.gov (United States)

    2011-03-03

    ... for Atlantic Shark Identification Workshops and Protected Species Safe Handling, Release, and... Administration (NOAA), Commerce. ACTION: Notice of public workshops. SUMMARY: Free Atlantic Shark Identification..., May, and June of 2011. Certain fishermen and shark dealers are required to attend a workshop to meet...

  14. 75 FR 22103 - Atlantic Coastal Fisheries Cooperative Management Act Provisions; Atlantic Coastal Shark Fishery

    Science.gov (United States)

    2010-04-27

    ... species of sharks, including basking, great hammerhead, scalloped hammerhead, white, dusky, tiger, sand... Plan for Atlantic Coastal Sharks (Plan) and that the measures New Jersey has failed to implement and enforce are necessary for the conservation of the shark resource. This determination is consistent with...

  15. Impact of biology knowledge on the conservation and management of large pelagic sharks.

    Science.gov (United States)

    Yokoi, Hiroki; Ijima, Hirotaka; Ohshimo, Seiji; Yokawa, Kotaro

    2017-09-06

    Population growth rate, which depends on several biological parameters, is valuable information for the conservation and management of pelagic sharks, such as blue and shortfin mako sharks. However, reported biological parameters for estimating the population growth rates of these sharks differ by sex and display large variability. To estimate the appropriate population growth rate and clarify relationships between growth rate and relevant biological parameters, we developed a two-sex age-structured matrix population model and estimated the population growth rate using combinations of biological parameters. We addressed elasticity analysis and clarified the population growth rate sensitivity. For the blue shark, the estimated median population growth rate was 0.384 with a range of minimum and maximum values of 0.195-0.533, whereas those values of the shortfin mako shark were 0.102 and 0.007-0.318, respectively. The maturity age of male sharks had the largest impact for blue sharks, whereas that of female sharks had the largest impact for shortfin mako sharks. Hypotheses for the survival process of sharks also had a large impact on the population growth rate estimation. Both shark maturity age and survival rate were based on ageing validation data, indicating the importance of validating the quality of these data for the conservation and management of large pelagic sharks.

  16. 50 CFR 635.24 - Commercial retention limits for sharks and swordfish.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Commercial retention limits for sharks and... Management Measures § 635.24 Commercial retention limits for sharks and swordfish. The retention limits in this section are subject to the quotas and closure provisions in §§ 635.27 and 635.28. (a) Sharks. (1...

  17. Mercury accumulation in sharks from the coastal waters of southwest Florida.

    Science.gov (United States)

    Rumbold, Darren; Wasno, Robert; Hammerschlag, Neil; Volety, Aswani

    2014-10-01

    As large long-lived predators, sharks are particularly vulnerable to exposure to methylmercury biomagnified through the marine food web. Accordingly, nonlethal means were used to collect tissues for determining mercury (Hg) concentrations and stable isotopes of carbon (δ(13)C) and nitrogen (δ(15)N) from a total of 69 sharks, comprising 7 species, caught off Southwest Florida from May 2010 through June 2013. Species included blacknose (Carcharhinus acronotus), blacktip (C. limbatus), bull (C. leucas), great hammerhead (Sphyrna mokarran), lemon (Negaprion brevirostris), sharpnose (Rhizoprionodon terraenovae), and tiger sharks (Galeocerdo cuvier). The sharks contained Hg concentrations in their muscle tissues ranging from 0.19 mg/kg (wet-weight basis) in a tiger shark to 4.52 mg/kg in a blacktip shark. Individual differences in total length and δ(13)C explained much of the intraspecific variation in Hg concentrations in blacknose, blacktip, and sharpnose sharks, but similar patterns were not evident for Hg and δ(15)N. Interspecific differences in Hg concentration were evident with greater concentrations in slower-growing, mature blacktip sharks and lower concentrations in faster-growing, young tiger sharks than other species. These results are consistent with previous studies reporting age-dependent growth rate can be an important determinant of intraspecific and interspecific patterns in Hg accumulation. The Hg concentrations observed in these sharks, in particular the blacktip shark, also suggested that Hg may pose a threat to shark health and fitness.

  18. Ocean-wide tracking of pelagic sharks reveals extent of overlap with longline fishing hotspots.

    Science.gov (United States)

    Queiroz, Nuno; Humphries, Nicolas E; Mucientes, Gonzalo; Hammerschlag, Neil; Lima, Fernando P; Scales, Kylie L; Miller, Peter I; Sousa, Lara L; Seabra, Rui; Sims, David W

    2016-02-09

    Overfishing is arguably the greatest ecological threat facing the oceans, yet catches of many highly migratory fishes including oceanic sharks remain largely unregulated with poor monitoring and data reporting. Oceanic shark conservation is hampered by basic knowledge gaps about where sharks aggregate across population ranges and precisely where they overlap with fishers. Using satellite tracking data from six shark species across the North Atlantic, we show that pelagic sharks occupy predictable habitat hotspots of high space use. Movement modeling showed sharks preferred habitats characterized by strong sea surface-temperature gradients (fronts) over other available habitats. However, simultaneous Global Positioning System (GPS) tracking of the entire Spanish and Portuguese longline-vessel fishing fleets show an 80% overlap of fished areas with hotspots, potentially increasing shark susceptibility to fishing exploitation. Regions of high overlap between oceanic tagged sharks and longliners included the North Atlantic Current/Labrador Current convergence zone and the Mid-Atlantic Ridge southwest of the Azores. In these main regions, and subareas within them, shark/vessel co-occurrence was spatially and temporally persistent between years, highlighting how broadly the fishing exploitation efficiently "tracks" oceanic sharks within their space-use hotspots year-round. Given this intense focus of longliners on shark hotspots, our study argues the need for international catch limits for pelagic sharks and identifies a future role of combining fine-scale fish and vessel telemetry to inform the ocean-scale management of fisheries.

  19. Nurse stress at two different organizational settings in Alexandria

    Directory of Open Access Journals (Sweden)

    Ashraf AZ Zaghloul

    2009-04-01

    Full Text Available Ashraf AZ Zaghloul, Nagwa Y Abou El EneinDepartment of Health Administration and Behavioural Sciences, High Institute of Public Health, University of Alexandria, Alexandria, EgyptObjective: The objective of the study was to explore the difference in stress levels among nurses working at two different health care organizations and the determinants of nurse stress within each organization. Job stress is defined as the harmful emotional and physical reactions resulting from the interactions between the worker and her/his work environment where the demands of the job exceed the worker’s capabilities and resources.Methodology: A convenient sample of nurses in two hospitals in Alexandria; Shark Al Madina (n = 120 and Karmouz (n = 170 hospitals. All nurses present at the time of the study were approached to be included in the study. The response rate for Shark Al Madina hospital was 94% and for Karmouz hospital, 71%. Data collection took place using a nurse stress questionnaire previously developed and tested for validity and reliability to measure stress in clinical nursing practice. The 5% level of significance was used throughout the statistical analysis for all relevant tests.Results: The highest mean stress scores were the same for both hospitals. The dimension of coping with new situations was 2.7 ± 0.6 at Shark Al Madina hospital and was 2.5 ± 0.7 at Karmouz hospital while the dimension of job security was 2.7 ± 0.6 and 2.5 ± 0.7 at Shark Al Madina and Karmouz hospitals, respectively. Stepwise multiple regression for Shark Al Madina hospital model revealed workload (β = 1.38, security (β = 5.04, and shortage of support staff (β = 3.39. For the Karmouz hospital model, stepwise multiple regression revealed security (β = 4.78 and shortage of resources (β = 3.66.Conclusion: Stressors among nurses appear to be the same despite the differences in organizational or hierarchical structure where they work or the type of consumer they serve. It

  20. Access to Grey Content: An Analysis of Grey Literature based on Citation and Survey Data, A Follow-up Study

    OpenAIRE

    Farace, Dominic J. (GreyNet); Frantzen, Jerry (GreyNet); Boekhorst, Albert K. (UvA); Schöpfel, Joachim (INIST-CNRS); Stock, Christiane (INIST-CNRS); GreyNet, Grey Literature Network Service

    2005-01-01

    Grey literature, an area of interest to special librarians and information professionals, can be traced back a half-century. However, grey literature as a specialized field in information studies is less than a decade old. At GL'97 in Luxembourg, grey literature was redefined "as information produced on all levels of government, academics, business and industry in electronic and print formats not controlled by commercial publishers (i.e. where publishing is not the primary activity of the pro...

  1. Grey-grey separate spatial soliton pairs in a biased series two-photon centrosymmetric photorefractive crystals circuit

    International Nuclear Information System (INIS)

    Ji, Xuanmang; Wang, Jinlai; Jiang, Qichang; Liu, Jinsong

    2012-01-01

    Grey-grey separate spatial soliton pairs are predicted in a biased series circuit consisting of two centrosymmetric photorefractive (PR) crystals with the two-photon PR effect. The numerical results show that two grey solitons in a soliton pair can affect each other by the light-induced current. The effects of the intensity of solitary waves and gating lights on the normalized profiles and the dynamical evolutions of solitons are discussed.

  2. Laser photogrammetry improves size and demographic estimates for whale sharks

    Science.gov (United States)

    Richardson, Anthony J.; Prebble, Clare E.M.; Marshall, Andrea D.; Bennett, Michael B.; Weeks, Scarla J.; Cliff, Geremy; Wintner, Sabine P.; Pierce, Simon J.

    2015-01-01

    Whale sharks Rhincodon typus are globally threatened, but a lack of biological and demographic information hampers an accurate assessment of their vulnerability to further decline or capacity to recover. We used laser photogrammetry at two aggregation sites to obtain more accurate size estimates of free-swimming whale sharks compared to visual estimates, allowing improved estimates of biological parameters. Individual whale sharks ranged from 432–917 cm total length (TL) (mean ± SD = 673 ± 118.8 cm, N = 122) in southern Mozambique and from 420–990 cm TL (mean ± SD = 641 ± 133 cm, N = 46) in Tanzania. By combining measurements of stranded individuals with photogrammetry measurements of free-swimming sharks, we calculated length at 50% maturity for males in Mozambique at 916 cm TL. Repeat measurements of individual whale sharks measured over periods from 347–1,068 days yielded implausible growth rates, suggesting that the growth increment over this period was not large enough to be detected using laser photogrammetry, and that the method is best applied to estimating growth rates over longer (decadal) time periods. The sex ratio of both populations was biased towards males (74% in Mozambique, 89% in Tanzania), the majority of which were immature (98% in Mozambique, 94% in Tanzania). The population structure for these two aggregations was similar to most other documented whale shark aggregations around the world. Information on small (sharks, mature individuals, and females in this region is lacking, but necessary to inform conservation initiatives for this globally threatened species. PMID:25870776

  3. Shark Interactions With Directed and Incidental Fisheries in the Northeast Pacific Ocean: Historic and Current Encounters, and Challenges for Shark Conservation.

    Science.gov (United States)

    King, Jackie; McFarlane, Gordon A; Gertseva, Vladlena; Gasper, Jason; Matson, Sean; Tribuzio, Cindy A

    For over 100 years, sharks have been encountered, as either directed catch or incidental catch, in commercial fisheries throughout the Northeast Pacific Ocean. A long-standing directed fishery for North Pacific Spiny Dogfish (Squalus suckleyi) has occurred and dominated shark landings and discards. Other fisheries, mainly for shark livers, have historically targeted species including Bluntnose Sixgill Shark (Hexanchus griseus) and Tope Shark (Galeorhinus galeus). While incidental catches of numerous species have occurred historically, only recently have these encounters been reliably enumerated in commercial and recreational fisheries. In this chapter we present shark catch statistics (directed and incidental) for commercial and recreational fisheries from Canadian waters (off British Columbia), southern US waters (off California, Oregon, and Washington), and northern US waters (off Alaska). In total, 17 species of sharks have collectively been encountered in these waters. Fishery encounters present conservation challenges for shark management, namely, the need for accurate catch statistics, stock delineation, life history parameter estimates, and improved assessments methods for population status and trends. Improvements in management and conservation of shark populations will only come with the further development of sound science-based fishery management practices for both targeted and incidental shark fisheries. © 2017 Elsevier Ltd All rights reserved.

  4. On grey levels in random CAPTCHA generation

    Science.gov (United States)

    Newton, Fraser; Kouritzin, Michael A.

    2011-06-01

    A CAPTCHA is an automatically generated test designed to distinguish between humans and computer programs; specifically, they are designed to be easy for humans but difficult for computer programs to pass in order to prevent the abuse of resources by automated bots. They are commonly seen guarding webmail registration forms, online auction sites, and preventing brute force attacks on passwords. In the following, we address the question: How does adding a grey level to random CAPTCHA generation affect the utility of the CAPTCHA? We treat the problem of generating the random CAPTCHA as one of random field simulation: An initial state of background noise is evolved over time using Gibbs sampling and an efficient algorithm for generating correlated random variables. This approach has already been found to yield highly-readable yet difficult-to-crack CAPTCHAs. We detail how the requisite parameters for introducing grey levels are estimated and how we generate the random CAPTCHA. The resulting CAPTCHA will be evaluated in terms of human readability as well as its resistance to automated attacks in the forms of character segmentation and optical character recognition.

  5. Grey Rod Test in HANARO Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Choo, K. N.; Kim, B. G.; Kang, Y. H. (and others)

    2008-08-15

    Westinghouse/KAERI/KNF agreed to perform an irradiation test in the HANARO reactor to obtain irradiation data on the new grey rods that will be part of an AP1000 system. As a preliminary test, two samples containing pure Ag (Reference) and Ag-In-Cd materials provided by Westinghouse Electric Company (WEC) were inserted in a KNF irradiation capsule of 07M-13N. The specimens were irradiated for 95.19days (4 cycles) in the CT test hole of the HANARO of a 30MW thermal output to have a fast neutron fluence of 1.11x10{sup 21}(n/cm{sup 2}) (E>1.0MeV). This report provides all the test conditions and data obtained during the irradiation test of the grey rods in HANARO requested by Westinghouse. The test was prepared according to the meeting minutes (June 26, 2007) and the on-going subject test was stopped midway by the request of Westinghouse.

  6. Vulnerability of oceanic sharks as pelagic longline bycatch

    Directory of Open Access Journals (Sweden)

    A.J. Gallagher

    2014-08-01

    Full Text Available Bycatch (the unintentional catch of non-target species or sizes is consistently ranked as one of the greatest threats to marine fish populations; yet species-specific rates of bycatch survival are rarely considered in risk assessments. Regulations often require that bycatch of threatened species be released; but, if animals are already dead, their release serves no conservation purpose. We examined the survival of 12 shark species caught as bycatch in the US Atlantic pelagic longline fishery. Shark survival was evaluated in relation to fishery target (swordfish versus tuna and four operational, environmental, and biological variables to evaluate the underlying mechanisms affecting mortality. Survival estimates ranged from 33% (night shark to 97% (tiger shark with seven of the 12 species being significantly affected by at least one variable. We placed our survival results within a framework that assessed each species’ relative vulnerability by integrating survival estimates with reproductive potential and found that the bigeye thresher, dusky, night, and scalloped hammerhead shark exhibited the highest vulnerabilities to bycatch. We suggest that considering ecological and biological traits of species shows promise for designing effective conservation measures, whereas techniques that reduce fisheries interactions in the first place may be the best strategy for highly vulnerable species.

  7. Acoustic backscatter at a Red Sea whale shark aggregation site

    KAUST Repository

    Hozumi, Aya; Kaartvedt, Stein; Rø stad, Anders; Berumen, Michael L.; Cochran, Jesse E.M.; Jones, Burton

    2018-01-01

    An aggregation of sexually immature whale sharks occurs at a coastal submerged reef near the Saudi Arabian Red Sea coast each spring. We tested the hypothesis that these megaplanktivores become attracted to a prey biomass peak coinciding with their aggregation. Acoustic backscatter of the water column at 120 kHz and 333 kHz –a proxy for potential prey biomass –was continuously measured spanning the period prior to, during, and subsequent to the seasonal whale shark aggregations. No peak in acoustic backscatter was observed at the time of the aggregation. However, we observed a decrease in acoustic backscatter in the last days of deployment, which coincided the trailing end of whale shark season. Organisms forming the main scattering layer performed inverse diel vertical migration, with backscatter peaking at mid-depths during the day and in the deeper half of the water column at night. Target strength analyses suggested the backscatter was likely composed of fish larvae. Subsurface foraging behavior of the whale sharks within this aggregation has not been described, yet this study does not support the hypothesis that seasonal peaks in local whale shark abundance correspond to similar peaks in prey availability.

  8. Acoustic backscatter at a Red Sea whale shark aggregation site

    KAUST Repository

    Hozumi, Aya

    2018-03-28

    An aggregation of sexually immature whale sharks occurs at a coastal submerged reef near the Saudi Arabian Red Sea coast each spring. We tested the hypothesis that these megaplanktivores become attracted to a prey biomass peak coinciding with their aggregation. Acoustic backscatter of the water column at 120 kHz and 333 kHz –a proxy for potential prey biomass –was continuously measured spanning the period prior to, during, and subsequent to the seasonal whale shark aggregations. No peak in acoustic backscatter was observed at the time of the aggregation. However, we observed a decrease in acoustic backscatter in the last days of deployment, which coincided the trailing end of whale shark season. Organisms forming the main scattering layer performed inverse diel vertical migration, with backscatter peaking at mid-depths during the day and in the deeper half of the water column at night. Target strength analyses suggested the backscatter was likely composed of fish larvae. Subsurface foraging behavior of the whale sharks within this aggregation has not been described, yet this study does not support the hypothesis that seasonal peaks in local whale shark abundance correspond to similar peaks in prey availability.

  9. Introduction to Northeast Pacific Shark Biology, Ecology, and Conservation.

    Science.gov (United States)

    Lowry, Dayv; Larson, Shawn E

    Sharks are iconic, sometimes apex, predators found in every ocean and, as a result, they have featured prominently in the mythology, history, and fisheries of diverse human cultures around the world. Because of their regional significance to fisheries and ecological role as predators, and as a result of concern over long-term stability of their populations, there has been an increasing amount of work focused on shark conservation in recent decades. This volume highlights the biodiversity and biological attributes of, and conservation efforts targeted at, populations of sharks that reside in the Northeast Pacific Ocean bordering the west coast of the United States and Canada, one of the most economically and ecologically important oceanic regions in the world. A companion volume addresses details of fisheries and ecotourism in the same region, as well as delving into the relationship between captive husbandry of sharks and education/outreach efforts aimed at fostering a conservation mindset in the public at large. Together, these volumes provide readers a detailed backdrop against which to consider their own actions, and those of resource managers, academics, and educators, as they relate to the long-term conservation of sharks and their relatives. © 2017 Elsevier Ltd. All rights reserved.

  10. 78 FR 17183 - Information Collection: Grey Towers Visitor Comment Card

    Science.gov (United States)

    2013-03-20

    ... DEPARTMENT OF AGRICULTURE Forest Service Information Collection: Grey Towers Visitor Comment Card... request: (1) An extension from the Office of Management and Budget; and (2) to merge the currently approved information collection 0596- 0222, ``Grey Towers Visitor Comment Card'' with 0596-0226, ``Forest...

  11. Effect of titanium on the near eutectic grey iron

    DEFF Research Database (Denmark)

    Moumeni, Elham; Tiedje, Niels Skat; Hattel, Jesper Henri

    The effect of Titanium on the microstructure of grey iron was investigated experimentally in this work. Tensile test bars of grey cast iron of near eutectic alloys containing 0.01, 0.1, 0.26 and 0.35% Ti, respectively were made in green sand moulds. Chemical analysis, metallographic investigation...

  12. Grey scale, the 'crispening effect', and perceptual linearization

    NARCIS (Netherlands)

    Belaïd, N.; Martens, J.B.

    1998-01-01

    One way of optimizing a display is to maximize the number of distinguishable grey levels, which in turn is equivalent to perceptually linearizing the display. Perceptual linearization implies that equal steps in grey value evoke equal steps in brightness sensation. The key to perceptual

  13. Are Caribbean reef sharks, Carcharhinus perezi, able to perceive human body orientation?

    Science.gov (United States)

    Ritter, Erich K; Amin, Raid

    2014-05-01

    The present study examines the potential capability of Caribbean reef sharks to perceive human body orientation, as well as discussing the sharks' swimming patterns in a person's vicinity. A standardized video method was used to record the scenario of single SCUBA divers kneeling in the sand and the approach patterns of sharks, combined with a control group of two divers kneeling back-to-back. When approaching a single test-subject, significantly more sharks preferred to swim outside the person's field of vision. The results suggest that these sharks are able to identify human body orientation, but the mechanisms used and factors affecting nearest distance of approach remain unclear.

  14. Nurse stress at two different organizational settings in Alexandria.

    Science.gov (United States)

    Zaghloul, Ashraf Az; Abou El Enein, Nagwa Y

    2009-04-15

    The objective of the study was to explore the difference in stress levels among nurses working at two different health care organizations and the determinants of nurse stress within each organization. Job stress is defined as the harmful emotional and physical reactions resulting from the interactions between the worker and her/his work environment where the demands of the job exceed the worker's capabilities and resources. A convenient sample of nurses in two hospitals in Alexandria; Shark Al Madina (n = 120) and Karmouz (n = 170) hospitals. All nurses present at the time of the study were approached to be included in the study. The response rate for Shark Al Madina hospital was 94% and for Karmouz hospital, 71%. Data collection took place using a nurse stress questionnaire previously developed and tested for validity and reliability to measure stress in clinical nursing practice. The 5% level of significance was used throughout the statistical analysis for all relevant tests. The highest mean stress scores were the same for both hospitals. The dimension of coping with new situations was 2.7 ± 0.6 at Shark Al Madina hospital and was 2.5 ± 0.7 at Karmouz hospital while the dimension of job security was 2.7 ± 0.6 and 2.5 ± 0.7 at Shark Al Madina and Karmouz hospitals, respectively. Stepwise multiple regression for Shark Al Madina hospital model revealed workload (β = 1.38), security (β = 5.04), and shortage of support staff (β = 3.39). For the Karmouz hospital model, stepwise multiple regression revealed security (β = 4.78) and shortage of resources (β = 3.66). Stressors among nurses appear to be the same despite the differences in organizational or hierarchical structure where they work or the type of consumer they serve. It is important to reduce occupational stress in nurses and to strengthen their coping resources to prevent nurse burnout. This could be achieved with job redesign, modification of shift work systems, and by offering occupational health

  15. 76 FR 41753 - Sierra National Forest, Bass Lake Ranger District, California, Grey's Mountain Ecosystem...

    Science.gov (United States)

    2011-07-15

    ..., California, Grey's Mountain Ecosystem Restoration Project AGENCY: Forest Service, USDA. ACTION: Notice of...: Background Information: The Grey's Mountain Ecosystem Restoration Project (Madera County, California) lies... vegetation. Currently, vegetation within the Grey's Mountain Ecosystem Restoration Project has changed from...

  16. Alternative Axiomatic Characterizations of the Grey Shapley Value

    Directory of Open Access Journals (Sweden)

    Sirma Zeynep Alparslan Gok

    2014-05-01

    Full Text Available The Shapley value, one of the most common solution concepts of cooperative game theory is defined and axiomatically characterized in different game-theoretic models. Certainly, the Shapley value can be used in interesting sharing cost/reward problems in the Operations Research area such as connection, routing, scheduling, production and inventory situations. In this paper, we focus on the Shapley value for cooperative games, where the set of players is finite and the coalition values are interval grey numbers. The central question in this paper is how to characterize the grey Shapley value. In this context, we present two alternative axiomatic characterizations. First, we characterize the grey Shapley value using the properties of efficiency, symmetry and strong monotonicity. Second, we characterize the grey Shapley value by using the grey dividends.

  17. Grey seal predation on forage fish in the Baltic Sea

    DEFF Research Database (Denmark)

    Eero, Aro; Neuenfeldt, Stefan; Aho, Teija

    The mean annual growth rate of grey seal stock in the Baltic has been on average 7.5% annually during the last decade. In 2010, a total of approximately 23 100 grey seals were counted. The increase in stock size was highest in the northern areas and the predation pressure of grey seals on clupeoids...... has increased accordingly. The diet of grey seal in the Baltic consists of ca. 20 fish species. The most abundant prey items in the Baltic proper are Baltic herring, sprat, and cod, and in the Bothnian Sea and Bothnian Bay Baltic herring, Coregonus sp., Baltic salmon, and sea trout. An adult seal...... consumes on average round 4.5 kg fish per day, of which 55% are clupeoids in the Baltic Main basin and 70% in the Bothnian Sea and Bothnian Bay. According to acoustic estimates, predator– prey distribution patterns, migration patterns, and multispecies analysis (SMS), the predation effect of grey seals...

  18. Prediction of pipeline corrosion rate based on grey Markov models

    International Nuclear Information System (INIS)

    Chen Yonghong; Zhang Dafa; Peng Guichu; Wang Yuemin

    2009-01-01

    Based on the model that combined by grey model and Markov model, the prediction of corrosion rate of nuclear power pipeline was studied. Works were done to improve the grey model, and the optimization unbiased grey model was obtained. This new model was used to predict the tendency of corrosion rate, and the Markov model was used to predict the residual errors. In order to improve the prediction precision, rolling operation method was used in these prediction processes. The results indicate that the improvement to the grey model is effective and the prediction precision of the new model combined by the optimization unbiased grey model and Markov model is better, and the use of rolling operation method may improve the prediction precision further. (authors)

  19. The race against the "septic shark".

    Science.gov (United States)

    Westphal, Martin; Kampmeier, Tim

    2015-01-01

    Great white sharks are responsible for about 10 cases of death annually worldwide, as compared with millions of deaths caused by sepsis. However, the basic principles of avoiding shark attacks and fighting sepsis seem to be similar: avoidance, attention, and speed, if necessary. The present review discusses the current status of the systemic inflammatory response syndrome (SIRS) criteria, which are actually content for discussion because of their low specificity. Current data suggest that one in eight patients with severe sepsis does not fulfill the SIRS criteria and is consequently missed, and therefore the calls for new definitions of sepsis are getting louder. Furthermore, the need for early treatment of sepsis and fast admission to an intensive care unit (ICU) with experienced stuff is reviewed as well as the early and appropriate initiation of therapy, namely antibiotic and volume therapy. A key feature is the analysis of the studies from the so-called "Sepsis Trilogy" (ProCESS, ARISE, and ProMiSe studies), with a focus on the status of early goal-directed therapy (EGDT). The authors of the "Sepsis Trilogy" concluded that there is no benefit regarding survival in septic patients by using EGDT as compared with standard therapy. However, the low mortality of the control groups within the "Sepsis Trilogy" studies as compared with the Rivers et al. study from 2001 leads to the conclusion that there has been an improvement in the therapy of septic patients, most probably due to the early initiation of therapy as a kind of "standard" in sepsis therapy. Finally, the phenomenon of a "large trial disease" is discussed, exemplary in a trial which investigated the maintenance of the "right" mean arterial pressure in sepsis patients. Even if the result of a large randomized trial might be that there is no difference between two study groups, the real exercise is to identify the patient collectives who might benefit or experience harm due to an intervention. In summary, as

  20. Identification and evaluation of shark bycatch in Georgia's commercial shrimp trawl fishery with implications for management

    Science.gov (United States)

    Belcher, C.N.; Jennings, C.A.

    2011-01-01

    Many US states have recreational and commercial fisheries that occur in nursery areas occupied by subadult sharks and can potentially affect their survival. Georgia is one of few US states without a directed commercial shark fishery, but the state has a large, nearshore penaeid shrimp trawl fishery in which small sharks occur as bycatch. During our 1995–1998 investigation of bycatch in fishery-dependent sampling events, 34% of 127 trawls contained sharks. This bycatch totalled 217 individuals from six species, with Atlantic sharpnose shark, Rhizoprionodon terraenovae (Richardson), the most common and finetooth shark, Carcharhinus isodon (Müller & Henle) and spinner shark, Carcharhinus brevipinna (Müller & Henle), the least common. The highest catch rates for sharks occurred during June and July and coincided with the peak months of the pupping season for many species. Trawl tow speed and tow time did not significantly influence catch rates for shark species. Gear configurations [net type, turtle excluder device (TED), bycatch reduction device] affected catch rates for shark species. Results of this study indicate gear restrictions, a delayed season opening, or reduced bar spacing on TEDs may reduce shark bycatch in this fishery.

  1. High Post-Capture Survival for Sharks, Rays and Chimaeras Discarded in the Main Shark Fishery of Australia?

    Science.gov (United States)

    Braccini, Matias; Van Rijn, Jay; Frick, Lorenz

    2012-01-01

    Most sharks, rays and chimaeras (chondrichthyans) taken in commercial fisheries are discarded (i.e. returned to the ocean either dead or alive). Quantifying the post-capture survival (PCS) of discarded species is therefore essential for the improved management and conservation of this group. For all chondrichthyans taken in the main shark fishery of Australia, we quantified the immediate PCS of individuals reaching the deck of commercial shark gillnet fishing vessels and applied a risk-based method to semi-quantitatively determine delayed and total PCS. Estimates of immediate, delayed and total PCS were consistent, being very high for the most commonly discarded species (Port Jackson shark, Australian swellshark, and spikey dogfish) and low for the most important commercial species (gummy and school sharks). Increasing gillnet soak time or water temperature significantly decreased PCS. Chondrichthyans with bottom-dwelling habits had the highest PCS whereas those with pelagic habits had the lowest PCS. The risk-based approach can be easily implemented as a standard practice of on-board observing programs, providing a convenient first-step assessment of the PCS of all species taken in commercial fisheries. PMID:22384270

  2. High post-capture survival for sharks, rays and chimaeras discarded in the main shark fishery of Australia?

    Science.gov (United States)

    Braccini, Matias; Van Rijn, Jay; Frick, Lorenz

    2012-01-01

    Most sharks, rays and chimaeras (chondrichthyans) taken in commercial fisheries are discarded (i.e. returned to the ocean either dead or alive). Quantifying the post-capture survival (PCS) of discarded species is therefore essential for the improved management and conservation of this group. For all chondrichthyans taken in the main shark fishery of Australia, we quantified the immediate PCS of individuals reaching the deck of commercial shark gillnet fishing vessels and applied a risk-based method to semi-quantitatively determine delayed and total PCS. Estimates of immediate, delayed and total PCS were consistent, being very high for the most commonly discarded species (Port Jackson shark, Australian swellshark, and spikey dogfish) and low for the most important commercial species (gummy and school sharks). Increasing gillnet soak time or water temperature significantly decreased PCS. Chondrichthyans with bottom-dwelling habits had the highest PCS whereas those with pelagic habits had the lowest PCS. The risk-based approach can be easily implemented as a standard practice of on-board observing programs, providing a convenient first-step assessment of the PCS of all species taken in commercial fisheries.

  3. Limbic grey matter changes in early Parkinson's disease.

    Science.gov (United States)

    Li, Xingfeng; Xing, Yue; Schwarz, Stefan T; Auer, Dorothee P

    2017-05-02

    The purpose of this study was to investigate local and network-related changes of limbic grey matter in early Parkinson's disease (PD) and their inter-relation with non-motor symptom severity. We applied voxel-based morphometric methods in 538 T1 MRI images retrieved from the Parkinson's Progression Markers Initiative website. Grey matter densities and cross-sectional estimates of age-related grey matter change were compared between subjects with early PD (n = 366) and age-matched healthy controls (n = 172) within a regression model, and associations of grey matter density with symptoms were investigated. Structural brain networks were obtained using covariance analysis seeded in regions showing grey matter abnormalities in PD subject group. Patients displayed focally reduced grey matter density in the right amygdala, which was present from the earliest stages of the disease without further advance in mild-moderate disease stages. Right amygdala grey matter density showed negative correlation with autonomic dysfunction and positive with cognitive performance in patients, but no significant interrelations were found with anxiety scores. Patients with PD also demonstrated right amygdala structural disconnection with less structural connectivity of the right amygdala with the cerebellum and thalamus but increased covariance with bilateral temporal cortices compared with controls. Age-related grey matter change was also increased in PD preferentially in the limbic system. In conclusion, detailed brain morphometry in a large group of early PD highlights predominant limbic grey matter deficits with stronger age associations compared with controls and associated altered structural connectivity pattern. This provides in vivo evidence for early limbic grey matter pathology and structural network changes that may reflect extranigral disease spread in PD. Hum Brain Mapp, 2017. © 2017 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. © 2017 The

  4. Grey literature: An important resource in systematic reviews.

    Science.gov (United States)

    Paez, Arsenio

    2017-12-21

    Systematic reviews aid the analysis and dissemination of evidence, using rigorous and transparent methods to generate empirically attained answers to focused research questions. Identifying all evidence relevant to the research questions is an essential component, and challenge, of systematic reviews. Grey literature, or evidence not published in commercial publications, can make important contributions to a systematic review. Grey literature can include academic papers, including theses and dissertations, research and committee reports, government reports, conference papers, and ongoing research, among others. It may provide data not found within commercially published literature, providing an important forum for disseminating studies with null or negative results that might not otherwise be disseminated. Grey literature may thusly reduce publication bias, increase reviews' comprehensiveness and timeliness and foster a balanced picture of available evidence. Grey literature's diverse formats and audiences can present a significant challenge in a systematic search for evidence. However, the benefits of including grey literature may far outweigh the cost in time and resource needed to search for it, and it is important for it to be included in a systematic review or review of evidence. A carefully thought out grey literature search strategy may be an invaluable component of a systematic review. This narrative review provides guidance about the benefits of including grey literature in a systematic review, and sources for searching through grey literature. An illustrative example of a search for evidence within grey literature sources is presented to highlight the potential contributions of such a search to a systematic review. Benefits and challenges of grey literature search methods are discussed, and recommendations made. © 2017 Chinese Cochrane Center, West China Hospital of Sichuan University and John Wiley & Sons Australia, Ltd.

  5. Unusual MRI findings in grey matter heteropia

    International Nuclear Information System (INIS)

    Soto Ares, G.; Hamon-Kerautret, M.; Leclerc, X.; Pruvo, J.P.; Houlette, C.; Godefroy, O.

    1998-01-01

    We report unusual MRI patterns in patients with grey matter heterotopia. Standard T1- and T2-weighted spin-echo and inversion-recovery sequences were used in 22 patients presenting with seizures or developmental delay. The images were reviewed for signal change surrounding white matter and for atypical size, morphology or topography. We found 10 cases of subependymal heterotopias 11 of focal subcortical heterotopia and of diffuse subcortical heterotopia. On clinical or MRI grounds, 8 cases were considered unusual: 2 of the subependymal type, 2 of focal subcortical heterotopia with white matter abnormalities, 2 of focal subcortical heterotopia with no clinicoradiological correlation 1 of extensive hemispheric subcortical heterotopia and 1 of diffuse subcortical heterotopia confined to the frontal lobe. The classical classification of heterotopia enables easy radiological diagnosis even in cases with unusual patterns. In some cases, heterogeneity and high signal in surrounding white matter can be found. Cortical dysplasia is the most frequent associated malformation. (orig.)

  6. Repozitář a webový portál GreyGuide:Odpověď GreyNet na Deklaraci z Pisy

    OpenAIRE

    Farace, Dominic

    2014-01-01

    In December 2013, the GreyGuide was launched and in early 2014 GreyNet welcomed far reaching developments in its resource management. These developments are in line with the “Pisa Declaration on Policy Development for Grey Literature Resources (May 16, 2014)”. In compliance with this 15-point roadmap, a selection of GreyNet’s web-based content will now migrate to the GreyGuide allowing for seamless browse, search, and retrieval across its collections.

  7. The Influence of Culture on the International Management of Shark Finning

    Science.gov (United States)

    Dell'Apa, Andrea; Chad Smith, M.; Kaneshiro-Pineiro, Mahealani Y.

    2014-08-01

    Shark finning is prohibited in many countries, but high prices for fins from the Asian market help maintain the international black-market and poaching. Traditional shark fin bans fail to recognize that the main driver of fin exploitation is linked to cultural beliefs about sharks in traditional Chinese culture. Therefore, shark finning should be addressed considering the social science approach as part of the fishery management scheme. This paper investigates the cultural significance of sharks in traditional Chinese and Hawaiian cultures, as valuable examples of how specific differences in cultural beliefs can drive individuals' attitudes toward the property of shark finning. We suggest the use of a social science approach that can be useful in the design of successful education campaigns to help change individuals' attitudes toward shark fin consumption. Finally, alternative management strategies for commercial fishers are provided to maintain self-sustainability of local coastal communities.

  8. The use of positive reinforcement in training zebra sharks (Stegostoma fasciatum).

    Science.gov (United States)

    Marranzino, Ashley

    2013-01-01

    Positive reinforcement training (PRT) was used on 4 adult zebra sharks, Stegostoma fasciatum, housed at the Downtown Aquarium, Denver, to determine the ability of zebra sharks to become desensitized to various stimuli associated with veterinary procedures. One male and 3 female sharks were trained for 12 weeks. As a result of PRT, all 4 zebra sharks were desensitized to staying within a closed holding tank off of the main exhibit, the presence of multiple trainers in the closed holding tank, and tactile stimulation. One of the 4 zebra sharks was also successfully desensitized to the presence of a stretcher being brought into the holding tank. All of these procedures are common in veterinary examinations, and it is hoped that desensitization to these stimuli will reduce the stress associated with examinations. The training accomplished has allowed for easier maintenance of the zebra sharks by the aquarium staff and an improvement in the care of the sharks.

  9. Digestive enzyme activities are higher in the shortfin mako shark, Isurus oxyrinchus, than in ectothermic sharks as a result of visceral endothermy.

    Science.gov (United States)

    Newton, Kyle C; Wraith, James; Dickson, Kathryn A

    2015-08-01

    Lamnid sharks are regionally endothermic fishes that maintain visceral temperatures elevated above the ambient water temperature. Visceral endothermy is thought to increase rates of digestion and food processing and allow thermal niche expansion. We tested the hypothesis that, at in vivo temperatures, the endothermic shortfin mako shark, Isurus oxyrinchus, has higher specific activities of three digestive enzymes-gastric pepsin and pancreatic trypsin and lipase-than the thresher shark, Alopias vulpinus, and the blue shark, Prionace glauca, neither of which can maintain elevated visceral temperatures. Homogenized stomach or pancreas tissue obtained from sharks collected by pelagic longline was incubated at both 15 and 25 °C, at saturating substrate concentrations, to quantify tissue enzymatic activity. The mako had significantly higher enzyme activities at 25 °C than did the thresher and blue sharks at 15 °C. This difference was not a simple temperature effect, because at 25 °C the mako had higher trypsin activity than the blue shark and higher activities for all enzymes than the thresher shark. We also hypothesized that the thermal coefficient, or Q 10 value, would be higher for the mako shark than for the thresher and blue sharks because of its more stable visceral temperature. However, the mako and thresher sharks had similar Q 10 values for all enzymes, perhaps because of their closer phylogenetic relationship. The higher in vivo digestive enzyme activities in the mako shark should result in higher rates of food processing and may represent a selective advantage of regional visceral endothermy.

  10. A new metric for measuring condition in large predatory sharks.

    Science.gov (United States)

    Irschick, D J; Hammerschlag, N

    2014-09-01

    A simple metric (span condition analysis; SCA) is presented for quantifying the condition of sharks based on four measurements of body girth relative to body length. Data on 104 live sharks from four species that vary in body form, behaviour and habitat use (Carcharhinus leucas, Carcharhinus limbatus, Ginglymostoma cirratum and Galeocerdo cuvier) are given. Condition shows similar levels of variability among individuals within each species. Carcharhinus leucas showed a positive relationship between condition and body size, whereas the other three species showed no relationship. There was little evidence for strong differences in condition between males and females, although more male sharks are needed for some species (e.g. G. cuvier) to verify this finding. SCA is potentially viable for other large marine or terrestrial animals that are captured live and then released. © 2014 The Fisheries Society of the British Isles.

  11. Switch from sexual to parthenogenetic reproduction in a zebra shark.

    Science.gov (United States)

    Dudgeon, Christine L; Coulton, Laura; Bone, Ren; Ovenden, Jennifer R; Thomas, Severine

    2017-01-16

    Parthenogenesis is a natural form of asexual reproduction in which embryos develop in the absence of fertilisation. Most commonly found in plants and invertebrate organisms, an increasing number of vertebrate species have recently been reported employing this reproductive strategy. Here we use DNA genotyping to report the first demonstration of an intra-individual switch from sexual to parthenogenetic reproduction in a shark species, the zebra shark Stegostoma fasciatum. A co-housed, sexually produced daughter zebra shark also commenced parthenogenetic reproduction at the onset of maturity without any prior mating. The demonstration of parthenogenesis in these two conspecific individuals with different sexual histories provides further support that elasmobranch fishes may flexibly adapt their reproductive strategy to environmental circumstances.

  12. Maternal transfer of organohalogenated compounds in sharks and stingrays.

    Science.gov (United States)

    Weijs, Liesbeth; Briels, Nathalie; Adams, Douglas H; Lepoint, Gilles; Das, Krishna; Blust, Ronny; Covaci, Adrian

    2015-03-15

    Elasmobranchs can bioaccumulate considerable amounts of persistent organic pollutants (POPs) and utilize several reproductive strategies thereby influencing maternal transfer of contaminants. This study provides preliminary data on the POP transfer from pregnant females to offspring of three species (Atlantic stingrays, bonnethead, blacktip sharks) with different reproduction modes (aplacental, placental viviparity). Polychlorinated biphenyl (PCB) levels were generally higher than any other POPs. Stingrays and blacktip shark embryos contained the lowest POP concentrations while bonnetheads and the blacktip adult female had the highest concentrations. Results suggest that POPs are more readily transferred from the mother to the embryo compared to what is transferred to ova in stingrays. Statistically significant differences in levels of selected POPs were found between embryos from the left and right uterus within the same litter as well as between female and male embryos within the same litter for bonnetheads, but not for the blacktip sharks. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Phylogeographic history of grey wolves in Europe

    Directory of Open Access Journals (Sweden)

    Dykyy Ihor

    2010-04-01

    Full Text Available Abstract Background While it is generally accepted that patterns of intra-specific genetic differentiation are substantially affected by glacial history, population genetic processes occurring during Pleistocene glaciations are still poorly understood. In this study, we address the question of the genetic consequences of Pleistocene glaciations for European grey wolves. Combining our data with data from published studies, we analysed phylogenetic relationships and geographic distribution of mitochondrial DNA haplotypes for 947 contemporary European wolves. We also compared the contemporary wolf sequences with published sequences of 24 ancient European wolves. Results We found that haplotypes representing two haplogroups, 1 and 2, overlap geographically, but substantially differ in frequency between populations from south-western and eastern Europe. A comparison between haplotypes from Europe and other continents showed that both haplogroups are spread throughout Eurasia, while only haplogroup 1 occurs in contemporary North American wolves. All ancient wolf samples from western Europe that dated from between 44,000 and 1,200 years B.P. belonged to haplogroup 2, suggesting the long-term predominance of this haplogroup in this region. Moreover, a comparison of current and past frequencies and distributions of the two haplogroups in Europe suggested that haplogroup 2 became outnumbered by haplogroup 1 during the last several thousand years. Conclusions Parallel haplogroup replacement, with haplogroup 2 being totally replaced by haplogroup 1, has been reported for North American grey wolves. Taking into account the similarity of diets reported for the late Pleistocene wolves from Europe and North America, the correspondence between these haplogroup frequency changes may suggest that they were associated with ecological changes occurring after the Last Glacial Maximum.

  14. Grey relevant analysis of sodium critical heat flux in annular channel and the establishing of grey model

    International Nuclear Information System (INIS)

    Zhou Tao; Su Guanghui; Liao Yixiang; Zhang Weizhong; Qiu Suizheng; Jia Dounan

    1999-12-01

    Using grey systems theory and experimental data obtained from sodium boiling test loop in China, grey mutual analysis is done to some parameters influencing sodium CHF. The results of CHF are predicted by using GM (1,1) model. The GM(1,h) model is made up for creating CHF model. The results are in good agreement with the experimental data

  15. Application of Shark Skin Flow Control Techniques to Airflow

    Science.gov (United States)

    Morris, Jackson Alexander

    Due to millions of years of evolution, sharks have evolved to become quick and efficient ocean apex predators. Shark skin is made up of millions of microscopic scales, or denticles, that are approximately 0.2 mm in size. Scales located on the shark's body where separation control is paramount (such as behind the gills or the trailing edge of the pectoral fin) are capable of bristling. These scales are hypothesized to act as a flow control mechanism capable of being passively actuated by reversed flow. It is believed that shark scales are strategically sized to interact with the lower 5% of a boundary layer, where reversed flow occurs at the onset of boundary layer separation. Previous research has shown shark skin to be capable of controlling separation in water. This thesis aims to investigate the same passive flow control techniques in air. To investigate this phenomenon, several sets of microflaps were designed and manufactured with a 3D printer. The microflaps were designed in both 2D (rectangular) and 3D (mirroring shark scale geometry) variants. These microflaps were placed in a low-speed wind tunnel in the lower 5% of the boundary layer. Solid fences and a flat plate diffuser with suction were placed in the tunnel to create different separated flow regions. A hot film probe was used to measure velocity magnitude in the streamwise plane of the separated regions. The results showed that low-speed airflow is capable of bristling objects in the boundary layer. When placed in a region of reverse flow, the microflaps were passively actuated. Microflaps fluctuated between bristled and flat states in reverse flow regions located close to the reattachment zone.

  16. DNA capture reveals transoceanic gene flow in endangered river sharks.

    Science.gov (United States)

    Li, Chenhong; Corrigan, Shannon; Yang, Lei; Straube, Nicolas; Harris, Mark; Hofreiter, Michael; White, William T; Naylor, Gavin J P

    2015-10-27

    For over a hundred years, the "river sharks" of the genus Glyphis were only known from the type specimens of species that had been collected in the 19th century. They were widely considered extinct until populations of Glyphis-like sharks were rediscovered in remote regions of Borneo and Northern Australia at the end of the 20th century. However, the genetic affinities between the newly discovered Glyphis-like populations and the poorly preserved, original museum-type specimens have never been established. Here, we present the first (to our knowledge) fully resolved, complete phylogeny of Glyphis that includes both archival-type specimens and modern material. We used a sensitive DNA hybridization capture method to obtain complete mitochondrial genomes from all of our samples and show that three of the five described river shark species are probably conspecific and widely distributed in Southeast Asia. Furthermore we show that there has been recent gene flow between locations that are separated by large oceanic expanses. Our data strongly suggest marine dispersal in these species, overturning the widely held notion that river sharks are restricted to freshwater. It seems that species in the genus Glyphis are euryhaline with an ecology similar to the bull shark, in which adult individuals live in the ocean while the young grow up in river habitats with reduced predation pressure. Finally, we discovered a previously unidentified species within the genus Glyphis that is deeply divergent from all other lineages, underscoring the current lack of knowledge about the biodiversity and ecology of these mysterious sharks.

  17. Feeding of the megamouth shark (Pisces: Lamniformes: Megachasmidae) predicted by its hyoid arch: a biomechanical approach.

    Science.gov (United States)

    Tomita, Taketeru; Sato, Keiichi; Suda, Kenta; Kawauchi, Junro; Nakaya, Kazuhiro

    2011-05-01

    Studies of the megamouth shark, one of three planktivorous sharks, can provide information about their evolutionary history. Megamouth shark feeding has never been observed in life animals, but two alternative hypotheses on biomechanics suggest either feeding, i.e., ram feeding or suction feeding. In this study, the second moment of area of the ceratohyal cartilages, which is an indicator of the flexural stiffness of the cartilages, is calculated for 21 species of ram- and suction-feeding sharks using computed tomography. The results indicate that suction-feeding sharks have ceratohyal cartilages with a larger second moment of area than ram-feeding sharks. The result also indicates that the ram-suction index, which is an indicator of relative contribution of ram and suction behavior, is also correlated with the second moment of area of the ceratohyal. Considering that large bending stresses are expected to be applied to the ceratohyal cartilage during suction, the larger second moment of area of the ceratohyal of suction-feeding sharks can be interpreted as an adaptation for suction feeding. Based on the small second moment of area of the ceratohyal cartilage of the megamouth shark, the feeding mode of the megamouth shark is considered to be ram feeding, similar to the planktivorous basking shark. From these results, an evolutionary scenario of feeding mechanics of three species of planktivorous sharks can be suggested. In this scenario, the planktivorous whale shark evolved ram feeding from a benthic suction-feeding ancestor. Ram feeding in the planktivorous megamouth shark and the basking shark evolved from ram feeding swimming-type ancestors and that both developed their unique filtering system to capture small-sized prey. Copyright © 2011 Wiley-Liss, Inc.

  18. Quantification of Massive Seasonal Aggregations of Blacktip Sharks (Carcharhinus limbatus) in Southeast Florida.

    Science.gov (United States)

    Kajiura, Stephen M; Tellman, Shari L

    2016-01-01

    Southeast Florida witnesses an enormous seasonal influx of upper trophic level marine predators each year as massive aggregations of migrating blacktip sharks (Carcharhinus limbatus) overwinter in nearshore waters. The narrow shelf and close proximity of the Gulf Stream current to the Palm Beach County shoreline drive tens of thousands of sharks to the shallow, coastal environment. This natural bottleneck provides a unique opportunity to estimate relative abundance. Over a four year period from 2011-2014, an aerial survey was flown approximately biweekly along the length of Palm Beach County. A high definition video camera and digital still camera mounted out of the airplane window provided a continuous record of the belt transect which extended 200 m seaward from the shoreline between Boca Raton Inlet and Jupiter Inlet. The number of sharks within the survey transect was directly counted from the video. Shark abundance peaked in the winter (January-March) with a maximum in 2011 of 12,128 individuals counted within the 75.6 km(-2) belt transect. This resulted in a maximum density of 803.2 sharks km(-2). By the late spring (April-May), shark abundance had sharply declined to 1.1% of its peak, where it remained until spiking again in January of the following year. Shark abundance was inversely correlated with water temperature and large numbers of sharks were found only when water temperatures were less than 25 °C. Shark abundance was also correlated with day of the year but not with barometric pressure. Although shark abundance was not correlated with photoperiod, the departure of the sharks from southeast Florida occurred around the vernal equinox. The shark migration along the United States eastern seaboard corresponds spatially and temporally with the spawning aggregations of various baitfish species. These baseline abundance data can be compared to future studies to determine if shark population size is changing and if sharks are restricting their southward

  19. SHARK-NIR system design analysis overview

    Science.gov (United States)

    Viotto, Valentina; Farinato, Jacopo; Greggio, Davide; Vassallo, Daniele; Carolo, Elena; Baruffolo, Andrea; Bergomi, Maria; Carlotti, Alexis; De Pascale, Marco; D'Orazi, Valentina; Fantinel, Daniela; Magrin, Demetrio; Marafatto, Luca; Mohr, Lars; Ragazzoni, Roberto; Salasnich, Bernardo; Verinaud, Christophe

    2016-08-01

    In this paper, we present an overview of the System Design Analysis carried on for SHARK-NIR, the coronagraphic camera designed to take advantage of the outstanding performance that can be obtained with the FLAO facility at the LBT, in the near infrared regime. Born as a fast-track project, the system now foresees both coronagraphic direct imaging and spectroscopic observing mode, together with a first order wavefront correction tool. The analysis we here report includes several trade-offs for the selection of the baseline design, in terms of optical and mechanical engineering, and the choice of the coronagraphic techniques to be implemented, to satisfy both the main scientific drivers and the technical requirements set at the level of the telescope. Further care has been taken on the possible exploitation of the synergy with other LBT instrumentation, like LBTI. A set of system specifications is then flown down from the upper level requirements to finally ensure the fulfillment of the science drivers. The preliminary performance budgets are presented, both in terms of the main optical planes stability and of the image quality, including the contributions of the main error sources in different observing modes.

  20. Shark-bitten vertebrate coprolites from the Miocene of Maryland

    Science.gov (United States)

    Godfrey, Stephen J.; Smith, Joshua B.

    2010-05-01

    Coprolites (fossilized feces) preserve a wide range of biogenic components, from bacteria and spores to a variety of vertebrate tissues. Two coprolites from the Calvert Cliffs outcrop belt (Miocene-aged Chesapeake Group), MD, USA, preserve shark tooth impressions in the form of partial dental arcades. The specimens are the first known coprolites to preserve vertebrate tooth marks. They provide another example of trace fossils providing evidence of prehistoric animal behaviors that cannot be directly approached through the study of body fossils. Shark behaviors that could account for these impressions include: (1) aborted coprophagy, (2) benthic or nektonic exploration, or (3) predation.

  1. Grey water treatment in UASB reactor at ambient temperature.

    Science.gov (United States)

    Elmitwalli, T A; Shalabi, M; Wendland, C; Otterpohl, R

    2007-01-01

    In this paper, the feasibility of grey water treatment in a UASB reactor was investigated. The batch recirculation experiments showed that a maximum total-COD removal of 79% can be obtained in grey-water treatment in the UASB reactor. The continuous operational results of a UASB reactor treating grey water at different hydraulic retention time (HRT) of 20, 12 and 8 hours at ambient temperature (14-24 degrees C) showed that 31-41% of total COD was removed. These results were significantly higher than that achieved by a septic tank (11-14%), the most common system for grey water pre-treatment, at HRT of 2-3 days. The relatively lower removal of total COD in the UASB reactor was mainly due to a higher amount of colloidal COD in the grey water, as compared to that reported in domestic wastewater. The grey water had a limited amount of nitrogen, which was mainly in particulate form (80-90%). The UASB reactor removed 24-36% and 10-24% of total nitrogen and total phosphorus, respectively, in the grey water, due to particulate nutrients removal by physical entrapment and sedimentation. The sludge characteristics of the UASB reactor showed that the system had stable performance and the recommended HRT for the reactor is 12 hours.

  2. Using atmospheric pressure plasma treatment for treating grey cotton fabric.

    Science.gov (United States)

    Kan, Chi-Wai; Lam, Chui-Fung; Chan, Chee-Kooi; Ng, Sun-Pui

    2014-02-15

    Conventional wet treatment, desizing, scouring and bleaching, for grey cotton fabric involves the use of high water, chemical and energy consumption which may not be considered as a clean process. This study aims to investigate the efficiency of the atmospheric pressure plasma (APP) treatment on treating grey cotton fabric when compared with the conventional wet treatment. Grey cotton fabrics were treated with different combinations of plasma parameters with helium and oxygen gases and also through conventional desizing, scouring and bleaching processes in order to obtain comparable results. The results obtained from wicking and water drop tests showed that wettability of grey cotton fabrics was greatly improved after plasma treatment and yielded better results than conventional desizing and scouring. The weight reduction of plasma treated grey cotton fabrics revealed that plasma treatment can help remove sizing materials and impurities. Chemical and morphological changes in plasma treated samples were analysed by FTIR and SEM, respectively. Finally, dyeability of the plasma treated and conventional wet treated grey cotton fabrics was compared and the results showed that similar dyeing results were obtained. This can prove that plasma treatment would be another choice for treating grey cotton fabrics. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Contrast between white and grey matter: MRI appearance with ageing

    International Nuclear Information System (INIS)

    Magnaldi, S.; Ukmar, M.; Vasciaveo, A.; Longo, R.; Pozzi-Mucelli, R.S.

    1993-01-01

    MRI contrast between white and grey matter appears to be higher in young normal subjects than in older patients. The aim of the present study was to investigate the possible relationships between these changes in contrast and ageing. It consisted of two parts. In the first part we retrospectively evaluated 140 MRI brain examinations of healthy subjects, 20 per decade (age range 20-90 years), in whom the contrast was subjectively scored. In the second part we prospectively measured the actual T1, spin density (SD) and T2 values of white and grey matter in another 22 healthy subjects (age range 20-80 years). In the first group of subjects a progressive decrease in white/grey matter contrast was observed with ageing. In the second group of subjects the T1, SD and T2 values of white matter were always shorter than those of grey matter. There is a close relation among T1, SD and T2 values of white and grey matter with ageing. We suggest that there is a progressive loss of white/grey matter contrast with ageing. Such a phenomenon is possibly due to an increased water content in the white matter and the progressive neuronal loss in the grey matter that occurs with age. (orig.)

  4. Bibliometric study of grey literature in core veterinary medical journals.

    Science.gov (United States)

    Pelzer, Nancy L; Wiese, William H

    2003-10-01

    Grey literature has been perceived by many as belonging to the primary sources of information and has become an accepted method of nonconventional communication in the sciences and medicine. Since little is known about the use and nature of grey literature in veterinary medicine, a systematic study was done to analyze and characterize the bibliographic citations appearing in twelve core veterinary journals. Citations from 2,159 articles published in twelve core veterinary journals in 2000 were analyzed to determine the portion of citations from grey literature. Those citations were further analyzed and categorized according to the type of publication. Citation analysis yielded 55,823 citations, of which 3,564 (6.38%) were considered to be grey literature. Four veterinary specialties, internal medicine, pathology, theriogenology, and microbiology, accounted for 70% of the total number of articles. Three small-animal clinical practice journals cited about 2.5-3% grey literature, less than half that of journals with basic research orientations, where results ranged from almost 6% to approximately 10% grey literature. Nearly 90% of the grey literature appeared as conferences, government publications, and corporate organization literature. The results corroborate other reported research that the incidence of grey literature is lower in medicine and biology than in some other fields, such as aeronautics and agriculture. As in other fields, use of the Internet and the Web has greatly expanded the communication process among veterinary professionals. The appearance of closed community email forums and specialized discussion groups within the veterinary profession is an example of what could become a new kind of grey literature.

  5. Comparative genomic analysis of the MHC: the evolution of class I duplication blocks, diversity and complexity from shark to man.

    Science.gov (United States)

    Kulski, Jerzy K; Shiina, Takashi; Anzai, Tatsuya; Kohara, Sakae; Inoko, Hidetoshi

    2002-12-01

    The major histocompatibility complex (MHC) genomic region is composed of a group of linked genes involved functionally with the adaptive and innate immune systems. The class I and class II genes are intrinsic features of the MHC and have been found in all the jawed vertebrates studied so far. The MHC genomic regions of the human and the chicken (B locus) have been fully sequenced and mapped, and the mouse MHC sequence is almost finished. Information on the MHC genomic structures (size, complexity, genic and intergenic composition and organization, gene order and number) of other vertebrates is largely limited or nonexistent. Therefore, we are mapping, sequencing and analyzing the MHC genomic regions of different human haplotypes and at least eight nonhuman species. Here, we review our progress with these sequences and compare the human MHC structure with that of the nonhuman primates (chimpanzee and rhesus macaque), other mammals (pigs, mice and rats) and nonmammalian vertebrates such as birds (chicken and quail), bony fish (medaka, pufferfish and zebrafish) and cartilaginous fish (nurse shark). This comparison reveals a complex MHC structure for mammals and a relatively simpler design for nonmammalian animals with a hypothetical prototypic structure for the shark. In the mammalian MHC, there are two to five different class I duplication blocks embedded within a framework of conserved nonclass I and/or nonclass II genes. With a few exceptions, the class I framework genes are absent from the MHC of birds, bony fish and sharks. Comparative genomics of the MHC reveal a highly plastic region with major structural differences between the mammalian and nonmammalian vertebrates. Additional genomic data are needed on animals of the reptilia, crocodilia and marsupial classes to find the origins of the class I framework genes and examples of structures that may be intermediate between the simple and complex MHC organizations of birds and mammals, respectively.

  6. Modification of grey scale in computer tomographic images

    International Nuclear Information System (INIS)

    Hemmingsson, A.; Jung, B.

    1980-01-01

    Optimum perception of minute but relevant attenuation differences in CT images often requires display window settings so narrow that a considerable fraction of the image appears completely black or white and consequently without structure. In order to improve the display characteristics two principles of grey scale modification are presented. In one method the pixel contents are displayed unchanged within a selectable attenuation band but moved towards the limits of the band for pixels that are outside it. In the other the grey scale is arranged to a constant number of pixels per grey scale interval. (Auth.)

  7. The Species and Origin of Shark Fins in Taiwan's Fishing Ports, Markets, and Customs Detention: A DNA Barcoding Analysis.

    Science.gov (United States)

    Chuang, Po-Shun; Hung, Tzu-Chiao; Chang, Hung-An; Huang, Chien-Kang; Shiao, Jen-Chieh

    2016-01-01

    The increasing consumption of shark products, along with the shark's fishing vulnerabilities, has led to the decrease in certain shark populations. In this study we used a DNA barcoding method to identify the species of shark landings at fishing ports, shark fin products in retail stores, and shark fins detained by Taiwan customs. In total we identified 23, 24, and 14 species from 231 fishing landings, 316 fin products, and 113 detained shark fins, respectively. All the three sample sources were dominated by Prionace glauca, which accounted for more than 30% of the collected samples. Over 60% of the species identified in the fin products also appeared in the port landings, suggesting the domestic-dominance of shark fin products in Taiwan. However, international trade also contributes a certain proportion of the fin product markets, as four species identified from the shark fin products are not found in Taiwan's waters, and some domestic-available species were also found in the customs-detained sample. In addition to the species identification, we also found geographical differentiation in the cox1 gene of the common thresher sharks (Alopias vulpinus), the pelagic thresher shark (A. pelagicus), the smooth hammerhead shark (Sphyrna zygaena), and the scalloped hammerhead shark (S. lewini). This result might allow fishing authorities to more effectively trace the origins as well as enforce the management and conservation of these sharks.

  8. The Species and Origin of Shark Fins in Taiwan's Fishing Ports, Markets, and Customs Detention: A DNA Barcoding Analysis.

    Directory of Open Access Journals (Sweden)

    Po-Shun Chuang

    Full Text Available The increasing consumption of shark products, along with the shark's fishing vulnerabilities, has led to the decrease in certain shark populations. In this study we used a DNA barcoding method to identify the species of shark landings at fishing ports, shark fin products in retail stores, and shark fins detained by Taiwan customs. In total we identified 23, 24, and 14 species from 231 fishing landings, 316 fin products, and 113 detained shark fins, respectively. All the three sample sources were dominated by Prionace glauca, which accounted for more than 30% of the collected samples. Over 60% of the species identified in the fin products also appeared in the port landings, suggesting the domestic-dominance of shark fin products in Taiwan. However, international trade also contributes a certain proportion of the fin product markets, as four species identified from the shark fin products are not found in Taiwan's waters, and some domestic-available species were also found in the customs-detained sample. In addition to the species identification, we also found geographical differentiation in the cox1 gene of the common thresher sharks (Alopias vulpinus, the pelagic thresher shark (A. pelagicus, the smooth hammerhead shark (Sphyrna zygaena, and the scalloped hammerhead shark (S. lewini. This result might allow fishing authorities to more effectively trace the origins as well as enforce the management and conservation of these sharks.

  9. Shark teeth as edged weapons: serrated teeth of three species of selachians.

    Science.gov (United States)

    Moyer, Joshua K; Bemis, William E

    2017-02-01

    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 two basic types of serrations. A primary serration consists of three layers of enameloid with underlying dentine filling the serration's base. All three species studied have primary serrations, although the dentine component differs (orthodentine in Tiger and Blue Sharks; osteodentine in the White Shark). Smaller secondary serrations are found in the Tiger Shark, formed solely by enameloid with no contribution from underlying dentine. Secondary serrations are effectively "serrations within serrations" that allow teeth to cut at different scales. We propose that the cutting edges of Tiger Shark teeth, equipped with serrations at different scales, are linked to a diet that includes large, hard-shelled prey (e.g., sea turtles) as well as smaller, softer prey such as fishes. We discuss other aspects of serration form and function by making analogies to man-made cutting implements, such as knives and saws. Copyright © 2016 Elsevier GmbH. All rights reserved.

  10. Introduction to Northeast Pacific Shark Biology, Research, and Conservation, Part B.

    Science.gov (United States)

    Larson, Shawn E; Lowry, Dayv

    Sharks are iconic, sometimes apex, predators found in every ocean. Because of their ecological role as predators and concern over the stability of their populations, there has been an increasing amount of work focused on shark conservation around the world in recent decades. The populations of sharks that reside in the Northeast Pacific (NEP) Ocean bordering the west coast of the United States reside in one of the most economically and ecologically important oceanic regions in the world. Volume 78 of Advances in Marine Biology (AMB) is a companion to Volume 77, which focused primarily on NEP shark biodiversity, organismal biology, and ecology. Volume 78 highlights fisheries and the conservation implications of fisheries management; shark population modelling and the conservation impacts of these models given that many life history metrics of NEP sharks necessary to accurately run these models are still unknown; the value of captive sharks to the biology, outreach, and conservation of NEP sharks; and the conservation value of citizen science and shark ecotourism. Together these volumes encapsulate the current state of the knowledge for sharks in the NEP and lay the foundation for protecting, managing, and learning from these species in the face evolving natural conditions and societal opinions. © 2017 Elsevier Ltd All rights reserved.

  11. Utility of mesohabitat features for determining habitat associations of subadult sharks in Georgia’s estuaries

    Science.gov (United States)

    Belcher, C.N.; Jennings, Cecil A.

    2010-01-01

    We examined the affects of selected water quality variables on the presence of subadult sharks in six of nine Georgia estuaries. During 231 longline sets, we captured 415 individuals representing nine species. Atlantic sharpnose shark (Rhizoprionodon terranovae), bonnethead (Sphyrna tiburo), blacktip shark (Carcharhinus limbatus) and sandbar shark (C. plumbeus) comprised 96.1% of the catch. Canonical correlation analysis (CCA) was used to assess environmental influences on the assemblage of the four common species. Results of the CCA indicated Bonnethead Shark and Sandbar Shark were correlated with each other and with a subset of environmental variables. When the species occurred singly, depth was the defining environmental variable; whereas, when the two co-occurred, dissolved oxygen and salinity were the defining variables. Discriminant analyses (DA) were used to assess environmental influences on individual species. Results of the discriminant analyses supported the general CCA findings that the presence of bonnethead and sandbar shark were the only two species that correlated with environmental variables. In addition to depth and dissolved oxygen, turbidity influenced the presence of sandbar shark. The presence of bonnethead shark was influenced primarily by salinity and turbidity. Significant relationships existed for both the CCA and DA analyses; however, environmental variables accounted for shark species among sites.

  12. Biological data from sharks landed within the United Arab Emirates ...

    African Journals Online (AJOL)

    Landing site and market surveys of sharks landed along the Arabian Gulf coast of the United Arab Emirates were undertaken between October 2010 and September 2012 to obtain biological data from this artisanal fishery. Data were collected on the size and sex of 12 482 individuals representing 30 species. Maximum ...

  13. Ferromanganese oxides on sharks' teeth from Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.

    The mineralogy, composition and growth rates of ferromanganese (Fe-Mn) oxides over the sharks' teeth from the Central Indian Ocean Basin are presented. The trends of metal enrichment (Mn, Ni, Cu and Zn) and depletion (Fe and Co), the Mn/Fe ratio...

  14. Some observations on the reproductive biology of the sixgill shark ...

    African Journals Online (AJOL)

    Observations are made of the maturation status of 81 male and 88 female sixgill sharks Hexanchus griseus from southern African waters. Males mature at about 310 cm total length (TL) with the calcification of the terminal cartilage elements of the claspers. Determination of maturity for females was problematic, but most ...

  15. Beyond Jaws : rediscovering the 'lost sharks' of southern Africa ...

    African Journals Online (AJOL)

    Southern Africa has one of the richest and most diverse chondrichthyan faunas in the world, comprising all 13 orders, 49 families, 111 genera and approximately 204 species. This represents nearly 20% of all known chondrichthyans, and includes 117 shark, 79 batoid and 8 chimaera species. A greater diversity of ...

  16. Mortality estimates for juvenile dusky sharks carcharhinus Obscurus ...

    African Journals Online (AJOL)

    A maximum likelihood model is developed, using mark-recapture data, to estimate total and fishing mortality rates for the dusky shark Carcharhinus obscurus in South Africa. The model accounts for tag-shedding, nonreporting of recaptured tags, the multiple release and single recapture nature of the study and the usage of ...

  17. Age, growth and reproductive biology of the blue shark Prionace ...

    African Journals Online (AJOL)

    The age, growth and reproductive biology of the blue shark Prionace glauca from South African waters were assessed using 205 specimens, ranging in total length (TL) from 72 to 313 cm. Greater number of males (120) than females (85) were examined as they were more frequently caught. Age and growth parameters ...

  18. Workshop on SHAring and Reusing architectural Knowledge: (SHARK 2011)

    NARCIS (Netherlands)

    Avgeriou, P.; Lago, P.; Kruchten, P.; Taylor, R.N.; Gall, H.; Medvidovic, N.

    2011-01-01

    Architectural Knowledge (AK) is defined as the integrated representation of the software architecture of a software-intensive system or family of systems along with architectural decisions and their rationale, external influence and the development environment. The SHARK workshop series focuses on

  19. Role of polyols in thermal inactivation of shark ornithine transcarbamoylase

    Czech Academy of Sciences Publication Activity Database

    Bellocco, E.; Lagana, G.; Barreca, D.; Ficarra, S.; Tellone, E.; Magazu, S.; Branca, C.; Kotyk, Arnošt; Galtieri, A.; Leuzzi, U.

    2005-01-01

    Roč. 54, č. 4 (2005), s. 395-402 ISSN 0862-8408 Institutional research plan: CEZ:AV0Z5011922 Keywords : ornithine transcarbamoylase * thermal inactivation * shark enzyme Subject RIV: CE - Biochemistry Impact factor: 1.806, year: 2005

  20. Swimming with Sharks: A Physical Educator's Guide to Effective Crowdsourcing

    Science.gov (United States)

    Bulger, Sean M.; Jones, Emily M.; Katz, Nicole; Shrewsbury, Gentry; Wood, Justin

    2016-01-01

    The reality-competition television series Shark Tank affords up-and-coming entrepreneurs the opportunity to make a formal business presentation to a panel of potential investors. Adopting a similar framework, entrepreneurial teachers have started using web-based collaborative fundraising or crowdsourcing as a tool to build program capacity with…

  1. 77 FR 70551 - Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2012-11-26

    ... the acceptable biological catch were not considered part of the statement of work for the stock... timeframe, with the 2008 total allowable catch of 220 metric tons (mt) whole weight (ww) (158.3 mt dressed... probability of rebuilding is the level of success for rebuilding of sharks that was established in the 1999...

  2. Ongoing decline of shark populations in the Eastern Red Sea

    KAUST Repository

    Spaet, Julia L.Y.; Nanninga, Gerrit B.; Berumen, Michael L.

    2016-01-01

    compared to other reef systems around the world. Catch per unit effort values of BRUVs on Sudanese reefs on the contrary were within the range of estimates from various locations where sharks are considered common. We argue that decades of heavy fishing

  3. Geospatial Analysis of Grey Wolf Movement Patterns

    Science.gov (United States)

    Sur, D.

    2017-12-01

    The grey wolf is a top predator that lives across a diverse habitat, ranging from Europe to North America. They often hunt in packs, preferring caribou, deer and elk as prey. Currently, many gray wolves live in Denali National Park and Preserve. In this study, several wolf packs were studied in three distinct regions of Denali. The purpose of my research was to investigate the links between wolf habitat, movement patterns, and prey thresholds. These are needed for projecting future population, growth and distribution of wolves in the studied region. I also investigated the effect wolves have on the ecological structure of the communities they inhabit. In the study I carried out a quantitative analysis of wolf population trends and daily distance movement by utilizing an analysis of variance (ANOVA) in the program JmpPro12 (SAS Institute, Crary, NC) to assess regional differences in pack size, wolf density, average daily distance moved. I found a clear link between the wolf habitat and prey thresholds; the habitat directly influences the types of prey available. However there was no link between the daily distance movement, the wolf habitat and prey density.

  4. ARM Aerial Facility ArcticShark Unmanned Aerial System

    Science.gov (United States)

    Schmid, B.; Hubbell, M.; Mei, F.; Carroll, P.; Mendoza, A.; Ireland, C.; Lewko, K.

    2017-12-01

    The TigerShark Block 3 XP-AR "ArcticShark" Unmanned Aerial System (UAS), developed and manufactured by Navmar Applied Sciences Corporation (NASC), is a single-prop, 60 hp rotary-engine platform with a wingspan of 6.5 m and Maximum Gross Takeoff Weight of 295 Kg. The ArcticShark is owned by the U.S. Department of Energy (DOE) and has been operated by Pacific Northwest National Laboratory (PNNL) since March 2017. The UAS will serve as an airborne atmospheric research observatory for DOE ARM, and, once fully operational, can be requested through ARM's annual call for proposals. The Arctic Shark is anticipated to measure a wide range of radiative, aerosol, and cloud properties using a variable instrument payload weighing up to 46 Kg. SATCOM-equipped, it is capable of taking measurements up to altitudes of 5.5 Km over ranges of up to 500 Km. The ArcticShark operates at airspeeds of 30 to 40 m/s, making it capable of slow sampling. With a full fuel load, its endurance exceeds 8 hours. The aircraft and its Mobile Operations Center (MOC) have been hardened specifically for operations in colder temperatures.ArcticShark's design facilitates rapid integration of various types of payloads. 2500 W of its 4000 W electrical systems is dedicated to payload servicing. It has an interior payload volume of almost 85 L and four wing-mounted pylons capable of carrying external probes. Its payload bay volume, electrical power, payload capacity, and flight characteristics enable the ArcticShark to accommodate multiple combinations of payloads in numerous configurations. Many instruments will be provided by the ARM Aerial Facility (AAF), but other organizations may eventually propose instrumentation for specific campaigns. AAF-provided measurement capabilities will include the following atmospheric state and thermodynamics: temperature, pressure, winds; gases: H2O and CO2; up- and down-welling broadband infrared and visible radiation; surface temperature; aerosol number concentration

  5. Application of entropy measurement technique in grey based ...

    African Journals Online (AJOL)

    For this study, four control variables are selected current, voltage, gas flow rate and ... Keywords: Metal Inert Gas (MIG) Welding, Grey-Taguchi Method, Entropy ...... of metal inert gas welding on the corrosion and mechanical behaviour of.

  6. Breeding biology of African grey parrot (Psittacus erithacus) in Kom ...

    African Journals Online (AJOL)

    3Department of Physiology and Animal Production, Faculty of Agronomy and Agricultural ... Predation (47.37%) was the most important cause of nest failure. ... of conservation actions are essential to avoid future extinction of grey parrots.

  7. Invenio: A Modern Digital Library for Grey Literature

    CERN Document Server

    Caffaro, Jerome

    2010-01-01

    Grey literature has historically played a key role for researchers in the field of High- Energy Physics (HEP). Consequently CERN (European Organization for Nuclear Research) as the world’s largest particle physics laboratory has always been facing the challenge of distributing and archiving grey material. Invenio, an open-source repository software, has been developed as part of CERN’s institutional repository strategy to answer these needs. In this document we describe how the particular context of grey literature within the HEP community shaped the development of Invenio. We focus on the strategies that have been established in order to process grey material within the software and we analyse how it is used in a real production environment, the CERN Document Server (CDS).

  8. A novel field method to distinguish between cryptic carcharhinid sharks, Australian blacktip shark Carcharhinus tilstoni and common blacktip shark C. limbatus, despite the presence of hybrids.

    Science.gov (United States)

    Johnson, G J; Buckworth, R C; Lee, H; Morgan, J A T; Ovenden, J R; McMahon, C R

    2017-01-01

    Multivariate and machine-learning methods were used to develop field identification techniques for two species of cryptic blacktip shark. From 112 specimens, precaudal vertebrae (PCV) counts and molecular analysis identified 95 Australian blacktip sharks Carcharhinus tilstoni and 17 common blacktip sharks Carcharhinus limbatus. Molecular analysis also revealed 27 of the 112 were C. tilstoni × C. limbatus hybrids, of which 23 had C. tilstoni PCV counts and four had C. limbatus PCV counts. In the absence of further information about hybrid phenotypes, hybrids were assigned as either C. limbatus or C. tilstoni based on PCV counts. Discriminant analysis achieved 80% successful identification, but machine-learning models were better, achieving 100% successful identification, using six key measurements (fork length, caudal-fin peduncle height, interdorsal space, second dorsal-fin height, pelvic-fin length and pelvic-fin midpoint to first dorsal-fin insertion). Furthermore, pelvic-fin markings could be used for identification: C. limbatus has a distinct black mark >3% of the total pelvic-fin area, while C. tilstoni has markings with diffuse edges, or has smaller or no markings. Machine learning and pelvic-fin marking identification methods were field tested achieving 87 and 90% successful identification, respectively. With further refinement, the techniques developed here will form an important part of a multi-faceted approach to identification of C. tilstoni and C. limbatus and have a clear management and conservation application to these commercially important sharks. The methods developed here are broadly applicable and can be used to resolve species identities in many fisheries where cryptic species exist. © 2016 The Fisheries Society of the British Isles.

  9. Organic matter and heavy metals in grey-water sludge | Eriksson ...

    African Journals Online (AJOL)

    Grey-water intended for non-potable reuse is being intensively studied, but little attention has been given to the associated solid fraction, the grey-water sludge. In this study grey-water sludge originating from bathroom grey-water has been screened with respect to organic matter; particles; short-chain fatty alcohols and ...

  10. Visual resolution and contrast sensitivity in two benthic sharks.

    Science.gov (United States)

    Ryan, Laura A; Hart, Nathan S; Collin, Shaun P; Hemmi, Jan M

    2016-12-15

    Sharks have long been described as having 'poor' vision. They are cone monochromats and anatomical estimates suggest they have low spatial resolution. However, there are no direct behavioural measurements of spatial resolution or contrast sensitivity. This study estimates contrast sensitivity and spatial resolution of two species of benthic sharks, the Port Jackson shark, Heterodontus portusjacksoni, and the brown-banded bamboo shark, Chiloscyllium punctatum, by recording eye movements in response to optokinetic stimuli. Both species tracked moving low spatial frequency gratings with weak but consistent eye movements. Eye movements ceased at 0.38 cycles per degree, even for high contrasts, suggesting low spatial resolution. However, at lower spatial frequencies, eye movements were elicited by low contrast gratings, 1.3% and 2.9% contrast in H portusjacksoni and C. punctatum, respectively. Contrast sensitivity was higher than in other vertebrates with a similar spatial resolving power, which may reflect an adaptation to the relatively low contrast encountered in aquatic environments. Optokinetic gain was consistently low and neither species stabilised the gratings on their retina. To check whether restraining the animals affected their optokinetic responses, we also analysed eye movements in free-swimming C. punctatum We found no eye movements that could compensate for body rotations, suggesting that vision may pass through phases of stabilisation and blur during swimming. As C. punctatum is a sedentary benthic species, gaze stabilisation during swimming may not be essential. Our results suggest that vision in sharks is not 'poor' as previously suggested, but optimised for contrast detection rather than spatial resolution. © 2016. Published by The Company of Biologists Ltd.

  11. WorldWideScience.org: Bringing Light to Grey

    OpenAIRE

    Hitson, Brian A. (OSTI-DOE); Johnson, Lorrie A. (OSTI-DOE); GreyNet, Grey Literature Network Service

    2008-01-01

    WorldWideScience.org and its governance structure, the WorldWideScience Alliance, are putting a brighter spotlight on grey literature. Through this new tool, grey literature is getting broader exposure to audiences all over the world. Improved access to and sharing of research information is the key to accelerating progress and breakthroughs in any field, especially science. Includes: Conference preprint, Powerpoint presentation, Abstract and Biographical notes, Pratt student commentary ...

  12. Brain grey matter volume alterations in late-life depression.

    Science.gov (United States)

    Du, Mingying; Liu, Jia; Chen, Ziqi; Huang, Xiaoqi; Li, Jing; Kuang, Weihong; Yang, Yanchun; Zhang, Wei; Zhou, Dong; Bi, Feng; Kendrick, Keith M; Gong, Qiyong

    2014-11-01

    Voxel-based morphometry (VBM) studies have demonstrated that grey matter abnormalities are involved in the pathophysiology of late-life depression (LLD), but the findings are inconsistent and have not been quantitatively reviewed. The aim of the present study was to conduct a meta-analysis that integrated the reported VBM studies, to determine consistent grey matter alterations in individuals with LLD. A systematic search was conducted to identify VBM studies that compared patients with LLD and healthy controls. We performed a meta-analysis using the effect size signed differential mapping method to quantitatively estimate regional grey matter abnormalities in patients with LLD. We included 9 studies with 11 data sets comprising 292 patients with LLD and 278 healthy controls in our meta-analysis. The pooled and subgroup meta-analyses showed robust grey matter reductions in the right lentiform nucleus extending into the parahippocampus, the hippocampus and the amygdala, the bilateral medial frontal gyrus and the right subcallosal gyrus as well as a grey matter increase in the right lingual gyrus. Meta-regression analyses showed that mean age and the percentage of female patients with LLD were not significantly related to grey matter changes. The analysis techniques, patient characteristics and clinical variables of the studies included were heterogeneous, and most participants were medicated. The present meta-analysis is, to our knowledge, the first to overcome previous inconsistencies in the VBM studies of LLD and provide robust evidence for grey matter alterations within fronto-striatal-limbic networks, thereby implicating them in the pathophysiology of LLD. The mean age and the percentage of female patients with LLD did not appear to have a measurable impact on grey matter changes, although we cannot rule out the contributory effects of medication.

  13. Rapid isolation of IgNAR variable single-domain antibody fragments from a shark synthetic library.

    Science.gov (United States)

    Shao, Cui-Ying; Secombes, Chris J; Porter, Andrew J

    2007-01-01

    The immunoglobulin isotype IgNAR (Novel Antigen Receptor) was discovered in the serum of the nurse shark (Ginglymostoma cirratum) and wobbegong shark (Orectolobus maculates) as a homodimer of two protein chains, each composed of a single variable domain (V) domain and five constant domains. The IgNAR variable domain contains an intact antigen-binding site and functions as an independent domain able to react to antigen with both high specificity and affinity. Here we describe the successful construction of a synthetic phage-displayed library based upon a single anti-lysozyme clone HEL-5A7 scaffold, which was previously selected from an immune IgNAR variable domain library. The complementarity-determining region 3 (CDR3) loop of this clone was varied in both length and composition and the derived library was used to pan against two model proteins, lysozyme and leptin. A single anti-lysozyme clone (Ly-X20) and anti-leptin clone (Lep-12E1) were selected for further study. Both clones were shown to be functionally expressed in Escherichia coli, extremely thermostable and bind to corresponding antigens specifically. The results here demonstrate that a synthetic IgNAR variable domain library based on a single framework scaffold can be used as a route to generate antigen binders quickly, easily and without the need of immunization.

  14. Habitat features influence catch rates of near-shore bull shark (Carcharhinus leucas) in the Queensland Shark Control Program, Australia 1996-2012

    Science.gov (United States)

    Haig, Jodie A.; Lambert, Gwladys I.; Sumpton, Wayne D.; Mayer, David G.; Werry, Jonathan M.

    2018-01-01

    Understanding shark habitat use is vital for informing better ecological management of coastal areas and shark populations. The Queensland Shark Control Program (QSCP) operates over ∼1800 km of Queensland coastline. Between 1996 and 2012, catch, total length and sex were recorded from most of the 1992 bull shark (Carcharhinus leucas) caught on drum lines and gill-nets as part of the QSCP (sex and length was not successfully recorded for all individuals). Gear was set at multiple sites within ten locations. Analysis of monthly catch data resulted in a zero-inflated dataset for the 17 years of records. Five models were trialled for suitability of standardising the bull shark catch per unit effort (CPUE) using available habitat and environmental data. Three separate models for presence-absence and presence-only were run and outputs combined using a delta-lognormal framework for generalized linear and generalized additive models. The delta-lognormal generalized linear model approach resulted in best fit to explain patterns in CPUE. Greater CPUE occurred on drum lines, and greater numbers of bull sharks were caught on both gear types in summer months, with tropical sites, and sites with greater adjacent wetland habitats catching consistently more bull sharks compared to sub-tropical sites. The CPUE data did not support a hypothesis of population decline indicative of coastal overfishing. However, the total length of sharks declined slightly through time for those caught in the tropics; subtropical catches were dominated by females and a large proportion of all bull sharks caught were smaller than the size-at-maturity reported for this species. These factors suggest that growth and sex overfishing of Queensland bull shark populations may be occurring but are not yet detectable in the available data. The data highlight available coastal wetlands, river size, length of coastline and distance to the 50 m depth contour are important for consideration in future whole of

  15. Multiple prismatic calcium phosphate layers in the jaws of present-day sharks (Chondrichthyes; Selachii).

    Science.gov (United States)

    Dingerkus, G; Séret, B; Guilbert, E

    1991-01-15

    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 prismatic calcium phosphate surrounding the cartilages, as also do most species of fossil chondrichthyans. Two exceptions are the fossil shark genera Xenacanthus and Tamiobatis. Where it is found in living forms, this multiple layered calcification does not appear to be phylogenetic, as it appears to be lacking in other lamnid and carcharhinid genera and species. Rather it appears to be functional, only appearing in larger individuals and species of these two groups, and hence may be necessary to strengthen the jaw cartilages of such individuals for biting.

  16. Greenland sharks (Somniosus microcephalus scavenge offal from minke (Balaenoptera acutorostrata whaling operations in Svalbard (Norway

    Directory of Open Access Journals (Sweden)

    Lisa-Marie Leclerc

    2011-06-01

    Full Text Available Minke whale (Balaenoptera acutorostrata tissue (mainly blubber was found in the gastrointestinal tracks of Greenland sharks (Somniosus microcephalus collected in Kongsfjorden, Svalbard, Norway. In order to determine whether the sharks were actively hunting the whales, finding naturally dead whales or consuming offal from whaling, we checked the genetic identity of the whale tissue found in the sharks against the DNA register for minke whales taken in Norwegian whaling operations. All of the minke whale samples from the sharks that had DNA of sufficient quality to perform individual identifications were traceable to the whaling DNA register. During whaling operations, the blubber is stripped from the carcass and thrown overboard. The blubber strips float on the surface and are available for surface-feeding predators. This study revealed that Greenland sharks are scavenging this material; additionally, it demonstrates the capacity of this ‘benthic-feeding’ shark to utilize the whole water column for foraging.

  17. Quantitative and qualitative analysis of fluoride and multi elements of shark teeth by PIXE

    International Nuclear Information System (INIS)

    Sakurai, S.; Asakawa, R.; Hirota, F.; Sato, T.; Sera, K.; Itoh, J.

    2008-01-01

    Biomineralization has two types, biologically induced mineralization (BIM) and biologically controlled mineralization (BCM). Shark teeth is a typical representative of BCM. We have measured concentrations of fluorine and multi elements in shark teeth collected in the south of Japan. As a result, it was confirmed that the sample preparation method, which was established for the biological samples, is applicable to the shark teeth samples and the elemental concentration was obtained in good accuracy and reproducibility. Moreover, we clarified that the shark teeth is composed of Fluorapatite by the combination with X-ray Diffraction. Fluorine concentration is found to be 5500 μg/g in the shark teeth. We have 100 samples of Shark teeth and are planning on reporting the findings of a study with larger samples in the near future. (author)

  18. Do White Shark Bites on Surfers Reflect Their Attack Strategies on Pinnipeds?

    Directory of Open Access Journals (Sweden)

    Erich Ritter

    2016-01-01

    Full Text Available The theory of mistaken identity states that sharks, especially white sharks, Carcharodon carcharias, mistake surfers for pinnipeds when looking at them from below and thus bite them erroneously. Photographs of surfer wounds and board damage were interpreted with special emphasis on shark size, wound severity, and extent of damage to a board. These were compared with the concurrent literature on attack strategies of white sharks on pinnipeds and their outcomes. The results show that the majority of damage to surfers and their boards is at best superficial-to-moderate in nature and does not reflect the level of damage needed to immobilize or stun a pinniped. It is further shown that the size distribution of sharks biting surfers differs from that in pinnipeds. The results presented show that the theory of mistaken identity, where white sharks erroneously mistake surfers for pinnipeds, does not hold true and should be rejected.

  19. Growth and maximum size of tiger sharks (Galeocerdo cuvier) in Hawaii.

    Science.gov (United States)

    Meyer, Carl G; O'Malley, Joseph M; Papastamatiou, Yannis P; Dale, Jonathan J; Hutchinson, Melanie R; Anderson, James M; Royer, Mark A; Holland, Kim N

    2014-01-01

    Tiger sharks (Galecerdo cuvier) are apex predators characterized by their broad diet, large size and rapid growth. Tiger shark maximum size is typically between 380 & 450 cm Total Length (TL), with a few individuals reaching 550 cm TL, but the maximum size of tiger sharks in Hawaii waters remains uncertain. A previous study suggested tiger sharks grow rather slowly in Hawaii compared to other regions, but this may have been an artifact of the method used to estimate growth (unvalidated vertebral ring counts) compounded by small sample size and narrow size range. Since 1993, the University of Hawaii has conducted a research program aimed at elucidating tiger shark biology, and to date 420 tiger sharks have been tagged and 50 recaptured. All recaptures were from Hawaii except a single shark recaptured off Isla Jacques Cousteau (24°13'17″N 109°52'14″W), in the southern Gulf of California (minimum distance between tag and recapture sites  =  approximately 5,000 km), after 366 days at liberty (DAL). We used these empirical mark-recapture data to estimate growth rates and maximum size for tiger sharks in Hawaii. We found that tiger sharks in Hawaii grow twice as fast as previously thought, on average reaching 340 cm TL by age 5, and attaining a maximum size of 403 cm TL. Our model indicates the fastest growing individuals attain 400 cm TL by age 5, and the largest reach a maximum size of 444 cm TL. The largest shark captured during our study was 464 cm TL but individuals >450 cm TL were extremely rare (0.005% of sharks captured). We conclude that tiger shark growth rates and maximum sizes in Hawaii are generally consistent with those in other regions, and hypothesize that a broad diet may help them to achieve this rapid growth by maximizing prey consumption rates.

  20. Residency and movement patterns of an apex predatory shark (Galeocerdo cuvier at the Galapagos Marine Reserve.

    Directory of Open Access Journals (Sweden)

    David Acuña-Marrero

    Full Text Available The potential effectiveness of marine protected areas (MPAs as a conservation tool for large sharks has been questioned due to the limited spatial extent of most MPAs in contrast to the complex life history and high mobility of many sharks. Here we evaluated the movement dynamics of a highly migratory apex predatory shark (tiger shark Galeocerdo cuvier at the Galapagos Marine Reserve (GMR. Using data from satellite tracking passive acoustic telemetry, and stereo baited remote underwater video, we estimated residency, activity spaces, site fidelity, distributional abundances and migration patterns from the GMR and in relation to nesting beaches of green sea turtles (Chelonia mydas, a seasonally abundant and predictable prey source for large tiger sharks. Tiger sharks exhibited a high degree of philopatry, with 93% of the total satellite-tracked time across all individuals occurring within the GMR. Large sharks (> 200 cm TL concentrated their movements in front of the two most important green sea turtle-nesting beaches in the GMR, visiting them on a daily basis during nocturnal hours. In contrast, small sharks (< 200 cm TL rarely visited turtle-nesting areas and displayed diurnal presence at a third location where only immature sharks were found. Small and some large individuals remained in the three study areas even outside of the turtle-nesting season. Only two sharks were satellite-tracked outside of the GMR, and following long-distance migrations, both individuals returned to turtle-nesting beaches at the subsequent turtle-nesting season. The spatial patterns of residency and site fidelity of tiger sharks suggest that the presence of a predictable source of prey and suitable habitats might reduce the spatial extent of this large shark that is highly migratory in other parts of its range. This highly philopatric behaviour enhances the potential effectiveness of the GMR for their protection.

  1. Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama

    OpenAIRE

    Pimiento, Catalina; Ehret, Dana J.; MacFadden, Bruce J.; Hubbell, Gordon

    2010-01-01

    BACKGROUND: As we know from modern species, nursery areas are essential shark habitats for vulnerable young. Nurseries are typically highly productive, shallow-water habitats that are characterized by the presence of juveniles and neonates. It has been suggested that in these areas, sharks can find ample food resources and protection from predators. Based on the fossil record, we know that the extinct Carcharocles megalodon was the biggest shark that ever lived. Previous proposed paleo-nurser...

  2. Tiger sharks can connect equatorial habitats and fisheries across the Atlantic Ocean basin.

    Science.gov (United States)

    Afonso, André S; Garla, Ricardo; Hazin, Fábio H V

    2017-01-01

    Increasing our knowledge about the spatial ecology of apex predators and their interactions with diverse habitats and fisheries is necessary for understanding the trophic mechanisms that underlie several aspects of marine ecosystem dynamics and for guiding informed management policies. A preliminary assessment of tiger shark (Galeocerdo cuvier) population structure off the oceanic insular system of Fernando de Noronha (FEN) and the large-scale movements performed by this species in the equatorial Atlantic Ocean was conducted using longline and handline fishing gear and satellite telemetry. A total of 25 sharks measuring 175-372 cm in total length (TL) were sampled. Most sharks were likely immature females ranging between 200 and 260 cm TL, with few individuals shark size-distribution previously reported for coastal waters off the Brazilian mainland, where most individuals measured shark-1; SD = 65.6). These sharks exhibited a considerable variability in their horizontal movements, with three sharks showing a mostly resident behavior around FEN during the extent of the respective tracks, two sharks traveling west to the South American continent, and two sharks moving mostly along the middle of the oceanic basin, one of which ending up in the northern hemisphere. Moreover, one shark traveled east to the African continent, where it was eventually caught by fishers from Ivory Coast in less than 474 days at liberty. The present results suggest that young tiger sharks measuring sharks are able to connect marine trophic webs from the neritic provinces of the eastern and western margins of the Atlantic Ocean across the equatorial basin and that they may experience mortality induced by remote fisheries. All this information is extremely relevant for understanding the energetic balance of marine ecosystems as much as the exposure of this species to fishing pressure in this yet poorly-known region.

  3. Impact of biology knowledge on the conservation and management of large pelagic sharks

    OpenAIRE

    Yokoi, Hiroki; Ijima, Hirotaka; Ohshimo, Seiji; Yokawa, Kotaro

    2017-01-01

    Population growth rate, which depends on several biological parameters, is valuable information for the conservation and management of pelagic sharks, such as blue and shortfin mako sharks. However, reported biological parameters for estimating the population growth rates of these sharks differ by sex and display large variability. To estimate the appropriate population growth rate and clarify relationships between growth rate and relevant biological parameters, we developed a two-sex age-str...

  4. Big catch, little sharks: Insight into Peruvian small-scale longline fisheries

    OpenAIRE

    Doherty, Philip D; Alfaro-Shigueto, Joanna; Hodgson, David J; Mangel, Jeffrey C; Witt, Matthew J; Godley, Brendan J

    2014-01-01

    Shark take, driven by vast demand for meat and fins, is increasing. We set out to gain insights into the impact of small-scale longline fisheries in Peru. Onboard observers were used to document catch from 145 longline fishing trips (1668 fishing days) originating from Ilo, southern Peru. Fishing effort is divided into two seasons: targeting dolphinfish (Coryphaena hippurus; December to February) and sharks (March to November). A total of 16,610 sharks were observed caught, with 11,166 identi...

  5. First record of the blacktip reef shark Carcharhinus melanopterus (Carcharhiniformes: Carcharhinidae from the Tropical Eastern Pacific

    Directory of Open Access Journals (Sweden)

    Andrés López-Garro

    2012-11-01

    Full Text Available The blacktip reef shark Carcharhinus melanopterus, is one of the most common Indo-Pacific reef sharks. On April 29, 2012, a juvenile male blacktip reef shark measuring 89 cm total length (TL, was incidentally caught during a research expedition in Chatham Bay, Isla del Coco National Park, Costa Rica, located in the Tropical Eastern Pacific. This is the first record of the species from Isla del Coco National Park, Costa Rica, and from the Tropical Eastern Pacific.

  6. GreyGuide Portal and Repositories "Sharing knowledge as early as possible"

    OpenAIRE

    Biagioni, Stefania; Carlesi, Carlo; Barsotti, Alessia; Pardini, Andrea

    2017-01-01

    The GreyGuide - Repository and Guide to Good Practices and Resources in Grey Literature was launched in 2013 as a collaborative effort between GreyNet International and ISTI-CNR. It aims at ?. Offering information professionals, practitioners, and students common ground for good practices and resources in grey literature; ?. Providing support for all stakeholders working on Grey Literature related research issues; ?. Being consistent with recommendations made in the Pisa Declaration on Policy...

  7. Putative Adult Neurogenesis in Old World Parrots: The Congo African Grey Parrot (Psittacus erithacus) and Timneh Grey Parrot (Psittacus timneh).

    Science.gov (United States)

    Mazengenya, Pedzisai; Bhagwandin, Adhil; Manger, Paul R; Ihunwo, Amadi O

    2018-01-01

    In the current study, we examined for the first time, the potential for adult neurogenesis throughout the brain of the Congo African grey parrot ( Psittacus erithacus ) and Timneh grey parrot ( Psittacus timneh ) using immunohistochemistry for the endogenous markers proliferating cell nuclear antigen (PCNA), which labels proliferating cells, and doublecortin (DCX), which stains immature and migrating neurons. A similar distribution of PCNA and DCX immunoreactivity was found throughout the brain of the Congo African grey and Timneh grey parrots, but minor differences were also observed. In both species of parrots, PCNA and DCX immunoreactivity was observed in the olfactory bulbs, subventricular zone of the lateral wall of the lateral ventricle, telencephalic subdivisions of the pallium and subpallium, diencephalon, mesencephalon and the rhombencephalon. The olfactory bulb and telencephalic subdivisions exhibited a higher density of both PCNA and DCX immunoreactive cells than any other brain region. DCX immunoreactive staining was stronger in the telencephalon than in the subtelencephalic structures. There was evidence of proliferative hot spots in the dorsal and ventral poles of the lateral ventricle in the Congo African grey parrots at rostral levels, whereas only the dorsal accumulation of proliferating cells was observed in the Timneh grey parrot. In most pallial regions the density of PCNA and DCX stained cells increased from rostral to caudal levels with the densest staining in the nidopallium caudolaterale (NCL). The widespread distribution of PCNA and DCX in the brains of both parrot species suggest the importance of adult neurogenesis and neuronal plasticity during learning and adaptation to external environmental variations.

  8. An EGR performance evaluation and decision-making approach based on grey theory and grey entropy analysis.

    Science.gov (United States)

    Zu, Xianghuan; Yang, Chuanlei; Wang, Hechun; Wang, Yinyan

    2018-01-01

    Exhaust gas recirculation (EGR) is one of the main methods of reducing NOX emissions and has been widely used in marine diesel engines. This paper proposes an optimized comprehensive assessment method based on multi-objective grey situation decision theory, grey relation theory and grey entropy analysis to evaluate the performance and optimize rate determination of EGR, which currently lack clear theoretical guidance. First, multi-objective grey situation decision theory is used to establish the initial decision-making model according to the main EGR parameters. The optimal compromise between diesel engine combustion and emission performance is transformed into a decision-making target weight problem. After establishing the initial model and considering the characteristics of EGR under different conditions, an optimized target weight algorithm based on grey relation theory and grey entropy analysis is applied to generate the comprehensive evaluation and decision-making model. Finally, the proposed method is successfully applied to a TBD234V12 turbocharged diesel engine, and the results clearly illustrate the feasibility of the proposed method for providing theoretical support and a reference for further EGR optimization.

  9. Grey water characterisation and pollutant loads in an urban slum

    International Nuclear Information System (INIS)

    Katukiza, A. Y.; Ronteltap, M.; Niwagaba, C. B.; Kansiime, F.; Lens, P. N. L.

    2015-01-01

    On-site sanitation provisions in urban slums rarely prioritise grey water management, yet it forms the largest fraction of wastewater. This study was carried out to characterise grey water and quantify its pollutant loads in Bwaise III (Uganda) and to provide data for grey water management in urban slums of developing countries. Samples were collected for analysis from ten representative households as well as from four tertiary drains and the main drainage channel for 7 months in two dry seasons. Grey water production was found to comprise 85 % of the domestic water consumption. The chemical oxygen demand concentration in the grey water generated by laundry, in the kitchen and in the bathroom was 9,225 ± 1,200 mg L-1, 71,250 ± 1,011 mg L-1 and 4,675 ± 750 mg L-1, while the BOD5 (biochemical oxygen demand) to COD ratio was 0.24 ± 0.05, 0.33 ± 0.08 and 0.31 ± 0.07, respectively. The maximum concentration of Escherichia coli and total coliforms was 2.05 9 107 cfu (100 mL)-1 and 1.75 9 108 cfu (100 mL)-1, respectively, in grey water from the bathroom, while that of Salmonella spp. was 7.32 9 106 cfu (100 mL)-1 from laundry. Analysis of variance (ANOVA) showed a significant difference in the concentration of COD, total suspended solids, total organic carbon, dissolved organic carbon, total phosphorus, sodium adsorption ratio, oil and grease, and Salmonella spp. in grey water from laundry, bathroom and kitchen (p/0.05). The high loads of COD ([500 kg day-1), total suspended solids ([200 kg day-1), nutrients (8.3 kg TKN day-1 and 1.4 kg total phosphorus day-1) and microorganisms (106 to 109 cfu c-1 day-1) originating from grey water in Bwaise III show that grey water poses a threat to the environment and a risk to human health in urban slums. Therefore, there is a need to prioritise grey water treatment in urban slums of developing countries to achieve adequate sanitation.

  10. Widespread utility of highly informative AFLP molecular markers across divergent shark species.

    Science.gov (United States)

    Zenger, Kyall R; Stow, Adam J; Peddemors, Victor; Briscoe, David A; Harcourt, Robert G

    2006-01-01

    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 polymorphism method that can be applied universally to sharks to identify highly informative genome-wide polymorphisms from 12 primer pairs. We demonstrate the value of our method on 15 divergent shark species within the superorder Galeomorphii, including endangered species which are notorious for low levels of genetic diversity. Both the endangered sand tiger shark (Carcharodon taurus, N = 18) and the great white shark (Carcharodon carcharias, N = 7) displayed relatively high levels of allelic diversity. A total of 59 polymorphic loci (H(e) = 0.373) and 78 polymorphic loci (H(e) = 0.316) were resolved in C. taurus and C. carcharias, respectively. Results from other sharks (e.g., Orectolobus ornatus, Orectolobus sp., and Galeocerdo cuvier) produced remarkably high numbers of polymorphic loci (106, 94, and 86, respectively) from a limited sample size of only 2. A major constraint to obtaining much needed genetic data from sharks is the time-consuming process of developing molecular markers. Here we demonstrate the general utility of a technique that provides large numbers of informative loci in sharks.

  11. Survey sequencing and comparative analysis of the elephant shark (Callorhinchus milii genome.

    Directory of Open Access Journals (Sweden)

    Byrappa Venkatesh

    2007-04-01

    Full Text Available Owing to their phylogenetic position, cartilaginous fishes (sharks, rays, skates, and chimaeras provide a critical reference for our understanding of vertebrate genome evolution. The relatively small genome of the elephant shark, Callorhinchus milii, a chimaera, makes it an attractive model cartilaginous fish genome for whole-genome sequencing and comparative analysis. Here, the authors describe survey sequencing (1.4x coverage and comparative analysis of the elephant shark genome, one of the first cartilaginous fish genomes to be sequenced to this depth. Repetitive sequences, represented mainly by a novel family of short interspersed element-like and long interspersed element-like sequences, account for about 28% of the elephant shark genome. Fragments of approximately 15,000 elephant shark genes reveal specific examples of genes that have been lost differentially during the evolution of tetrapod and teleost fish lineages. Interestingly, the degree of conserved synteny and conserved sequences between the human and elephant shark genomes are higher than that between human and teleost fish genomes. Elephant shark contains putative four Hox clusters indicating that, unlike teleost fish genomes, the elephant shark genome has not experienced an additional whole-genome duplication. These findings underscore the importance of the elephant shark as a critical reference vertebrate genome for comparative analysis of the human and other vertebrate genomes. This study also demonstrates that a survey-sequencing approach can be applied productively for comparative analysis of distantly related vertebrate genomes.

  12. Essential and non-essential element concentrations in two sleeper shark species collected in arctic waters

    Energy Technology Data Exchange (ETDEWEB)

    McMeans, Bailey C. [Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4 (Canada); Borga, Katrine [Norwegian Institute for Water Research, P.O. Box 173, Kjelsas, N-0411 Oslo (Norway); Bechtol, William R. [Alaska Department of Fish and Game, Division of Commercial Fisheries, Anchorage, AK 99518-1599 (United States); Higginbotham, David [Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602-2152 (United States); Fisk, Aaron T. [Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4 (Canada)]. E-mail: afisk@uwindsor.ca

    2007-07-15

    A number of elements/metals have increased in arctic biota and are of concern due to their potential toxicity. Most studies on elements in the Arctic have focused on marine mammals and seabirds, but concentrations in the Greenland shark (Somniosus microcephalus) and Pacific sleeper shark (Somniosus pacificus), the only two shark species known to regularly inhabit arctic waters, have never been reported. To address this data gap, concentrations and patterns of 25 elements were analyzed in liver of Greenland sharks collected about Cumberland Sound (n = 24) and Pacific sleeper sharks collected about Prince William Sound (n = 14). Several non-essential elements differed between species/locations, which could suggest geographical exposure differences or ecological (e.g., diet) differences between the species. Certain essential elements also differed between the two sleeper sharks, which may indicate different physiological requirements between these closely related shark species, although information on such relationships are lacking for sharks and fish. - Patterns of essential and non-essential elements provide insight into sleeper shark biology and physiology.

  13. Essential and non-essential element concentrations in two sleeper shark species collected in arctic waters

    International Nuclear Information System (INIS)

    McMeans, Bailey C.; Borga, Katrine; Bechtol, William R.; Higginbotham, David; Fisk, Aaron T.

    2007-01-01

    A number of elements/metals have increased in arctic biota and are of concern due to their potential toxicity. Most studies on elements in the Arctic have focused on marine mammals and seabirds, but concentrations in the Greenland shark (Somniosus microcephalus) and Pacific sleeper shark (Somniosus pacificus), the only two shark species known to regularly inhabit arctic waters, have never been reported. To address this data gap, concentrations and patterns of 25 elements were analyzed in liver of Greenland sharks collected about Cumberland Sound (n = 24) and Pacific sleeper sharks collected about Prince William Sound (n = 14). Several non-essential elements differed between species/locations, which could suggest geographical exposure differences or ecological (e.g., diet) differences between the species. Certain essential elements also differed between the two sleeper sharks, which may indicate different physiological requirements between these closely related shark species, although information on such relationships are lacking for sharks and fish. - Patterns of essential and non-essential elements provide insight into sleeper shark biology and physiology

  14. What the shark immune system can and cannot provide for the expanding design landscape of immunotherapy.

    Science.gov (United States)

    Criscitiello, Michael F

    2014-07-01

    Sharks have successfully lived in marine ecosystems, often atop food chains as apex predators, for nearly one and a half billion years. Throughout this period they have benefitted from an immune system with the same fundamental components found in terrestrial vertebrates like man. Additionally, sharks have some rather extraordinary immune mechanisms which mammals lack. In this review the author briefly orients the reader to sharks, their adaptive immunity, and their important phylogenetic position in comparative immunology. The author also differentiates some of the myths from facts concerning these animals, their cartilage, and cancer. From thereon, the author explores some of the more remarkable capabilities and products of shark lymphocytes. Sharks have an isotype of light chain-less antibodies that are useful tools in molecular biology and are moving towards translational use in the clinic. These special antibodies are just one of the several tricks of shark lymphocyte antigen receptor systems. While shark cartilage has not helped oncology patients, shark immunoglobulins and T cell receptors do offer exciting novel possibilities for immunotherapeutics. Much of the clinical immunology developmental pipeline has turned from traditional vaccines to passively delivered monoclonal antibody-based drugs for targeted depletion, activation, blocking and immunomodulation. The immunogenetic tools of shark lymphocytes, battle-tested since the dawn of our adaptive immune system, are well poised to expand the design landscape for the next generation of immunotherapy products.

  15. Australian and U.S. news media portrayal of sharks and their conservation.

    Science.gov (United States)

    Muter, Bret A; Gore, Meredith L; Gledhill, Katie S; Lamont, Christopher; Huveneers, Charlie

    2013-02-01

    Investigation of the social framing of human-shark interactions may provide useful strategies for integrating social, biological, and ecological knowledge into national and international policy discussions about shark conservation. One way to investigate social opinion and forces related to sharks and their conservation is through the media's coverage of sharks. We conducted a content analysis of 300 shark-related articles published in 20 major Australian and U.S. newspapers from 2000 to 2010. Shark attacks were the emphasis of over half the articles analyzed, and shark conservation was the primary topic of 11% of articles. Significantly more Australian articles than U.S. articles treated shark attacks (χ(2) = 3.862; Australian 58% vs. U.S. 47%) and shark conservation issues (χ(2) = 6.856; Australian 15% vs. U.S. 11%) as the primary article topic and used politicians as the primary risk messenger (i.e., primary person or authority sourced in the article) (χ(2) = 7.493; Australian 8% vs. U.S. 1%). However, significantly more U.S. articles than Australian articles discussed sharks as entertainment (e.g., subjects in movies, books, and television; χ(2) = 15.130; U.S. 6% vs. Australian 1%) and used scientists as the primary risk messenger (χ(2) = 5.333; U.S. 25% vs. Australian 15%). Despite evidence that many shark species are at risk of extinction, we found that most media coverage emphasized the risks sharks pose to people. To the extent that media reflects social opinion, our results highlight problems for shark conservation. We suggest that conservation professionals purposefully and frequently engage with the media to highlight the rarity of shark attacks, discuss preventative measures water users can take to reduce their vulnerability to shark encounters, and discuss conservation issues related to local and threatened species of sharks. When integrated with biological and ecological data, social-science data may help generate a more comprehensive perspective

  16. Ultrastructure Organization of Collagen Fibrils and Proteoglycans of Stingray and Shark Corneal Stroma

    Directory of Open Access Journals (Sweden)

    Saud A. Alanazi

    2015-01-01

    Full Text Available We report here the ultrastructural organization of collagen fibrils (CF and proteoglycans (PGs of the corneal stroma of both the stingray and the shark. Three corneas from three stingrays and three corneas from three sharks were processed for electron microscopy. Tissues were embedded in TAAB 031 resin. The corneal stroma of both the stingray and shark consisted of parallel running lamellae of CFs which were decorated with PGs. In the stingray, the mean area of PGs in the posterior stroma was significantly larger than the PGs of the anterior and middle stroma, whereas, in the shark, the mean area of PGs was similar throughout the stroma. The mean area of PGs of the stingray was significantly larger compared to the PGs, mean area of the shark corneal stroma. The CF diameter of the stingray was significantly smaller compared to the CF diameter in the shark. The ultrastructural features of the corneal stroma of both the stingray and the shark were similar to each other except for the CFs and PGs. The PGs in the stingray and shark might be composed of chondroitin sulfate (CS/dermatan sulfate (DS PGs and these PGs with sutures might contribute to the nonswelling properties of the cornea of the stingray and shark.

  17. [Trophic niche partitioning of pelagic sharks in Central Eastern Pacific inferred from stable isotope analysis.

    Science.gov (United States)

    Li, Yun Kai; Gao, Xiao di; Wang, Lin Yu; Fang, Lin

    2018-01-01

    As the apex predators of the open ocean ecosystems, pelagic sharks play important roles in stabilizing the marine food web through top-down control. Stable isotope analysis is a powerful tool to investigate the feeding ecology. The carbon and nitrogen isotope ratios can be used to trace food source and evaluate the trophic position of marine organisms. In this study, the isotope values of 130 pelagic sharks from 8 species in Central Eastern Pacific were analyzed and their trophic position and niche were calculated to compare the intra/inter-specific resource partitioning in the Central Eastern Pacific ecosystem. The results exhibited significant differences in both carbon and nitrogen isotope values among the shark species. The trophic levels ranged from 4.3 to 5.4 in the Central Eastern Pacific shark community. The trophic niche of blue sharks and shortfin mako sharks showed no overlap with the other shark species, exhibiting unique ecological roles in the open ocean food web. These data highlighted the diverse roles among pelagic sharks, supporting previous findings that this species is not trophically redundant and the trophic niche of pelagic sharks can not be simply replaced by those of other top predator species.

  18. A streamlined DNA tool for global identification of heavily exploited coastal shark species (genus Rhizoprionodon.

    Directory of Open Access Journals (Sweden)

    Danillo Pinhal

    Full Text Available Obtaining accurate species-specific landings data is an essential step toward achieving sustainable shark fisheries. Globally distributed sharpnose sharks (genus Rhizoprionodon exhibit life-history characteristics (rapid growth, early maturity, annual reproduction that suggests that they could be fished in a sustainable manner assuming an investment in monitoring, assessment and careful management. However, obtaining species-specific landings data for sharpnose sharks is problematic because they are morphologically very similar to one another. Moreover, sharpnose sharks may also be confused with other small sharks (either small species or juveniles of large species once they are processed (i.e., the head and fins are removed. Here we present a highly streamlined molecular genetics approach based on seven species-specific PCR primers in a multiplex format that can simultaneously discriminate body parts from the seven described sharpnose shark species commonly occurring in coastal fisheries worldwide. The species-specific primers are based on nucleotide sequence differences among species in the nuclear ribosomal internal transcribed spacer 2 locus (ITS2. This approach also distinguishes sharpnose sharks from a wide range of other sharks (52 species and can therefore assist in the regulation of coastal shark fisheries around the world.

  19. Postrelease survival, vertical and horizontal movements, and thermal habitats of five species of pelagic sharks in the central Pacific Ocean

    DEFF Research Database (Denmark)

    Musyl, Michael K.; Brill, Richard W.; Curran, Daniel S.

    2011-01-01

    ]) in the central Pacific Ocean to determine speciesspecific movement patterns and survival rates after release from longline fishing gear. Only a single postrelease mortality could be unequivocally documented: a male blue shark which succumbed seven days after release. Meta-analysis of published reports......From 2001 to 2006, 71 pop-up satellite archival tags (PSATs) were deployed on five species of pelagic shark (blue shark [Prionace glauca]; shortfin mako [Isurus oxyrinchus]; silky shark [Carcharhinus falciformis]; oceanic whitetip shark [C. longimanus]; and bigeye thresher [Alopias superciliosus...... and the current study (n=78 reporting PSATs) indicated that the summary effect of postrelease mortality for blue sharks was 15% (95% CI, 8.5-25.1%) and suggested that catch-and-release in longline fisheries can be a viable management tool to protect parental biomass in shark populations. Pelagic sharks displayed...

  20. Genetic structure of populations of whale sharks among ocean basins and evidence for their historic rise and recent decline

    KAUST Repository

    Vignaud, Thomas M.; Maynard, Jeffrey Allen; Leblois, Raphaë l; Meekan, Mark G.; Vá zquez-Juá rez, Ricardo; Ramí rez-Mací as, Dení ; Pierce, Simon J.; Rowat, David; Berumen, Michael L.; Beeravolu, Champak R.; Baksay, Sandra; Planes, Serge

    2014-01-01

    This study presents genetic evidence that whale sharks, Rhincodon typus, are comprised of at least two populations that rarely mix and is the first to document a population expansion. Relatively high genetic structure is found when comparing sharks

  1. Fine-Scale Movements and Behaviors of Whale Sharks, Rhincodon typus, in a Seasonal Aggregation near Al Lith, Saudi Arabia

    KAUST Repository

    Sun, Lu

    2016-01-01

    . In another dimension, depth use of whale sharks derived from biologgers showed distinct diel patterns. The sharks heavily utilized shallow waters with mixed depth usage consisting of surface swimming and varied types of dives, which explained the data

  2. Assessment of global grey water footprint of major food crops

    Science.gov (United States)

    Yang, Hong; Liu, Wenfeng; Antonelli, Marta

    2016-04-01

    Agricultural production is one of the major sources of water pollution in the world. This is closely related to the excess application of fertilizers. Leaching of N and P to water bodies has caused serious degradation of water quality in many places. With the persistent increase in the demand for agricultural products, agricultural intensification evident during the past decades will continue in the future. This will lead to further increase in fertilizer application and consequently water pollution. Grey water footprint is a measure of the intensity of water pollution caused by water use for human activities. It is defined as the volume of water that is required to assimilate a load of pollutants to a freshwater body, based on natural background concentrations and water quality standards. This study conducts a global assessment of grey water footprint for major cereal crops, wheat, maize and rice. A crop model, Python-based EPIC (PEPIT), is applied to quantify the leaching of N and P from the fertilizer application in the three crops on a global scale with 0.5 degree spatial resolution. The hotspots of leaching are identified. The results suggest that, based on the definition and method of grey water footprint proposed by the World Water Footprint Network, the grey water footprint in many parts of the world has exceeded their total water resources availability. This indicates the seriousness of water pollution caused by agricultural production. However, the situation may also call for the development of a realistic measurement of grey water footprint which is more pertinent to water resources management. This paper proposes some alternatives in measuring grey water footprint and also discusses incorporation of grey water footprint assessment into water policy formulation and river basins plan development.

  3. Relationship between grey matter integrity and executive abilities in aging.

    Science.gov (United States)

    Manard, Marine; Bahri, Mohamed Ali; Salmon, Eric; Collette, Fabienne

    2016-07-01

    This cross-sectional study was designed to investigate grey matter changes that occur in healthy aging and the relationship between grey matter characteristics and executive functioning. Thirty-six young adults (18-30 years old) and 43 seniors (60-75 years old) were included. A general executive score was derived from a large battery of neuropsychological tests assessing three major aspects of executive functioning (inhibition, updating and shifting). Age-related grey matter changes were investigated by comparing young and older adults using voxel-based morphometry and voxel-based cortical thickness methods. A widespread difference in grey matter volume was found across many brain regions, whereas cortical thinning was mainly restricted to central areas. Multivariate analyses showed age-related changes in relatively similar brain regions to the respective univariate analyses but appeared more limited. Finally, in the older adult sample, a significant relationship between global executive performance and decreased grey matter volume in anterior (i.e. frontal, insular and cingulate cortex) but also some posterior brain areas (i.e. temporal and parietal cortices) as well as subcortical structures was observed. Results of this study highlight the distribution of age-related effects on grey matter volume and show that cortical atrophy does not appear primarily in "frontal" brain regions. From a cognitive viewpoint, age-related executive functioning seems to be related to grey matter volume but not to cortical thickness. Therefore, our results also highlight the influence of methodological aspects (from preprocessing to statistical analysis) on the pattern of results, which could explain the lack of consensus in literature. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. 'Living a life in shades of grey': experiencing depressive symptoms in the acute phase after stroke.

    Science.gov (United States)

    Kouwenhoven, Siren E; Kirkevold, Marit; Engedal, Knut; Kim, Hesook S

    2012-08-01

    The aim of the present study was to describe the lived experience of stroke survivors suffering from depressive symptoms in the acute phase; addressing the following questions: (a) what is the nature of depression as experienced by post-stroke patients in the acute phase? (b) what is it like to live with depression within the first weeks following stroke? Post-stroke depression occurs in at least one quarter of stroke survivors and is linked to poorer outcomes. This qualitative study is methodologically grounded in hermeneutic phenomenology, influenced by van Manen and Ricoeur. A descriptive, qualitative design was used applying in-depth interviews as the method of data collection with nine participants. The data collection took place in 2008. The material revealed two main themes that generate the feeling and description of 'living a life in shades of grey': (a) being trapped and (b) losing oneself. 'Shades of grey' could be understood as being confined in a new life-world and losing oneself as the person one knew. The participants confirmed suffering from depressive symptoms, but depression was not seen as meaningful on its own. They related their experiences of post-stroke depression in the acute phase to the losses they experienced. Nurses ought to take into account the depth of the life changes that stroke survivors may experience. There is a need for continued empirical research on how nurses may help and support stroke survivors dealing with depressive symptoms in the acute phase after stroke and how depressive symptoms develop over time. © 2011 Blackwell Publishing Ltd.

  5. Effects of species, sex, length, and locality on the mercury content of school shark Galeorhinus australis (Macleay) and gummy shark Mustelus antarcticus Guenther from south-eastern Australian waters

    Energy Technology Data Exchange (ETDEWEB)

    Walker, T.I.

    1976-12-01

    The mercury levels detected in the muscle tissues of sharks ranged from 0.01 to 2.7 ppM wet weight for school shark Galeorhinus australis (Macleay) and from 0.07 to 3.0 ppM for gummy shark Mustelus antarcticus Guenther. Estimates of the mean mercury levels for the 1971 Victorian landed commercial shark catch were found to be 0.90 ppM for the school shark and 0.37 ppM for the gummy shark. The analyses for total mercury determinations were carried out by five independent laboratories. Preliminary analyses carried out by one indicated that most of the mercury in school sharks and about two-thirds of the mercury in gummy sharks was present as methylmercury. The mercury concentrations varied exponentially with shark length. School sharks had statistically significant higher mercury levels than gummy sharks of the same length and for both the medium-sized and large individuals of each species males had significantly higher levels than females. Levels in male gummy sharks were found to be affected by locality.

  6. Temporal and Spatial Distribution of Catches of Tiger Sharks, Galeocerdo cuvier, in the Pelagic Longline Fishery Around the Hawaiian Islands

    OpenAIRE

    Polovina, Jeffrey J.; Lau, Boulderson B.

    1993-01-01

    Thirty-five tiger sharks, Galeocerdo cuvier, have been reported caught in pelagic longline gearfrom 25 to 265 n.mi. off the Hawaiian Archipelago during December 1990-May 1993. Fifteen sharks were caught farther than 50 n.mi. offshore, indicating that tiger sharks do occur well offshore and removed from benthic topography. About 89% of the sharks were caught during October-March, while only 56% of the fishing effort occurred during that period.

  7. Melancthon Grey Wind Project environmental screening report

    International Nuclear Information System (INIS)

    2005-01-01

    Canadian Hydro has proposed that the Melancthon and Grey Highlands Townships in Dufferin County, Ontario are ideally suited for the installation of a 240 MW wind farm. Assuming a turbine rating of 1.5 MW each, a total of 160 turbines could be installed. The utility has decided to undertake the project in up to 4 phases. This paper focuses on the construction and operation of a 75 MW wind turbine array (50, 1.5 MW turbines) dispersed over an area of about 3,511 hectares in the Melancthon Township. The total expected cost of the first phase is $130 million, with construction scheduled to begin in April 2005 for an in-service date of no later than March 31, 2006 to meet the Wind Power Production Incentive (WPPI) funding requirements. This environmental screening report (ESR) was completed to help Canadian Hydro fulfill regulatory requirements. It presented the project summary, the estimated capacity of the wind farm, and construction schedule. The environmental setting was also presented along with power line routing. This ESR addressed issues that may impact surface and ground water quality, air quality, soil erosion, environmental noise and disposal of waste materials. Issues affecting migratory birds, agricultural resources, community characteristics, construction related traffic, public health, historical resources and viewscapes were also addressed. The general conclusion of the ESR is that the project can be constructed, operated and decommissioned in such a manner as to minimize potentially adverse effects on the environment while enhancing the positive effects both locally and provincially. Migratory bird deaths due to collision with turbines are expected to be negligible and the effects of breeding bird habitat have been minimized through proposed mitigation measures. Environmental noise levels are expected to be within the applicable noise criteria. There will be no negative effect on property values within the viewshed of the turbines. There are many net

  8. The complete mitochondrial genome sequence of the world's largest fish, the whale shark (Rhincodon typus), and its comparison with those of related shark species.

    Science.gov (United States)

    Alam, Md Tauqeer; Petit, Robert A; Read, Timothy D; Dove, Alistair D M

    2014-04-10

    The whale shark (Rhincodon typus) is the largest extant species of fish, belonging to the order Orectolobiformes. It is listed as a "vulnerable" species on the International Union for Conservation of Nature (IUCN)'s Red List of Threatened Species, which makes it an important species for conservation efforts. We report here the first complete sequence of the mitochondrial genome (mitogenome) of the whale shark obtained by next-generation sequencing methods. The assembled mitogenome is a 16,875 bp circle, comprising of 13 protein-coding genes, two rRNA genes, 22 tRNA genes and a control region. We also performed comparative analysis of the whale shark mitogenome to the available mitogenome sequences of 17 other shark species, four from the order Orectolobiformes, five from Lamniformes and eight from Carcharhiniformes. The nucleotide composition, number and arrangement of the genes in whale shark mitogenome are the same as found in the mitogenomes of the other members of the order Orectolobiformes and its closest orders Lamniformes and Carcharhiniformes, although the whale shark mitogenome had a slightly longer control region. The availability of mitogenome sequence of whale shark will aid studies of molecular systematics, biogeography, genetic differentiation, and conservation genetics in this species. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Atmospheric Pressure Plasma Treatment for Grey Cotton Knitted Fabric

    Directory of Open Access Journals (Sweden)

    Chi-wai Kan

    2018-01-01

    Full Text Available 100% grey cotton knitted fabric contains impurities and yellowness and needs to be prepared for processing to make it suitable for coloration and finishing. Therefore, conventionally 100% grey cotton knitted fabric undergoes a process of scouring and bleaching, which involves the use of large amounts of water and chemicals, in order to remove impurities and yellowness. Due to increased environmental awareness, pursuing a reduction of water and chemicals is a current trend in textile processing. In this study, we explore the possibility of using atmospheric pressure plasma as a dry process to treat 100% grey cotton knitted fabric (single jersey and interlock before processing. Experimental results reveal that atmospheric pressure plasma treatment can effectively remove impurities from 100% grey cotton knitted fabrics and significantly improve its water absorption property. On the other hand, if 100% grey cotton knitted fabrics are pretreated with plasma and then undergo a normal scouring process, the treatment time is reduced. In addition, the surface morphological and chemical changes in plasma-treated fabrics were studied and compared with the conventionally treated fabrics using scanning electron microscope (SEM, Fourier-transform infrared spectroscopy-attenuated total reflection (FTIR-ATR and X-ray photoelectron spectroscopy (XPS. The decrease in carbon content, as shown in XPS, reveal the removal of surface impurities. The oxygen-to-carbon (O/C ratios of the plasma treated knitted fabrics reveal enhanced hydrophilicity.

  10. Ultraviolet (UV) disinfection of grey water: particle size effects.

    Science.gov (United States)

    Winward, G P; Avery, L M; Stephenson, T; Jefferson, B

    2008-02-01

    The impact of water quality on the ultraviolet (UV) disinfection of grey water was investigated with reference to urban water reuse. Direct UV disinfection of grey water did not meet the stringent California State Title 22 criteria for unrestricted urban water reuse due to the presence of particulate material ranging from or = 2000 microm in size. Grey water was manipulated by settling to produce fractions of varying particle size distributions and blending was employed post-disinfection to extract particle-associated coliforms (PACs). The efficacy of UV disinfection was found to be linked to the particle size of the grey water fractions. The larger particle size fractions with a mean particle size of 262 microm and above were observed to shield more coliforms from UV light than did the smaller particles with a mean particle size below 119 microm. Up to 70% of total coliforms in the larger particle size fractions were particle-associated following a UV dose (fluence) of 260 mJ.cm(-2) and would remain undetected by standard coliform enumeration techniques. Implications for urban water reuse are discussed and recommendations made for grey water treatment to ensure removal of particle-associated indicator bacteria and pathogens prior to UV disinfection.

  11. Determining Correlation between Shark Location and Atmospheric Wind and Thermal Parameters.

    Science.gov (United States)

    Merchant, J.

    2017-12-01

    Millions of people visit the nation's shorelines every summer. As recreational use of the ocean increases across the country, so too does the risk of shark attacks on people. According to George H. Burgess, curator for the International Shark Attack File and the Florida Program for Shark Research "The number of shark-human interactions occurring in a given year is directly correlated with the amount of time humans spend in the sea. As world population continues its upsurge and interest in aquatic recreation concurrently rises, we realistically should expect increases in the number of shark attacks and other aquatic recreation-related injuries". Burgess' analysis released in February of 2016, states "2015 yearly total of 98 unprovoked attacks (worldwide) was the highest on record" until 2016. Adding to the previous record number of global shark/human interactions in 2015 were 10 confirmed cases of people bitten by sharks off the shores of North Carolina and South Carolina over a five week period in June and July of 2015. The unusually high amount of attacks within close proximity over a short period of time garnered significant media attention nationwide. Preliminary data resulting from the analysis of these 2015 shark attacks and separate acoustic shark location data from Dr. Gregory Skomal's (Program Manager, Senior Marine Fisheries Biologist for the state of Massachusetts) ongoing research across Cape Code do indicate a correlation between environmental and biological factors leading up to human/shark interactions. Not only will these preliminary findings be presented, but a full description of how the use of higher resolution remote sensing and in-situ surface wind and thermal measurements would improve real time detection and prediction of these dangerous conditions, up to hours in advance, mitigating human risk and interaction with shark.

  12. Reef-fidelity and migration of tiger sharks, Galeocerdo cuvier, across the coral sea

    KAUST Repository

    Werry, Jonathan M.

    2014-01-08

    Knowledge of the habitat use and migration patterns of large sharks is important for assessing the effectiveness of large predator Marine Protected Areas (MPAs), vulnerability to fisheries and environmental influences, and management of shark-human interactions. Here we compare movement, reef-fidelity, and ocean migration for tiger sharks, Galeocerdo cuvier, across the Coral Sea, with an emphasis on New Caledonia. Thirty-three tiger sharks (1.54 to 3.9 m total length) were tagged with passive acoustic transmitters and their localised movements monitored on receiver arrays in New Caledonia, the Chesterfield and Lord Howe Islands in the Coral Sea, and the east coast of Queensland, Australia. Satellite tags were also used to determine habitat use and movements among habitats across the Coral Sea. Sub-adults and one male adult tiger shark displayed year-round residency in the Chesterfields with two females tagged in the Chesterfields and detected on the Great Barrier Reef, Australia, after 591 and 842 days respectively. In coastal barrier reefs, tiger sharks were transient at acoustic arrays and each individual demonstrated a unique pattern of occurrence. From 2009 to 2013, fourteen sharks with satellite and acoustic tags undertook wide-ranging movements up to 1114 km across the Coral Sea with eight detected back on acoustic arrays up to 405 days after being tagged. Tiger sharks dove 1136 m and utilised three-dimensional activity spaces averaged at 2360 km3. The Chesterfield Islands appear to be important habitat for sub-adults and adult male tiger sharks. Management strategies need to consider the wide-ranging movements of large (sub-adult and adult) male and female tiger sharks at the individual level, whereas fidelity to specific coastal reefs may be consistent across groups of individuals. Coastal barrier reef MPAs, however, only afford brief protection for large tiger sharks, therefore determining the importance of other oceanic Coral Sea reefs should be a

  13. Reef-fidelity and migration of tiger sharks, Galeocerdo cuvier, across the coral sea

    KAUST Repository

    Werry, Jonathan M.; Planes, Serge; Berumen, Michael L.; Lee, Kate A.; Braun, Camrin D.; Clua, Eric

    2014-01-01

    Knowledge of the habitat use and migration patterns of large sharks is important for assessing the effectiveness of large predator Marine Protected Areas (MPAs), vulnerability to fisheries and environmental influences, and management of shark-human interactions. Here we compare movement, reef-fidelity, and ocean migration for tiger sharks, Galeocerdo cuvier, across the Coral Sea, with an emphasis on New Caledonia. Thirty-three tiger sharks (1.54 to 3.9 m total length) were tagged with passive acoustic transmitters and their localised movements monitored on receiver arrays in New Caledonia, the Chesterfield and Lord Howe Islands in the Coral Sea, and the east coast of Queensland, Australia. Satellite tags were also used to determine habitat use and movements among habitats across the Coral Sea. Sub-adults and one male adult tiger shark displayed year-round residency in the Chesterfields with two females tagged in the Chesterfields and detected on the Great Barrier Reef, Australia, after 591 and 842 days respectively. In coastal barrier reefs, tiger sharks were transient at acoustic arrays and each individual demonstrated a unique pattern of occurrence. From 2009 to 2013, fourteen sharks with satellite and acoustic tags undertook wide-ranging movements up to 1114 km across the Coral Sea with eight detected back on acoustic arrays up to 405 days after being tagged. Tiger sharks dove 1136 m and utilised three-dimensional activity spaces averaged at 2360 km3. The Chesterfield Islands appear to be important habitat for sub-adults and adult male tiger sharks. Management strategies need to consider the wide-ranging movements of large (sub-adult and adult) male and female tiger sharks at the individual level, whereas fidelity to specific coastal reefs may be consistent across groups of individuals. Coastal barrier reef MPAs, however, only afford brief protection for large tiger sharks, therefore determining the importance of other oceanic Coral Sea reefs should be a

  14. Was everything bigger in Texas? Characterization and trends of a land-based recreational shark fishery

    Science.gov (United States)

    Ajemian, Matthew J.; Jose, Philip D.; Froeschke, John T.; Wildhaber, Mark L.; Stunz, Gregory W.

    2016-01-01

    Although current assessments of shark population trends involve both fishery-independent and fishery-dependent data, the latter are generally limited to commercial landings that may neglect nearshore coastal habitats. Texas has supported the longest organized land-based recreational shark fishery in the United States, yet no studies have used this “non-traditional” data source to characterize the catch composition or trends in this multidecadal fishery. We analyzed catch records from two distinct periods straddling heavy commercial exploitation of sharks in the Gulf of Mexico (historical period = 1973–1986; modern period = 2008–2015) to highlight and make available the current status and historical trends in Texas’ land-based shark fishery. Catch records describing large coastal species (>1,800 mm stretched total length [STL]) were examined using multivariate techniques to assess catch seasonality and potential temporal shifts in species composition. These fishery-dependent data revealed consistent seasonality that was independent of the data set examined, although distinct shark assemblages were evident between the two periods. Similarity percentage analysis suggested decreased contributions of Lemon Shark Negaprion brevirostris over time and a general shift toward the dominance of Bull Shark Carcharhinus leucas and Blacktip Shark C. limbatus. Comparisons of mean STL for species captured in historical and modern periods further identified significant decreases for both Bull Sharks and Lemon Sharks. Size structure analysis showed a distinct paucity of landed individuals over 2,000 mm STL in recent years. Although inherent biases in reporting and potential gear-related inconsistencies undoubtedly influenced this fishery-dependent data set, the patterns in our findings documented potential declines in the size and occurrence of select large coastal shark species off Texas, consistent with declines reported in the Gulf of Mexico. Future management efforts

  15. Impacts of food web structure and feeding behavior on mercury exposure in Greenland Sharks (Somniosus microcephalus).

    Science.gov (United States)

    McMeans, Bailey C; Arts, Michael T; Fisk, Aaron T

    2015-03-15

    Benthic and pelagic food web components in Cumberland Sound, Canada were explored as sources of total mercury (THg) to Greenland Sharks (Somniosus microcephalus) via both bottom-up food web transfer and top-down shark feeding behavior. Log10THg increased significantly with δ(15)N and trophic position from invertebrates (0.01 ± 0.01 μg · g(-1) [113 ± 1 ng · g(-1)] dw in copepods) to Greenland Sharks (3.54 ± 1.02 μg · g(-1)). The slope of the log10THg vs. δ(15)N linear regression was higher for pelagic compared to benthic food web components (excluding Greenland Sharks, which could not be assigned to either food web), which resulted from THg concentrations being higher at the base of the benthic food web (i.e., in benthic than pelagic primary consumers). However, feeding habitat is unlikely to consistently influence shark THg exposure in Cumberland Sound because THg concentrations did not consistently differ between benthic and pelagic shark prey. Further, size, gender and feeding behavior (inferred from stable isotopes and fatty acids) were unable to significantly explain THg variability among individual Greenland Sharks. Possible reasons for this result include: 1) individual sharks feeding as generalists, 2) high overlap in THg among shark prey, and 3) differences in turnover time between ecological tracers and THg. This first assessment of Greenland Shark THg within an Arctic food web revealed high concentrations consistent with biomagnification, but low ability to explain intra-specific THg variability. Our findings of high THg levels and consumption of multiple prey types, however, suggest that Greenland Sharks acquire THg through a variety of trophic pathways and are a significant contributor to the total biotic THg pool in northern seas. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Reef-fidelity and migration of tiger sharks, Galeocerdo cuvier, across the Coral Sea.

    Science.gov (United States)

    Werry, Jonathan M; Planes, Serge; Berumen, Michael L; Lee, Kate A; Braun, Camrin D; Clua, Eric

    2014-01-01

    Knowledge of the habitat use and migration patterns of large sharks is important for assessing the effectiveness of large predator Marine Protected Areas (MPAs), vulnerability to fisheries and environmental influences, and management of shark-human interactions. Here we compare movement, reef-fidelity, and ocean migration for tiger sharks, Galeocerdo cuvier, across the Coral Sea, with an emphasis on New Caledonia. Thirty-three tiger sharks (1.54 to 3.9 m total length) were tagged with passive acoustic transmitters and their localised movements monitored on receiver arrays in New Caledonia, the Chesterfield and Lord Howe Islands in the Coral Sea, and the east coast of Queensland, Australia. Satellite tags were also used to determine habitat use and movements among habitats across the Coral Sea. Sub-adults and one male adult tiger shark displayed year-round residency in the Chesterfields with two females tagged in the Chesterfields and detected on the Great Barrier Reef, Australia, after 591 and 842 days respectively. In coastal barrier reefs, tiger sharks were transient at acoustic arrays and each individual demonstrated a unique pattern of occurrence. From 2009 to 2013, fourteen sharks with satellite and acoustic tags undertook wide-ranging movements up to 1114 km across the Coral Sea with eight detected back on acoustic arrays up to 405 days after being tagged. Tiger sharks dove 1136 m and utilised three-dimensional activity spaces averaged at 2360 km³. The Chesterfield Islands appear to be important habitat for sub-adults and adult male tiger sharks. Management strategies need to consider the wide-ranging movements of large (sub-adult and adult) male and female tiger sharks at the individual level, whereas fidelity to specific coastal reefs may be consistent across groups of individuals. Coastal barrier reef MPAs, however, only afford brief protection for large tiger sharks, therefore determining the importance of other oceanic Coral Sea reefs should be a

  17. The Shark Random Swim - (Lévy Flight with Memory)

    Science.gov (United States)

    Businger, Silvia

    2018-05-01

    The Elephant Random Walk (ERW), first introduced by Schütz and Trimper (Phys Rev E 70:045101, 2004), is a one-dimensional simple random walk on Z having a memory about the whole past. We study the Shark Random Swim, a random walk with memory about the whole past, whose steps are α -stable distributed with α \\in (0,2] . Our aim in this work is to study the impact of the heavy tailed step distributions on the asymptotic behavior of the random walk. We shall see that, as for the ERW, the asymptotic behavior of the Shark Random Swim depends on its memory parameter p, and that a phase transition can be observed at the critical value p=1/α.

  18. Spatial ecology of blue shark and shortfin mako in southern Peru: local abundance, habitat preferences and implications for conservation

    DEFF Research Database (Denmark)

    Adams, Grant D.; Flores, Daniel; Flores, Oscar Galindo

    2016-01-01

    While global declines of pelagic shark populations have been recognized for several years, conservation efforts remain hampered by a poor understanding of the spatial distribution and ecology. Two species of conservation concern are the blue shark Prionace glauca and the shortfin mako shark Isuru...

  19. 78 FR 36149 - Magnuson-Stevens Act Provisions; Implementation of the Shark Conservation Act of 2010; Correction

    Science.gov (United States)

    2013-06-17

    .... 111014628-3329-01] RIN 0648-BB54 Magnuson-Stevens Act Provisions; Implementation of the Shark Conservation.... SUMMARY: NMFS published a proposed rule on May 2, 2013, to implement provisions of the Shark Conservation Act of 2010 (SCA) that prohibit any person from removing any of the fins of a shark at sea, possessing...

  20. 77 FR 39648 - Atlantic Highly Migratory Species; Commercial Gulf of Mexico Non-Sandbar Large Coastal Shark Fishery

    Science.gov (United States)

    2012-07-05

    ... Large Coastal Shark Fishery AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and... commercial fishery for non-sandbar large coastal sharks (LCS) in the Gulf of Mexico region. This action is.... SUPPLEMENTARY INFORMATION: The Atlantic shark fisheries are managed under the 2006 Consolidated Atlantic Highly...

  1. 78 FR 40687 - Magnuson-Stevens Act Provisions; Implementation of the Shark Conservation Act of 2010; Extension...

    Science.gov (United States)

    2013-07-08

    .... 111014628-3329-01] RIN 0648-BB54 Magnuson-Stevens Act Provisions; Implementation of the Shark Conservation... period. SUMMARY: NMFS published a proposed rule on May 2, 2013, to implement provisions of the Shark Conservation Act of 2010 (SCA) that prohibit any person from removing any of the fins of a shark at sea...

  2. 76 FR 61092 - Stock Assessment Reports for Dusky, Sandbar, and Blacknose Sharks in the U.S. Atlantic and Gulf...

    Science.gov (United States)

    2011-10-03

    ... Assessment Reports for Dusky, Sandbar, and Blacknose Sharks in the U.S. Atlantic and Gulf of Mexico AGENCY... reports for dusky, sandbar, and blacknose sharks in the Atlantic and Gulf of Mexico. The reports summarize... sharks should be sent to Peter Cooper, Highly Migratory Species Management Division (F/SF1), National...

  3. 76 FR 53840 - Fisheries of the Exclusive Economic Zone Off Alaska; Other Rockfish, Other Flatfish, Sharks, and...

    Science.gov (United States)

    2011-08-30

    ... Flatfish, Sharks, and Skates in the Bering Sea and Aleutian Islands Management Area AGENCY: National Marine...-specified reserve to the initial total allowable catch of other rockfish, other flatfish, sharks, and skates..., BSAI other flatfish, BSAI sharks, and BSAI skates was established as 425 metric tons (mt), 2,550 mt, 43...

  4. 76 FR 59924 - Fisheries of the Exclusive Economic Zone Off Alaska; Sharks in the Bering Sea and Aleutian...

    Science.gov (United States)

    2011-09-28

    .... 101126521-0640-2] RIN 0648-XA733 Fisheries of the Exclusive Economic Zone Off Alaska; Sharks in the Bering... prohibiting retention of sharks in the Bering Sea and Aleutian Islands management area (BSAI). This action is necessary because the 2011 total allowable catch (TAC) of sharks in the BSAI has been reached. DATES...

  5. 78 FR 57097 - Fisheries of the Exclusive Economic Zone Off Alaska; Sharks in the Bering Sea and Aleutian...

    Science.gov (United States)

    2013-09-17

    .... 121018563-3418-02] RIN 0648-XC872 Fisheries of the Exclusive Economic Zone Off Alaska; Sharks in the Bering... prohibiting retention of sharks in the Bering Sea and Aleutian Islands management area (BSAI). This action is necessary because the 2013 total allowable catch (TAC) of sharks in the BSAI has been reached. DATES...

  6. DNA capture reveals transoceanic gene flow in endangered river sharks

    OpenAIRE

    Li, Chenhong; Corrigan, Shannon; Yang, Lei; Straube, Nicolas; Harris, Mark; Hofreiter, Michael; White, William T.; Naylor, Gavin J. P.

    2015-01-01

    The river sharks of the genus Glyphis, widely feared as man-eaters throughout India, remain very poorly known to science. The group constitutes five described species, all of which are considered highly endangered and restricted to freshwater systems in Australasia and Southeast Asia. DNA sequence data derived from 19th-century dried museum material augmented with contemporary samples indicates that only three of the five currently described species are valid; that there is a genetically dist...

  7. Algae Reefs in Shark Bay, Western Australia, Australia

    Science.gov (United States)

    1990-01-01

    Numerous algae reefs are seen in Shark Bay, Western Australia, Australia (26.0S, 113.5E) especially in the southern portions of the bay. The south end is more saline because tidal flow in and out of the bay is restricted by sediment deposited at the north and central end of the bay opposite the mouth of the Wooramel River. This extremely arid region produces little sediment runoff so that the waters are very clear, saline and rich in algae.

  8. Functional morphology of the radialis muscle in shark tails.

    Science.gov (United States)

    Flammang, Brooke E

    2010-03-01

    The functional morphology of intrinsic caudal musculature in sharks has not been studied previously, though the kinematics and function of body musculature have been the focus of a great deal of research. In the tail, ventral to the axial myomeres, there is a thin strip of red muscle with fibers angled dorsoposteriorly, known as the radialis. This research gives the first anatomical description of the radialis muscle in sharks, and addresses the hypothesis that the radialis muscle provides postural stiffening in the tail of live swimming sharks. The radialis muscle fibers insert onto the deepest layers of the stratum compactum, the more superior layers of which are orthogonally arrayed and connect to the epidermis. The two deepest layers of the stratum compactum insert onto the proximal ends of the ceratotrichia of the caudal fin. This anatomical arrangement exists in sharks and is modified in rays, but was not found in skates or chimaeras. Electromyography of the caudal muscles of dogfish swimming steadily at 0.25 and 0.5 body lengths per second (Ls(-1)) exhibited a pattern of anterior to posterior activation of the radialis muscle, followed by activation of red axial muscle in the more anteriorly located ipsilateral myomeres of the caudal peduncle; at 0.75 L s(-1), only the anterior portion of the radialis and white axial muscle of the contralateral peduncular myomeres were active. Activity of the radialis muscle occurred during periods of the greatest drag incurred by the tail during the tail beat and preceded the activity of more anteriorly located axial myomeres. This nonconformity to the typical anterior to posterior wave of muscle activation in fish swimming, in combination with anatomical positioning of the radialis muscles and stratum compactum, suggests that radialis activity may have a postural function to stiffen the fin, and does not function as a typical myotomal muscle.

  9. The V-SHARK high contrast imager at LBT

    Science.gov (United States)

    Pedichini, F.; Ambrosino, F.; Centrone, M.; Farinato, J.; Li Causi, G.; Pinna, E.; Puglisi, A.; Stangalini, M.; Testa, V.

    2016-08-01

    In the framework of the SHARK project the visible channel is a novel instrument synergic to the NIR channel and exploiting the performances of the LBT XAO at visible wavelengths. The status of the project is presented together with the design study of this innovative instrument optimized for high contrast imaging by means of high frame rate. Its expected results will be presented comparing the simulations with the real data of the "Forerunner" experiment taken at 630nm.

  10. Convergent evolution in mechanical design of lamnid sharks and tunas.

    Science.gov (United States)

    Donley, Jeanine M; Sepulveda, Chugey A; Konstantinidis, Peter; Gemballa, Sven; Shadwick, Robert E

    2004-05-06

    The evolution of 'thunniform' body shapes in several different groups of vertebrates, including whales, ichthyosaurs and several species of large pelagic fishes supports the view that physical and hydromechanical demands provided important selection pressures to optimize body design for locomotion during vertebrate evolution. Recognition of morphological similarities between lamnid sharks (the most well known being the great white and the mako) and tunas has led to a general expectation that they also have converged in their functional design; however, no quantitative data exist on the mechanical performance of the locomotor system in lamnid sharks. Here we examine the swimming kinematics, in vivo muscle dynamics and functional morphology of the force-transmission system in a lamnid shark, and show that the evolutionary convergence in body shape and mechanical design between the distantly related lamnids and tunas is much more than skin deep; it extends to the depths of the myotendinous architecture and the mechanical basis for propulsive movements. We demonstrate that not only have lamnids and tunas converged to a much greater extent than previously known, but they have also developed morphological and functional adaptations in their locomotor systems that are unlike virtually all other fishes.

  11. Ecological drivers of shark distributions along a tropical coastline.

    Directory of Open Access Journals (Sweden)

    Peter M Yates

    Full Text Available As coastal species experience increasing anthropogenic pressures there is a growing need to characterise the ecological drivers of their abundance and habitat use, and understand how they may respond to changes in their environment. Accordingly, fishery-independent surveys were undertaken to investigate shark abundance along approximately 400 km of the tropical east coast of Australia. Generalised linear models were used to identify ecological drivers of the abundance of immature blacktip Carcharhinus tilstoni/Carcharhinus limbatus, pigeye Carcharhinus amboinensis, and scalloped hammerhead Sphyrna lewini sharks. Results indicated general and species-specific patterns in abundance that were characterised by a range of abiotic and biotic variables. Relationships with turbidity and salinity were similar across multiple species, highlighting the importance of these variables in the functioning of communal shark nurseries. In particular, turbid environments were especially important for all species at typical oceanic salinities. Mangrove proximity, depth, and water temperature were also important; however, their influence varied between species. Ecological drivers may promote spatial diversity in habitat use along environmentally heterogeneous coastlines and may therefore have important implications for population resilience.

  12. Ecological drivers of shark distributions along a tropical coastline.

    Science.gov (United States)

    Yates, Peter M; Heupel, Michelle R; Tobin, Andrew J; Simpfendorfer, Colin A

    2015-01-01

    As coastal species experience increasing anthropogenic pressures there is a growing need to characterise the ecological drivers of their abundance and habitat use, and understand how they may respond to changes in their environment. Accordingly, fishery-independent surveys were undertaken to investigate shark abundance along approximately 400 km of the tropical east coast of Australia. Generalised linear models were used to identify ecological drivers of the abundance of immature blacktip Carcharhinus tilstoni/Carcharhinus limbatus, pigeye Carcharhinus amboinensis, and scalloped hammerhead Sphyrna lewini sharks. Results indicated general and species-specific patterns in abundance that were characterised by a range of abiotic and biotic variables. Relationships with turbidity and salinity were similar across multiple species, highlighting the importance of these variables in the functioning of communal shark nurseries. In particular, turbid environments were especially important for all species at typical oceanic salinities. Mangrove proximity, depth, and water temperature were also important; however, their influence varied between species. Ecological drivers may promote spatial diversity in habitat use along environmentally heterogeneous coastlines and may therefore have important implications for population resilience.

  13. Impacts of Triclosan in Grey water on Soil Microorganisms

    International Nuclear Information System (INIS)

    Harrow, D.I; Felker, J.M; Baker, K.H

    2011-01-01

    The use of grey water for irrigation is becoming a common practice in arid regions such as the Southwestern US, the Middle East, Australia, and China. While grey water supplies nutrients to soil ecosystems, the possible impact of trace contaminants, particularly pharmaceuticals and personal care products, has not been determined. This paper examined the impact of triclosan, an antibacterial agent commonly added to consumer products, on microbial populations and microbial diversity in soil irrigated with grey water. While there was no change in the total number of heterotrophic microorganisms in the soil, both the types and the antibiotic resistance of the microorganisms were significantly influenced by triclosan. The proportion of the microbial isolates resistant to antibiotics increased while at the same time, overall diversity of the microbial community decreased.

  14. Green Walls as an Approach in Grey Water Treatment

    Science.gov (United States)

    Rysulova, Martina; Kaposztasova, Daniela; Vranayova, Zuzana

    2017-10-01

    Grey water contributes significantly to waste water parameters such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total phosphorus (Ptotal), total nitrogen (Ntotal), ammonium, boron, metals, salts, surfactants, synthetic chemicals, oils and greases, xenobiotic substances and microorganisms. Concentration of these pollutants and the water quality highlights the importance of treatment process in grey water systems. Treatment technologies operating under low energy and maintenance are usually preferred, since they are more cost effective for users. Treatment technologies based on natural processes represent an example of such technology including vegetated wall. Main aim of this paper is to introduce the proposal of vegetated wall managing grey water and brief characteristic of proposed system. Is expected that prepared experiment will establish the purifying ability and the potential of green wall application as an efficient treatment technology.

  15. Internet trade and threat of the grey area

    Directory of Open Access Journals (Sweden)

    Anna Ćwiąkała-Małys

    2012-06-01

    Full Text Available In recent years it has been of great interest to tax, fiscal and customs authorities how trade and services provided over the Internet develop. A long time ago it was stated that the intense development of the Internet contributes to the expansion of the grey area. The grey area’s functioning is very unfavourable to the state economy, because although it creates GDP, it does not directly support the state budget. When considering reduced inflows to the state budget and increases in the deficit, it is reasonable to take any and all actions in order to limit the grey area in each field of social and economic life. Thus, the interest of specialized public authorities in this field should not raise any concerns.

  16. Converter of a continuous code into the Grey code

    International Nuclear Information System (INIS)

    Gonchar, A.I.; TrUbnikov, V.R.

    1979-01-01

    Described is a converter of a continuous code into the Grey code used in a 12-charged precision amplitude-to-digital converter to decrease the digital component of spectrometer differential nonlinearity to +0.7% in the 98% range of the measured band. To construct the converter of a continuous code corresponding to the input signal amplitude into the Grey code used is the regularity in recycling of units and zeroes in each discharge of the Grey code in the case of a continuous change of the number of pulses of a continuous code. The converter is constructed on the elements of 155 series, the frequency of continuous code pulse passing at the converter input is 25 MHz

  17. Environmental vulnerability assessment using Grey Analytic Hierarchy Process based model

    International Nuclear Information System (INIS)

    Sahoo, Satiprasad; Dhar, Anirban; Kar, Amlanjyoti

    2016-01-01

    Environmental management of an area describes a policy for its systematic and sustainable environmental protection. In the present study, regional environmental vulnerability assessment in Hirakud command area of Odisha, India is envisaged based on Grey Analytic Hierarchy Process method (Grey–AHP) using integrated remote sensing (RS) and geographic information system (GIS) techniques. Grey–AHP combines the advantages of classical analytic hierarchy process (AHP) and grey clustering method for accurate estimation of weight coefficients. It is a new method for environmental vulnerability assessment. Environmental vulnerability index (EVI) uses natural, environmental and human impact related factors, e.g., soil, geology, elevation, slope, rainfall, temperature, wind speed, normalized difference vegetation index, drainage density, crop intensity, agricultural DRASTIC value, population density and road density. EVI map has been classified into four environmental vulnerability zones (EVZs) namely: ‘low’, ‘moderate’ ‘high’, and ‘extreme’ encompassing 17.87%, 44.44%, 27.81% and 9.88% of the study area, respectively. EVI map indicates that the northern part of the study area is more vulnerable from an environmental point of view. EVI map shows close correlation with elevation. Effectiveness of the zone classification is evaluated by using grey clustering method. General effectiveness is in between “better” and “common classes”. This analysis demonstrates the potential applicability of the methodology. - Highlights: • Environmental vulnerability zone identification based on Grey Analytic Hierarchy Process (AHP) • The effectiveness evaluation by means of a grey clustering method with support from AHP • Use of grey approach eliminates the excessive dependency on the experience of experts.

  18. Environmental vulnerability assessment using Grey Analytic Hierarchy Process based model

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, Satiprasad [School of Water Resources, Indian Institute of Technology Kharagpur (India); Dhar, Anirban, E-mail: anirban.dhar@gmail.com [Department of Civil Engineering, Indian Institute of Technology Kharagpur (India); Kar, Amlanjyoti [Central Ground Water Board, Bhujal Bhawan, Faridabad, Haryana (India)

    2016-01-15

    Environmental management of an area describes a policy for its systematic and sustainable environmental protection. In the present study, regional environmental vulnerability assessment in Hirakud command area of Odisha, India is envisaged based on Grey Analytic Hierarchy Process method (Grey–AHP) using integrated remote sensing (RS) and geographic information system (GIS) techniques. Grey–AHP combines the advantages of classical analytic hierarchy process (AHP) and grey clustering method for accurate estimation of weight coefficients. It is a new method for environmental vulnerability assessment. Environmental vulnerability index (EVI) uses natural, environmental and human impact related factors, e.g., soil, geology, elevation, slope, rainfall, temperature, wind speed, normalized difference vegetation index, drainage density, crop intensity, agricultural DRASTIC value, population density and road density. EVI map has been classified into four environmental vulnerability zones (EVZs) namely: ‘low’, ‘moderate’ ‘high’, and ‘extreme’ encompassing 17.87%, 44.44%, 27.81% and 9.88% of the study area, respectively. EVI map indicates that the northern part of the study area is more vulnerable from an environmental point of view. EVI map shows close correlation with elevation. Effectiveness of the zone classification is evaluated by using grey clustering method. General effectiveness is in between “better” and “common classes”. This analysis demonstrates the potential applicability of the methodology. - Highlights: • Environmental vulnerability zone identification based on Grey Analytic Hierarchy Process (AHP) • The effectiveness evaluation by means of a grey clustering method with support from AHP • Use of grey approach eliminates the excessive dependency on the experience of experts.

  19. The immunomodulatory effects of shark cartilage on the mouse and human immune system

    Directory of Open Access Journals (Sweden)

    ali Sheikhian

    2007-01-01

    Materials and methods: In an experimental study, the effects of different doses of shark cartilage on humoral (antibody titer immune response against sheep red blood cells (SRBC, were measured in mouse. In addition, we evaluated the modulatory effects of the shark cartilage on the natural killer (NK activity of the peritoneal cells of mouse against a tumor cell line called K562, according to the standard methods. The proliferative response of the human peripheral blood mononuclear cells was measured under the influence of shark cartilage. Results: Pure shark cartilage enhanced antibody response against SRBC in vivo. The hemagglutination titer which was 1/147 in the control group (injected with hen cartilage, increased to 1/1355 in the test group. The optimal dose was 100 mg/ml. both type of cartilage had blastogenic effect on peripheral blood mononuclear cells (the blastogenic index was 6.7 and 4.9 for impure shark cartilage and hen cartilage, respectively. NK activity was inhibited completely by pure shark cartilage (the amount of the killing activity of the effector peritoneal cells for the control and test groups against target cells was 25.9% and 5.5% respectively. Conclusion: Shark cartilage has a potent immunomodulatory effect on the specific immune mechanisms and some inhibitory effects on the innate immune mechanisms such as NC activity. Since the specific immunity has a more pivotal role against tumor formation, shark cartilage can be used as a cancer immunotherapeutic.

  20. Whale sharks target dense prey patches of sergestid shrimp off Tanzania

    KAUST Repository

    Rohner, C. A.; Armstrong, A. J.; Pierce, S. J.; Prebble, C. E. M.; Cagua, E. F.; Cochran, J. E. M.; Berumen, Michael L.; Richardson, A. J.

    2015-01-01

    Large planktivores require high-density prey patches to make feeding energetically viable. This is a major challenge for species living in tropical and subtropical seas, such as whale sharks Rhincodon typus. Here, we characterize zooplankton biomass, size structure and taxonomic composition from whale shark feeding events and background samples at Mafia Island, Tanzania. The majority of whale sharks were feeding (73%, 380 of 524 observations), with the most common behaviour being active surface feeding (87%). We used 20 samples collected from immediately adjacent to feeding sharks and an additional 202 background samples for comparison to show that plankton biomass was ∼10 times higher in patches where whale sharks were feeding (25 vs. 2.6 mg m-3). Taxonomic analyses of samples showed that the large sergestid Lucifer hanseni (∼10 mm) dominated while sharks were feeding, accounting for ∼50% of identified items, while copepods (<2 mm) dominated background samples. The size structure was skewed towards larger animals representative of L.hanseni in feeding samples. Thus, whale sharks at Mafia Island target patches of dense, large, zooplankton dominated by sergestids. Large planktivores, such as whale sharks, which generally inhabit warm oligotrophic waters, aggregate in areas where they can feed on dense prey to obtain sufficient energy. © 2015 © The Author 2015. Published by Oxford University Press. All rights reserved.

  1. 77 FR 75896 - Atlantic Highly Migratory Species; 2013 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2012-12-26

    ... the non-sandbar large coastal shark quotas and retention limits in 2013 and asked for the reasoning... geographical distribution of non-sandbar large coastal shark landings in the Atlantic throughout the season... the 2006 Consolidated HMS FMP on EFH, we reviewed the geographical range of all HMS and analyzed the...

  2. 78 FR 70500 - Atlantic Highly Migratory Species; 2014 Atlantic Shark Commercial Fishing Seasons

    Science.gov (United States)

    2013-11-26

    ...- tourism when proposing shark fishing season opening dates. While shark aggregations may benefit eco-tourism, this factor is not one of the specific criteria NMFS uses to establish opening dates. Rather... the religious holiday of Lent and a closure for the fishery on July 1 before the State of Louisiana re...

  3. A first description of the artisanal shark fishery in northern Madagascar

    African Journals Online (AJOL)

    In the past two decades, small, targeted artisanal shark fisheries have developed in the extreme north of Madagascar, largely in response to the shark fin trade. Few studies have been undertaken to assess the biological characteristics and impact of these fisheries. Here, we developed a profile of the fishery in the region of ...

  4. Sharks caught in the protective gill nets off KwaZulu-Natal, South ...

    African Journals Online (AJOL)

    Between 1980 and 2001, a total of 661 African angel sharks Squatina africana was caught in the protective nets off KwaZulu-Natal, South Africa. The mean annual catch was 30 sharks (range = 11–69, SD = 12.4), with no trend in catch rate over the study period. Individuals were caught throughout the year and through ...

  5. Sharks caught in the protective gill nets off KwaZulu-Natal, South ...

    African Journals Online (AJOL)

    Between 1978 and 1998, a total of 3 385 scalloped hammerhead sharks Sphyrna lewini was caught in the protective nets off KwaZulu-Natal. The mean annual catch was 166 sharks (range 60–279). There was a significant decrease in catch rate with time, but the relationship with the population size in KwaZulu-Natal waters ...

  6. Seasonal variability of bull and tiger shark presence on the west ...

    African Journals Online (AJOL)

    A fisheries-independent survey using longlines and drumlines, and an acoustic telemetry study, revealed that bull sharks Carcharhinus leucas and tiger sharks Galeocerdo cuvier occur throughout the year off the west coast of Reunion Island. The research, which commenced in 2011, was conducted in response to an ...

  7. Ecological impact of the end-Cretaceous extinction on lamniform sharks.

    Directory of Open Access Journals (Sweden)

    Rachel A Belben

    Full Text Available Lamniform sharks are apex marine predators undergoing dramatic local and regional decline worldwide, with consequences for marine ecosystems that are difficult to predict. Through their long history, lamniform sharks have faced widespread extinction, and understanding those 'natural experiments' may help constrain predictions, placing the current crisis in evolutionary context. Here we show, using novel morphometric analyses of fossil shark teeth, that the end-Cretaceous extinction of many sharks had major ecological consequences. Post-extinction ecosystems supported lower diversity and disparity of lamniforms, and were dominated by significantly smaller sharks with slimmer, smoother and less robust teeth. Tooth shape is intimately associated with ecology, feeding and prey type, and by integrating data from extant sharks we show that latest Cretaceous sharks occupied similar niches to modern lamniforms, implying similar ecosystem structure and function. By comparison, species in the depauperate post-extinction community occupied niches most similar to those of juvenile sand tigers (Carcharias taurus. Our data show that quantitative tooth morphometrics can distinguish lamniform sharks due to dietary differences, providing critical insights into ecological consequences of past extinction episodes.

  8. The energetic, physiological, and behavioral response of lemon sharks (Negaprion brevirostris) to simulated longline capture.

    Science.gov (United States)

    Bouyoucos, Ian A; Suski, Cory D; Mandelman, John W; Brooks, Edward J

    2017-05-01

    Commercial fisheries bycatch is a considerable threat to elasmobranch population recovery, and techniques to mitigate sub-lethal consequences can be improved with data on the energetic, physiological, and behavioral response of individuals to capture. This study sought to estimate the effects of simulated longline capture on the behavior, energy use, and physiological stress of juvenile lemon sharks (Negaprion brevirostris). Captive sharks equipped with acceleration biologgers were subjected to 1h of simulated longline capture. Swimming behaviors were identified from acceleration data using a machine-learning algorithm, energetic costs were estimated using accelerometer-calibrated relationships and respirometry, and physiological stress was quantified with point-of-care blood analyzers. During capture, sharks exhibited nine-fold increases in the frequency of burst swimming, 98% reductions in resting, and swam as often as unrestrained sharks. Aerobic metabolic rates during capture were 8% higher than for unrestrained sharks, and accounted for a 57.7% increase in activity costs when excess post-exercise oxygen consumption was included. Lastly, sharks exhibited significant increases in blood lactate and glucose, but no change in blood pH after 1h of capture. Therefore, these results provide preliminary insight into the behavioral and energetic responses of sharks to capture, and have implications for mitigating sub-lethal consequences of capture for sharks as commercial longline bycatch. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. First visual record of a living basking shark Cetorhinus maximus in the Caribbean Sea

    NARCIS (Netherlands)

    Geelhoed, S.C.V.; Janinhoff, N.; Verdaat, J.P.

    2016-01-01

    The occurrence of basking sharks in the Caribbean Sea is only recently documented by satellite tagging studies, which show that some individuals migrate through the region en route from waters off the east coast of the USA to waters off northeastern South-America. The observation of a basking shark

  10. Children's Perceptions of Sharks and Understanding of Its Ecological Significance for Educational Implications

    Science.gov (United States)

    Tsoi, Kwok Ho

    2011-01-01

    Global shark populations are seriously declining and many species are now threatened by anthropogenic stresses. Their extinction would cause devastating consequences to the marine biodiversity and ecosystems. However some children describe the sharks as bad guys, "we should kill them all!" Such children's view motivates my study…

  11. Whale sharks target dense prey patches of sergestid shrimp off Tanzania

    KAUST Repository

    Rohner, C. A.

    2015-03-17

    Large planktivores require high-density prey patches to make feeding energetically viable. This is a major challenge for species living in tropical and subtropical seas, such as whale sharks Rhincodon typus. Here, we characterize zooplankton biomass, size structure and taxonomic composition from whale shark feeding events and background samples at Mafia Island, Tanzania. The majority of whale sharks were feeding (73%, 380 of 524 observations), with the most common behaviour being active surface feeding (87%). We used 20 samples collected from immediately adjacent to feeding sharks and an additional 202 background samples for comparison to show that plankton biomass was ∼10 times higher in patches where whale sharks were feeding (25 vs. 2.6 mg m-3). Taxonomic analyses of samples showed that the large sergestid Lucifer hanseni (∼10 mm) dominated while sharks were feeding, accounting for ∼50% of identified items, while copepods (<2 mm) dominated background samples. The size structure was skewed towards larger animals representative of L.hanseni in feeding samples. Thus, whale sharks at Mafia Island target patches of dense, large, zooplankton dominated by sergestids. Large planktivores, such as whale sharks, which generally inhabit warm oligotrophic waters, aggregate in areas where they can feed on dense prey to obtain sufficient energy. © 2015 © The Author 2015. Published by Oxford University Press. All rights reserved.

  12. 75 FR 250 - Atlantic Highly Migratory Species; Atlantic Commercial Shark Management Measures

    Science.gov (United States)

    2010-01-05

    ... January 1, included: increased economic stability for Gulf of Mexico fishermen, increased market prices... helpful given the current economic situation in the country. Having the shark fishery open year round... shipping shark products in January, along with any other fish products, to other markets for economic...

  13. Observations on the whale shark (Rhincodon typus) in the Dutch Caribbean

    NARCIS (Netherlands)

    Debrot, A.O.; Leon, R.; Esteban, N.; Meesters, H.W.G.

    2013-01-01

    Records of whale sharks in the Caribbean are relatively sparse. Here we document 24 records of whale sharks (Rhincodon typus Smith 1882) for the Dutch Caribbean, four for the windward islands of Saba, St. Eustatius and St. Maarten, and twenty for the southern Caribbean leeward islands of Aruba,

  14. Age-related polychlorinated biphenyl dynamics in immature bull sharks (Carcharhinus leucas).

    Science.gov (United States)

    Olin, Jill A; Beaudry, Marina; Fisk, Aaron T; Paterson, Gordon

    2014-01-01

    Polychlorinated biphenyls (PCBs) were quantified in liver tissues of bull sharks (Carcharhinus leucas) ranging in age from 3 yr. Summed values of PCBs (ΣPCBs) ranged from 310 ng/g to 22 070 ng/g (lipid wt) across age classes with ΣPCB concentrations for the youngest sharks in the present study (3-yr-old sharks, highlighting the extent of exposure of this young life stage to this class of persistent organic pollutants (POPs). Age normalization of PCB congener concentrations to those measured for the youngest sharks demonstrated a significant hydrophobicity (log octanol/water partition coefficient [KOW ]) effect that was indicative of maternal offloading of highly hydrophobic (log KOW ≥6.5) congeners to the youngest individuals. A distinct shift in the PCB congener profiles was also observed as these young sharks grew in size. This shift was consistent with a transition from the maternally offloaded signal to the initiation of exogenous feeding and the contributions of mechanisms including growth dilution and whole-body elimination. These results add to the growing pool of literature documenting substantially high concentrations of POPs in juvenile sharks that are most likely attributable to maternal offloading. Collectively, such results underscore the potential vulnerability of young sharks to POP exposure and pose additional concerns for shark-conservation efforts. © 2013 SETAC.

  15. How Full Is Your Luggage? Background Knowledge of Zoo Visitors Regarding Sharks

    Science.gov (United States)

    das Neves, João Pedro Correia; Monteiro, Rute Cristina Rocha

    2013-01-01

    For the general population, sharks have a reputation that does not really fit with their biological and ecological nature. Informal surveys often classify sharks as dangerous, aggressive and/or man-eaters. This apparent common knowledge seems difficult to detach from the conscience of many worldwide zoo visitors, even with the help of…

  16. Ecological impact of the end-Cretaceous extinction on lamniform sharks.

    Science.gov (United States)

    Belben, Rachel A; Underwood, Charlie J; Johanson, Zerina; Twitchett, Richard J

    2017-01-01

    Lamniform sharks are apex marine predators undergoing dramatic local and regional decline worldwide, with consequences for marine ecosystems that are difficult to predict. Through their long history, lamniform sharks have faced widespread extinction, and understanding those 'natural experiments' may help constrain predictions, placing the current crisis in evolutionary context. Here we show, using novel morphometric analyses of fossil shark teeth, that the end-Cretaceous extinction of many sharks had major ecological consequences. Post-extinction ecosystems supported lower diversity and disparity of lamniforms, and were dominated by significantly smaller sharks with slimmer, smoother and less robust teeth. Tooth shape is intimately associated with ecology, feeding and prey type, and by integrating data from extant sharks we show that latest Cretaceous sharks occupied similar niches to modern lamniforms, implying similar ecosystem structure and function. By comparison, species in the depauperate post-extinction community occupied niches most similar to those of juvenile sand tigers (Carcharias taurus). Our data show that quantitative tooth morphometrics can distinguish lamniform sharks due to dietary differences, providing critical insights into ecological consequences of past extinction episodes.

  17. Evidence of positive selection associated with placental loss in tiger sharks.

    Science.gov (United States)

    Swift, Dominic G; Dunning, Luke T; Igea, Javier; Brooks, Edward J; Jones, Catherine S; Noble, Leslie R; Ciezarek, Adam; Humble, Emily; Savolainen, Vincent

    2016-06-14

    All vertebrates initially feed their offspring using yolk reserves. In some live-bearing species these yolk reserves may be supplemented with extra nutrition via a placenta. Sharks belonging to the Carcharhinidae family are all live-bearing, and with the exception of the tiger shark (Galeocerdo cuvier), develop placental connections after exhausting yolk reserves. Phylogenetic relationships suggest the lack of placenta in tiger sharks is due to secondary loss. This represents a dramatic shift in reproductive strategy, and is likely to have left a molecular footprint of positive selection within the genome. We sequenced the transcriptome of the tiger shark and eight other live-bearing shark species. From this data we constructed a time-calibrated phylogenetic tree estimating the tiger shark lineage diverged from the placental carcharhinids approximately 94 million years ago. Along the tiger shark lineage, we identified five genes exhibiting a signature of positive selection. Four of these genes have functions likely associated with brain development (YWHAE and ARL6IP5) and sexual reproduction (VAMP4 and TCTEX1D2). Our results indicate the loss of placenta in tiger sharks may be associated with subsequent adaptive changes in brain development and sperm production.

  18. Variation in depth of whitetip reef sharks: does provisioning ecotourism change their behaviour?

    Science.gov (United States)

    Fitzpatrick, Richard; Abrantes, Kátya G.; Seymour, Jamie; Barnett, Adam

    2011-09-01

    In the dive tourism industry, shark provisioning has become increasingly popular in many places around the world. It is therefore important to determine the impacts that provisioning may have on shark behaviour. In this study, eight adult whitetip reef sharks Triaenodon obesus were tagged with time-depth recorders at Osprey Reef in the Coral Sea, Australia. Tags collected time and depth data every 30 s. The absolute change in depth over 5-min blocks was considered as a proxy for vertical activity level. Daily variations in vertical activity levels were analysed to determine the effects of time of day on whitetip reef shark behaviour. This was done for days when dive boats were absent from the area, and for days when dive boats were present, conducting shark provisioning. Vertical activity levels varied between day and night, and with the presence of boats. In natural conditions (no boats present), sharks remained at more constant depths during the day, while at night animals continuously moved up and down the water column, showing that whitetip reef sharks are nocturnally active. When boats were present, however, there were also long periods of vertical activity during the day. If resting periods during the day are important for energy budgets, then shark provisioning may affect their health. So, if this behaviour alteration occurs frequently, e.g., daily, this has the potential to have significant negative effects on the animals' metabolic rates, net energy gain and overall health, reproduction and fitness.

  19. EFFECT OF FLUORIDE MOUTHRINSING ON CARIES LESION DEVELOPMENT IN SHARK ENAMEL - AN INSITU CARIES MODEL STUDY

    NARCIS (Netherlands)

    OGAARD, B; ROLLA, G; DIJKMAN, T; RUBEN, J; ARENDS, J

    1991-01-01

    Shark enamel consists of nearly pure fluorapatite and has been shown to demineralize in an in situ caries model. The present study was conducted to investigate whether additional fluoride supplementation in the form of mouthrinsing would inhibit lesion development in shark enamel. The study slabs of

  20. The shark assemblage at French Frigate Shoals atoll, Hawai'i: species composition, abundance and habitat use.

    Science.gov (United States)

    Dale, Jonathan J; Stankus, Austin M; Burns, Michael S; Meyer, Carl G

    2011-02-10

    Empirical data on the abundance and habitat preferences of coral reef top predators are needed to evaluate their ecological impacts and guide management decisions. We used longline surveys to quantify the shark assemblage at French Frigate Shoals (FFS) atoll from May to August 2009. Fishing effort consisted of 189 longline sets totaling 6,862 hook hours of soak time. A total of 221 sharks from 7 species were captured, among which Galapagos (Carcharhinus galapagensis, 36.2%), gray reef (Carcharhinus amblyrhynchos, 25.8%) and tiger (Galeocerdo cuvier, 20.4%) sharks were numerically dominant. A lack of blacktip reef sharks (Carcharhinus melanopterus) distinguished the FFS shark assemblage from those at many other atolls in the Indo-Pacific. Compared to prior underwater visual survey estimates, longline methods more accurately represented species abundance and composition for the majority of shark species. Sharks were significantly less abundant in the shallow lagoon than adjacent habitats. Recaptures of Galapagos sharks provided the first empirical estimate of population size for any Galapagos shark population. The overall recapture rate was 5.4%. Multiple closed population models were evaluated, with Chao M(h) ranking best in model performance and yielding a population estimate of 668 sharks with 95% confidence intervals ranging from 289-1720. Low shark abundance in the shallow lagoon habitats suggests removal of a small number of sharks from the immediate vicinity of lagoonal islets may reduce short-term predation on endangered monk seal (Monachus schauinslandi) pups, but considerable fishing effort would be required to catch even a small number of sharks. Additional data on long-term movements and habitat use of sharks at FFS are required to better assess the likely ecological impacts of shark culling.