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https://www.readbyqxmd.com/read/28438339/mercury-arsenic-cadmium-and-lead-in-two-commercial-shark-species-sphyrna-lewini-and-caraharinus-porosus-in-trinidad-and-tobago
#1
Azad Mohammed, Terry Mohammed
Sharks are long-lived apex predators which can accumulate toxic metals such as mercury and arsenic. Samples of Sphyrna lewini and Carcharinus porosus were collected from two commercial fish landing sites in Trinidad. Heavy metal concentrations were determined in the muscle, dorsal fin, vertebrae and liver using atomic absorption spectrometric. The provisional tolerable weekly intake (PTWI) and target hazard quotient (THQ) were determined to assess the potential health risks to consumers. Mercury levels ranged between 74-1899μg/kg in S...
April 21, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28432307/arsenic-metabolism-in-high-altitude-modern-stromatolites-revealed-by-metagenomic-analysis
#2
Daniel Kurth, Ariel Amadio, Omar F Ordoñez, Virginia H Albarracín, Wolfgang Gärtner, María E Farías
Modern stromatolites thrive only in selected locations in the world. Socompa Lake, located in the Andean plateau at 3570 masl, is one of the numerous extreme Andean microbial ecosystems described over recent years. Extreme environmental conditions include hypersalinity, high UV incidence, and high arsenic content, among others. After Socompa's stromatolite microbial communities were analysed by metagenomic DNA sequencing, taxonomic classification showed dominance of Proteobacteria, Bacteroidetes and Firmicutes, and a remarkably high number of unclassified sequences...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28430794/experimental-demonstration-of-a-trophic-cascade-in-the-gal%C3%A3-pagos-rocky-subtidal-effects-of-consumer-identity-and-behavior
#3
Jon D Witman, Franz Smith, Mark Novak
In diverse tropical webs, trophic cascades are presumed to be rare, as species interactions may dampen top-down control and reduce their prevalence. To test this hypothesis, we used an open experimental design in the Galápagos rocky subtidal that enabled a diverse guild of fish species, in the presence of each other and top predators (sea lions and sharks), to attack two species of sea urchins grazing on benthic algae. Time-lapse photography of experiments on natural and experimental substrates revealed strong species identity effects: only two predator species-blunthead triggerfish (Pseudobalistes naufragium) and finescale triggerfish (Balistes polylepis)-drove a diurnal trophic cascade extending to algae, and they preferred large pencil urchins (Eucidaris galapagensis) over green urchins (Lytechinus semituberculatus)...
2017: PloS One
https://www.readbyqxmd.com/read/28429742/crossing-lines-a-multidisciplinary-framework-for-assessing-connectivity-of-hammerhead-sharks-across-jurisdictional-boundaries
#4
A Chin, C A Simpfendorfer, W T White, G J Johnson, R B McAuley, M R Heupel
Conservation and management of migratory species can be complex and challenging. International agreements such as the Convention on Migratory Species (CMS) provide policy frameworks, but assessments and management can be hampered by lack of data and tractable mechanisms to integrate disparate datasets. An assessment of scalloped (Sphyrna lewini) and great (Sphyrna mokarran) hammerhead population structure and connectivity across northern Australia, Indonesia and Papua New Guinea (PNG) was conducted to inform management responses to CMS and Convention on International Trade in Endangered Species listings of these species...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28424102/gaining-insights-into-the-ecological-role-of-the-new-zealand-sole-peltorhamphus-novaezeelandiae-through-parasites
#5
T Anglade, H S Randhawa
Despite the fact that tapeworms comprise the bulk of parasite communities of sharks in marine ecosystems, little is known about their life cycles and, more specifically, about the potential intermediate hosts they utilize as transmission routes. In the absence of morphological features required for specific identification of larval tapeworms from potential intermediate hosts, recent molecular advances have contributed to linking larval and adult parasites and, in some instances, uncovering unknown trophic links...
April 20, 2017: Journal of Helminthology
https://www.readbyqxmd.com/read/28423077/early-devonian-late-emsian-shark-fin-remains-chondrichthyes-from-the-paran%C3%A3-basin-southern-brazil
#6
Martha Richter, Elvio P Bosetti, Rodrigo S Horodyski
We report on the pioneering discovery of Devonian fish remains in the Paraná Basin, which represents the southernmost record of fishes from that period in mainland South America. The material comes from an outcrop at the lower portion of the São Domingos Formation, within Sequence C of the Paraná-Apucarana sub-basin in Tibagi, State of Paraná. Marine invertebrates are abundant in the same strata. The dark colored fish remains were collected in situ and represent natural moulds of partially articulated shark fin rays (radials)...
January 2017: Anais da Academia Brasileira de Ciências
https://www.readbyqxmd.com/read/28422965/diet-and-condition-of-mesopredators-on-coral-reefs-in-relation-to-shark-abundance
#7
Shanta C Barley, Mark G Meekan, Jessica J Meeuwig
Reef sharks may influence the foraging behaviour of mesopredatory teleosts on coral reefs via both risk effects and competitive exclusion. We used a "natural experiment" to test the hypothesis that the loss of sharks on coral reefs can influence the diet and body condition of mesopredatory fishes by comparing two remote, atoll-like reef systems, the Rowley Shoals and the Scott Reefs, in northwestern Australia. The Rowley Shoals are a marine reserve where sharks are abundant, whereas at the Scott Reefs numbers of sharks have been reduced by centuries of targeted fishing...
2017: PloS One
https://www.readbyqxmd.com/read/28422134/genetic-structure-and-signatures-of-selection-in-grey-reef-sharks-carcharhinus-amblyrhynchos
#8
P Momigliano, R Harcourt, W D Robbins, V Jaiteh, G N Mahardika, A Sembiring, A Stow
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)...
April 19, 2017: Heredity
https://www.readbyqxmd.com/read/28418094/the-skin-microbiome-of-the-common-thresher-shark-alopias-vulpinus-has-low-taxonomic-and-potential-metabolic-%C3%AE-diversity
#9
Michael P Doane, John Matthew Haggerty, Dovi Kacev, Bhavya Papudeshi, Elizabeth A Dinsdale
The health of sharks is linked with emergent properties of its microbiome. Most marine organisms have mucus overlying the skin, but shark have dermal denticles that protrude above the mucus. We characterized the microbiome from the skin of the common thresher shark (Alopias vulpinus) to investigate the structure and composition of the skin microbiome. An average of 618,812 reads per metagenomic library contained open reading frames (80.9% ± S.D. 0.44%), and 7.6 to 12.8% matched known protein sequences...
April 18, 2017: Environmental Microbiology Reports
https://www.readbyqxmd.com/read/28407022/gap-analysis-on-the-biology-of-mediterranean-marine-fishes
#10
Donna Dimarchopoulou, Konstantinos I Stergiou, Athanassios C Tsikliras
We estimated the current level of knowledge concerning several biological characteristics of the Mediterranean marine fishes by carrying out a gap analysis based on information extracted from the literature, aiming to identify research trends and future needs in the field of Mediterranean fish biology that can be used in stock assessments, ecosystem modeling and fisheries management. Based on the datasets that emerged from the literature review, there is no information on any biological characteristic for 43% (n = 310) of the Mediterranean fish species, whereas for an additional 15% (n = 109) of them there is information about just one characteristic...
2017: PloS One
https://www.readbyqxmd.com/read/28406963/historical-and-ecological-drivers-of-the-spatial-pattern-of-chondrichthyes-species-richness-in-the-mediterranean-sea
#11
María José Meléndez, José Carlos Báez, José Miguel Serna-Quintero, Juan Antonio Camiñas, Ignacio de Loyola Fernández, Raimundo Real, David Macías
Chondrichthyes, which include Elasmobranchii (sharks and batoids) and Holocephali (chimaeras), are a relatively small group in the Mediterranean Sea (89 species) playing a key role in the ecosystems where they are found. At present, many species of this group are threatened as a result of anthropogenic effects, including fishing activity. Knowledge of the spatial distribution of these species is of great importance to understand their ecological role and for the efficient management of their populations, particularly if affected by fisheries...
2017: PloS One
https://www.readbyqxmd.com/read/28406176/male-alliance-behaviour-and-mating-access-varies-with-habitat-in-a-dolphin-social-network
#12
Richard C Connor, William R Cioffi, Srđan Randić, Simon J Allen, Jana Watson-Capps, Michael Krützen
Within-species variation in social structure has attracted interest recently because of the potential to explore phenotypic plasticity and, specifically, how demographic and ecological variation influence social structure. Populations of bottlenose dolphins (Tursiops spp.) vary in male alliance formation, from no alliances to simple pairs to, in Shark Bay, Western Australia, the most complex nested alliances known outside of humans. Examination of ecological contributions to this variation is complicated by differences among populations in other potentially explanatory traits, such as phylogenetic distance, as well as female reproductive schedules, sexual size dimorphism, and body size...
April 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28405277/a-hidden-markov-movement-model-for-rapidly-identifying-behavioral-states-from-animal-tracks
#13
Kim Whoriskey, Marie Auger-Méthé, Christoffer M Albertsen, Frederick G Whoriskey, Thomas R Binder, Charles C Krueger, Joanna Mills Flemming
Electronic telemetry is frequently used to document animal movement through time. Methods that can identify underlying behaviors driving specific movement patterns can help us understand how and why animals use available space, thereby aiding conservation and management efforts. For aquatic animal tracking data with significant measurement error, a Bayesian state-space model called the first-Difference Correlated Random Walk with Switching (DCRWS) has often been used for this purpose. However, for aquatic animals, highly accurate tracking data are now becoming more common...
April 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28400049/species-co-occurrence-affects-the-trophic-interactions-of-two-juvenile-reef-shark-species-in-tropical-lagoon-nurseries-in-moorea-french%C3%A2-polynesia
#14
Philip Matich, Jeremy J Kiszka, Johann Mourier, Serge Planes, Michael R Heithaus
Food web structure is shaped by interactions within and across trophic levels. As such, understanding how the presence and absence of predators, prey, and competitors affect species foraging patterns is important for predicting the consequences of changes in species abundances, distributions, and behaviors. Here, we used plasma δ(13)C and δ(15)N values from juvenile blacktip reef sharks (Carcharhinus melanopterus) and juvenile sicklefin lemon sharks (Negaprion acutidens) to investigate how species co-occurrence affects their trophic interactions in littoral waters of Moorea, French Polynesia...
March 28, 2017: Marine Environmental Research
https://www.readbyqxmd.com/read/28398352/x-ray-computed-tomography-library-of-shark-anatomy-and-lower-jaw-surface-models
#15
Pepijn Kamminga, Paul W De Bruin, Jacob Geleijns, Martin D Brazeau
The cranial diversity of sharks reflects disparate biomechanical adaptations to feeding. In order to be able to investigate and better understand the ecomorphology of extant shark feeding systems, we created a x-ray computed tomography (CT) library of shark cranial anatomy with three-dimensional (3D) lower jaw reconstructions. This is used to examine and quantify lower jaw disparity in extant shark species in a separate study. The library is divided in a dataset comprised of medical CT scans of 122 sharks (Selachimorpha, Chondrichthyes) representing 73 extant species, including digitized morphology of entire shark specimens...
April 11, 2017: Scientific Data
https://www.readbyqxmd.com/read/28397816/dynamics-of-archaea-at-fine-spatial-scales-in-shark-bay-mat-microbiomes
#16
Hon Lun Wong, Pieter T Visscher, Richard Allen White Iii, Daniela-Lee Smith, Molly M Patterson, Brendan P Burns
The role of archaea in microbial mats is poorly understood. Delineating the spatial distribution of archaea with mat depth will enable resolution of putative niches in these systems. In the present study, high throughput amplicon sequencing was undertaken in conjunction with analysis of key biogeochemical properties of two mats (smooth and pustular) from Shark Bay, Australia. One-way analysis of similarity tests indicated the archaeal community structures of smooth and pustular mats were significantly different (global R = 1, p = 0...
April 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28394411/an-upstream-migration-fought-with-danger-freshwater-sawfish-fending-off-sharks-and-crocodiles
#17
David L Morgan, Ruchira Somaweera, Adrian C Gleiss, Stephen J Beatty, Jeff M Whitty
No abstract text is available yet for this article.
April 10, 2017: Ecology
https://www.readbyqxmd.com/read/28387231/corrigendum-switch-from-sexual-to-parthenogenetic-reproduction-in-a-zebra-shark
#18
Christine L Dudgeon, Laura Coulton, Ren Bone, Jennifer R Ovenden, Severine Thomas
No abstract text is available yet for this article.
April 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28386422/horizontal-and-vertical-movements-of-caribbean-reef-sharks-carcharhinus-perezi-conservation-implications-of-limited-migration-in-a-marine-sanctuary
#19
Oliver N Shipley, Lucy A Howey, Emily R Tolentino, Lance K B Jordan, Jonathan L W Ruppert, Edward J Brooks
Despite the ecological and economic importance of the Caribbean reef shark (Carcharhinus perezi), little data exist regarding the movements and habitat use of this predator across its range. We deployed 11 pop-up satellite archival tags on Caribbean reef sharks captured in the northeast Exuma Sound, The Bahamas, to assess their horizontal and vertical movements throughout the water column. Sharks showed high site fidelity to The Bahamas suggesting Bahamian subpopulations remain protected within the Bahamian Shark Sanctuary...
February 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28381626/risky-business-for-a-juvenile-marine-predator-testing-the-influence-of-foraging-strategies-on-size-and-growth-rate-under-natural-conditions
#20
Nigel E Hussey, Joseph D DiBattista, Jonathan W Moore, Eric J Ward, Aaron T Fisk, Steven Kessel, Tristan L Guttridge, Kevin A Feldheim, Bryan R Franks, Samuel H Gruber, Ornella C Weideli, Demian D Chapman
Mechanisms driving selection of body size and growth rate in wild marine vertebrates are poorly understood, thus limiting knowledge of their fitness costs at ecological, physiological and genetic scales. Here, we indirectly tested whether selection for size-related traits of juvenile sharks that inhabit a nursery hosting two dichotomous habitats, protected mangroves (low predation risk) and exposed seagrass beds (high predation risk), is influenced by their foraging behaviour. Juvenile sharks displayed a continuum of foraging strategies between mangrove and seagrass areas, with some individuals preferentially feeding in one habitat over another...
April 12, 2017: Proceedings. Biological Sciences
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