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Elasmobranch

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https://www.readbyqxmd.com/read/28924159/live-bearing-without-placenta-physical-estimation-indicates-the-high-oxygen-supplying-ability-of-white-shark-uterus-to-the-embryo
#1
Taketeru Tomita, Ryo Nozu, Masaru Nakamura, Shohei Matsuzaki, Kei Miyamoto, Keiichi Sato
One of the mysteries of shark aplacental viviparity is the ability of the embryos to acquire oxygen from their mothers without a placental connection. It has been assumed that embryonic respiration in aplacental viviparous shark depends on oxygen from the uterine wall, although this hypothesis has not been confirmed quantitatively. Morphological observations of the uterine wall of white shark (Carcharodon carcharias) provided the first quantitative evidence to support the ability of the uterus to supply ample oxygen to the embryo of viviparous elasmobranchs...
September 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28923557/a-molecular-approach-towards-taxonomic-identification-of-elasmobranch-species-from-maltese-fisheries-landings
#2
Adriana Vella, Noel Vella, Sarah Schembri
The mitochondrial genome, through the application of DNA barcoding, provides a powerful tool for identifying species even when specimens are either incomplete or belong to species that exhibit cryptic diversity. In fisheries management accurate identification of whole or part of the specimens landed is a fundamental requirement for the conservation of species affected directly or indirectly by the fisheries activities. In this study cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit 2 (ND2) sequences were used to genetically distinguish 36 elasmobranch species collected from Maltese (Central Mediterranean) commercial fisheries landings...
September 8, 2017: Marine Genomics
https://www.readbyqxmd.com/read/28923317/calcified-cartilage-or-bone-collagens-in-the-tessellated-endoskeletons-of-cartilaginous-fish-sharks-and-rays
#3
Ronald Seidel, Michael Blumer, Elisabeth-Judith Pechriggl, Kady Lyons, Brian K Hall, Peter Fratzl, James C Weaver, Mason N Dean
The primary skeletal tissue in elasmobranchs -sharks, rays and relatives- is cartilage, forming both embryonic and adult endoskeletons. Only the skeletal surface calcifies, exhibiting mineralized tiles (tesserae) sandwiched between a cartilage core and overlying fibrous perichondrium. These two tissues are based on different collagens (Coll II and I, respectively), fueling a long-standing debate as to whether tesserae are more like bone (Coll 1-based) or calcified cartilage in their matrix composition. We demonstrate that stingray (Urobatis halleri) tesserae are bipartite, having an upper Coll I-based "cap" that merges into a lower Coll II-based "body" zone, although tesserae are surrounded by cartilage...
September 15, 2017: Journal of Structural Biology
https://www.readbyqxmd.com/read/28887553/insight-into-shark-magnetic-field-perception-from-empirical-observations
#4
James M Anderson, Tamrynn M Clegg, Luisa V M V Q Véras, Kim N Holland
Elasmobranch fishes are among a broad range of taxa believed to gain positional information and navigate using the earth's magnetic field, yet in sharks, much remains uncertain regarding the sensory receptors and pathways involved, or the exact nature of perceived stimuli. Captive sandbar sharks, Carcharhinus plumbeus were conditioned to respond to presentation of a magnetic stimulus by seeking out a target in anticipation of reward (food). Sharks in the study demonstrated strong responses to magnetic stimuli, making significantly more approaches to the target (p = < 0...
September 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28882215/review-of-current-conservation-genetic-analyses-of-northeast-pacific-sharks
#5
Shawn E Larson, Toby S Daly-Engel, Nicole M Phillips
Conservation genetics is an applied science that utilizes molecular tools to help solve problems in species conservation and management. It is an interdisciplinary specialty in which scientists apply the study of genetics in conjunction with traditional ecological fieldwork and other techniques to explore molecular variation, population boundaries, and evolutionary relationships with the goal of enabling resource managers to better protect biodiversity and identify unique populations. Several shark species in the northeast Pacific (NEP) have been studied using conservation genetics techniques, which are discussed here...
2017: Advances in Marine Biology
https://www.readbyqxmd.com/read/28882214/age-and-growth-of-elasmobranchs-and-applications-to-fisheries-management-and-conservation-in-the-northeast-pacific-ocean
#6
Mary E Matta, Cindy A Tribuzio, David A Ebert, Kenneth J Goldman, Christopher M Gburski
In addition to being an academic endeavour, the practical purpose of conducting age and growth studies on fishes is to provide biological data to stock assessment scientists and fisheries managers so they may better understand population demographics and manage exploitation rates. Age and size data are used to build growth models, which are a critical component of stock assessments. Though age determination of elasmobranchs in the northeast Pacific Ocean (NEP) began in the 1930s, the field has evolved substantially in recent years, allowing scientists to incorporate age data into assessments for more species than ever before...
2017: Advances in Marine Biology
https://www.readbyqxmd.com/read/28882213/stable-isotope-applications-for-understanding-shark-ecology-in-the-northeast-pacific-ocean
#7
Jonathan C P Reum, Gregory D Williams, Chris J Harvey
Stable isotopes are used to address a wide range of ecological questions and can help researchers and managers better understand the movement and trophic ecology of sharks. Here, we review how shark studies from the Northeast Pacific Ocean (NEP) have employed stable isotopes to estimate trophic level and diet composition and infer movement and habitat-use patterns. To date, the number of NEP shark studies that have used stable isotopes is limited, suggesting that the approach is underutilized. To aid shark researchers in understanding the strengths and limitations of the approach, we provide a brief overview of carbon and nitrogen stable isotope trophic discrimination properties (e...
2017: Advances in Marine Biology
https://www.readbyqxmd.com/read/28841535/female-reproductive-traits-of-a-commercially-exploited-skate-atlantoraja-platana-g%C3%A3-nther-1880-chondrichthyes-rajidae-ovarian-morphology-gametogenesis-and-microscopic-verification-of-maturity-criteria
#8
A C Moya, A Wehitt, M C Díaz Andrade, E E Di Giacomo, E J Galíndez
Atlantoraja platana is an endemic species of the Southwest Atlantic Ocean, and is one of the most captured by the local bottom trawl industrial fisheries. In this work, the microscopic architecture of mature female's gonads and the dynamics of follicle development are studied as a contribution to raise awareness of reproductive biology of the species. Folliculogenesis depicts the same histologic pattern as in other Elasmobranchs. Follicles in different degrees of maturation coexist in mature animals. The oogonia were only found in immature individuals...
August 12, 2017: Micron: the International Research and Review Journal for Microscopy
https://www.readbyqxmd.com/read/28832664/neogene-sharks-and-rays-from-the-brazilian-blue-amazon
#9
Orangel Aguilera, Zoneibe Luz, Jorge D Carrillo-Briceño, László Kocsis, Torsten W Vennemann, Peter Mann de Toledo, Afonso Nogueira, Kamilla Borges Amorim, Heloísa Moraes-Santos, Marcia Reis Polck, Maria de Lourdes Ruivo, Ana Paula Linhares, Cassiano Monteiro-Neto
The lower Miocene Pirabas Formation in the North of Brazil was deposited under influence of the proto-Amazon River and is characterized by large changes in the ecological niches from the early Miocene onwards. To evaluate these ecological changes, the elasmobranch fauna of the fully marine, carbonate-rich beds was investigated. A diverse fauna with 24 taxa of sharks and rays was identified with the dominant groups being carcharhiniforms and myliobatiforms. This faunal composition is similar to other early Miocene assemblages from the proto-Carribbean bioprovince...
2017: PloS One
https://www.readbyqxmd.com/read/28810132/short-communication-alteration-in-blood-parameters-by-enrofloxacin-in-juvenile-lesser-spotted-dogfish-scyliorhinus-canicula-linnaeus-1758-after-intramuscular-injection
#10
Annalisa Zaccaroni, Marcos Perez-Lopez, Irene de la Casa Resino, Gianfranco Medri, Fabrizio Ceneri, Simone Bertini, Oliviero Mordenti, Luana Cortinovis, Rubina Sirri, Luciana Mandrioli
Enrofloxacin (EF) is a veterinary drug for respiratory, gastrointestinal and urinary tract infections. Parenteral administration at doses higher than the manufacturer recommended dosage has induced cartilage lesions in juvenile mammals and poultry. In elasmobranchs EF is commonly used for the treatment of infectious diseases, however only one study has been performed previously to evaluate pharmacokinetics and the potential chondrotoxicity of a fluoroquinolone in adult skates. In present study juvenile lesser spotted dogfish (Scyliorhinus canicula, Linnaeus, 1758) were treated with low (LD, 5mg/kg) and high dose (HD, 10mg/kg) of EF daily via intramuscular injection for 15 consecutive days, as indicated in a recognized treatment...
August 10, 2017: Research in Veterinary Science
https://www.readbyqxmd.com/read/28808540/who-s-my-daddy-considerations-for-the-influence-of-sexual-selection-on-multiple-paternity-in-elasmobranch-mating-systems
#11
Kady Lyons, Chris L Chabot, Christopher G Mull, Corinne N Paterson Holder, Christopher G Lowe
Polyandry resulting in multiply-sired litters has been documented in the majority of elasmobranch species examined to date. Although commonly observed, reasons for this mating system remain relatively obscure, especially in batoids. The round stingray (Urobatis halleri) is an abundant, well-studied elasmobranch distributed throughout the northeastern Pacific that we used to explore hypotheses regarding multiple paternity in elasmobranchs. Twenty mid- to late-term pregnant females were sampled off the coast of southern California and their litters analyzed for the occurrence of multiple paternity using five nuclear microsatellite loci...
August 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28807418/assessment-of-metallic-trace-elements-in-the-muscles-and-fins-of-four-landed-elasmobranchs-from-kuala-terengganu-waters-malaysia
#12
Meng Chuan Ong, Shi Ling Gan
A study had been carried out to determine Cu, Zn, Cd, Hg and Pb concentrations in the muscle and fins of four elasmobranchs species namely spot-tail sharks, milk sharks, whitespotted bamboo sharks and whitespotted guitarfish from Pulau Kambing LKIM Fishery Complex, Kuala Terengganu, Malaysia. Zinc level was found to have the highest concentration whereas Cd had the lowest concentration in both organs. By comparing both organs, metals concentrations in fins of all elasmobranchs species were higher than muscle...
August 11, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28760682/the-bulbus-arteriosus-of-the-holocephalan-heart-gross-anatomy-histomorphology-pigmentation-and-evolutionary-significance
#13
Cristina Rodríguez, Miguel Lorenzale, Miguel A López-Unzu, Borja Fernández, Francisca Salmerón, Valentín Sans-Coma, Ana C Durán
This study was designed to determine whether the outflow tract of the holocephalan heart is composed of a myocardial conus arteriosus and a non-myocardial bulbus arteriosus, as is the case in elasmobranchs. This is a key issue to verify the hypothesis that these two anatomical components existed from the onset of the jawed vertebrate radiation. The Holocephali are the sister group of the elasmobranchs, sharing with them a common, still unknown Palaeozoic ancestor. The sample examined herein consisted of hearts from individuals of four species, two of them belonging to the Chimaeridae and the other two to the Rhinochimaeridae...
June 3, 2017: Zoology: Analysis of Complex Systems, ZACS
https://www.readbyqxmd.com/read/28754065/acute-disseminated-mycobacteriosis-in-captive-atlantic-guitarfish-rhinobatos-lentiginosus
#14
Kathryn A Tuxbury, Samuel A Young, Daniel S Bradway, Jamie L Marola, Max Salfinger, Michael M Garner
An adult female captive-born Atlantic guitarfish ( Rhinobatos lentiginosus) was found acutely moribund on exhibit and died soon after presentation. Abnormalities on autopsy were focal cutaneous erythema on the tail, a small liver, many variably sized friable ovarian follicles, and coelomic effusion. Histologic examination revealed systemic bacterial embolization, and yolk coelomitis with minimal associated inflammation and some mineralization. Bacterial culture of blood and coelomic effusion grew a rapidly growing Mycobacterium species that was further identified as Mycobacterium chelonae by PCR amplification and sequencing of the RNA polymerase subunit beta ( rpoB) gene of isolated genomic DNA...
July 1, 2017: Journal of Veterinary Diagnostic Investigation
https://www.readbyqxmd.com/read/28725435/biogeophysical-and-physiological-processes-drive-movement-patterns-in-a-marine-predator
#15
Lucy A Howey, Bradley M Wetherbee, Emily R Tolentino, Mahmood S Shivji
BACKGROUND: Blue sharks (Prionace glauca) are among the most abundant and widely distributed of oceanic elasmobranchs. Millions are taken annually in pelagic longline fisheries and comprise the highest component of auctioned fin weight in the international shark fin trade. Though studies of blue sharks outnumber those of other large pelagic sharks, the species' complicated and sexually segregated life history still confound current understanding of Atlantic movement patterns. Lack of detailed information regarding movement and vertical behavior continues to limit management efforts that require such data for stock assessment and sustainable catch modeling...
2017: Movement Ecology
https://www.readbyqxmd.com/read/28725216/survey-of-antibiotic-producing-bacteria-associated-with-the-epidermal-mucus-layers-of-rays-and-skates
#16
Kim B Ritchie, Melbert Schwarz, Joseph Mueller, Valeri A Lapacek, Daniel Merselis, Catherine J Walsh, Carl A Luer
Elasmobranchs represent a distinct group of cartilaginous fishes that harbor a remarkable ability to heal wounds rapidly and without infection. To date very little work has addressed this phenomenon although it is suggested that antibiotic capabilities associated with epidermal surfaces may be a factor. The study of benefits derived from mutualistic interactions between unicellular and multicellular organisms is a rapidly growing area of research. Here we survey and identify bacterial associates of three ray and one skate species in order to assess the potential for antibiotic production from elasmobranch associated bacteria as a novel source for new antibiotics...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28712829/influence-of-ontogeny-and-environmental-exposure-on-mercury-accumulation-in-muscle-and-liver-of-male-round-stingrays
#17
Kady Lyons, Aaron B Carlisle, Christopher G Lowe
Mercury tissue distribution and its dynamics are poorly understood in elasmobranchs. Total mercury was measured in liver and muscle of male Round Stingrays (Urobatis halleri) from Seal Beach, California, an anthropogenically impacted site, and from the offshore island of Santa Catalina, a less impacted site. Stable isotope analysis was also performed on the muscle and red blood cells (RBCs) of a subset of rays over a range of age classes to investigate mercury accumulation with respect to trophic ecology. Mercury in both tissues was found to be significantly greater in adults than juveniles in mainland rays; however, liver mercury accumulation drastically increased after maturity and was significantly greater in mainland adult rays than Catalina rays...
July 4, 2017: Marine Environmental Research
https://www.readbyqxmd.com/read/28709399/draft-sequencing-and-assembly-of-the-genome-of-the-world-s-largest-fish-the-whale-shark-rhincodon-typus-smith-1828
#18
Timothy D Read, Robert A Petit, Sandeep J Joseph, Md Tauqeer Alam, M Ryan Weil, Maida Ahmad, Ravila Bhimani, Jocelyn S Vuong, Chad P Haase, D Harry Webb, Milton Tan, Alistair D M Dove
BACKGROUND: The whale shark (Rhincodon typus) has by far the largest body size of any elasmobranch (shark or ray) species. Therefore, it is also the largest extant species of the paraphyletic assemblage commonly referred to as fishes. As both a phenotypic extreme and a member of the group Chondrichthyes - the sister group to the remaining gnathostomes, which includes all tetrapods and therefore also humans - its genome is of substantial comparative interest. Whale sharks are also listed as an endangered species on the International Union for Conservation of Nature's Red List of threatened species and are of growing popularity as both a target of ecotourism and as a charismatic conservation ambassador for the pelagic ecosystem...
July 14, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28643409/variability-in-hematology-of-white-spotted-bamboo-sharks-chiloscyllium-plagiosum-in-different-living-environments
#19
Lily A Parkinson, Amy B Alexander, Terry W Campbell
Elasmobranch hematology continues to reveal new peculiarities within this specialized field. This report compares total hematologic values from the same white-spotted bamboo sharks (Chiloscyllium plagiosum) housed in different environments. We compared the hemograms one year apart, using a standardized Natt-Herrick's technique. The total white blood cell (WBC) counts of the sharks were statistically different between the two time points (initial median total WBC count = 18,920 leukocytes/μl, SD = 8,108; 1 year later total WBC count = 1,815 leukocytes/μl, SD = 1,309)...
June 22, 2017: Zoo Biology
https://www.readbyqxmd.com/read/28616238/validation-of-a-portable-waterproof-blood-ph-analyser-for-elasmobranchs
#20
Brendan Talwar, Ian A Bouyoucos, Oliver Shipley, Jodie L Rummer, John W Mandelman, Edward J Brooks, R Dean Grubbs
Quantifying changes in blood chemistry in elasmobranchs can provide insights into the physiological insults caused by anthropogenic stress, and can ultimately inform conservation and management strategies. Current methods for analysing elasmobranch blood chemistry in the field are often costly and logistically challenging. We compared blood pH values measured using a portable, waterproof pH meter (Hanna Instruments HI 99161) with blood pH values measured by an i-STAT system (CG4+ cartridges), which was previously validated for teleost and elasmobranch fishes, to gauge the accuracy of the pH meter in determining whole blood pH for the Cuban dogfish (Squalus cubensis) and lemon shark (Negaprion brevirostris)...
2017: Conservation Physiology
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