938 resultados para Atlantic saury fishing
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The volume of the primary (PCS) and secondary (SCS) circulatory system in the Atlantic cod Gadus morhua was determined using a modified dye dilution technique. Cod (N=10) were chronically cannulated in the second afferent branchial artery with PE-50 tubing. Evans Blue dye was bound to harvested fish plasma at a concentration of 1 mg dye ml(-1) plasma, and injected at a concentration of 1 mg kg(-1) body mass. Serial sampling from the cannula produced a dye dilution curve, which could be described by a double exponential decay equation. Curve analysis enabled the calculation of the primary circulatory and total distribution volume. The difference between these volumes is assumed to be the volume of the SCS. From the dilution curve, it was also possible to calculate flow rates between and within the systems. The results of these experiments suggest a plasma volume in the PCS of 3.42+/-0.89 ml 100 g(-1) body mass, and in the SCS of 1.68+/-0.35 ml 100 g(-1) body mass (mean +/- S.D.) or approximately 50% that of the PCS. Flow rates to the SCS were calculated as 2.7% of the resting cardiac output. There was an allometric relationship between body mass and blood volumes. Increasing condition factor showed a tendency towards smaller blood volumes of the PCS, expressed as percentage body mass, but this was not evident for the volume of the SCS.
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Reportamos atividades de pesca comerciais no complexo insular mais afastado da costa brasileira: Ilha da Trindade e Arquipélago Martin Vaz. As atividades foram estudadas através de embarques e entrevistas com os mestres e pescadores das embarcações durante uma expedição cientifica realizada entre fevereiro e abril de 2007. Quatro modalidades de atividades de pesca são realizadas na região, capturando ao menos sete espécies que possuem algum risco de extinção. O estabelecimento de normas específicas de restrição para atividades que pescam sobre os recifes das ilhas é uma alternativa para a conservação das espécies ameaçadas. O monitoramento das embarcações pode ocorrer via satélite através do programa nacional de rastreamento de embarcações pesqueiras (PREPS).
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In the post-Cold War world, Africa has been an important focus of Brazilian foreign policy. Having a significant historical weight in building our nation, African countries are also part of the moves adopted by Brazil's foreign policy. The main purpose of the present text is to show this relevant regional dimension regarding Brazil's international insertion during the Lula era. The work is divided in two parts: the first part approaches Africa's international insertion throughout recent years and the second analyses the dimension occupied by African affairs in Brazil during the Lula era. The main argument is that the new role played by Africa in the international scene coincides with a global Brazil
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The objectives of this study were to identify anthophilous butterflies on psychophilous flowers of four Asteraceae species in an Atlantic Forest fragment in Viçosa, Minas Gerais State, Southeastern Brazil, and to determine whether there are species in common with other lepidopteran inventories of the Southeastern and Midwestern regions of Brazil. It is the first inventory of anthophilous butterflies of a semideciduous forest fragment in Zona da Mata, State of Minas Gerais. A total of 108 species were recorded, representing the fourth largest lepidopteran survey in this State. The results demonstrated that Asteraceae species may be important tools for monitoring anthophilous butterflies. The similarity with other inventories ranged from 1 to 92.55%. Fifteen species were reported for the first time in the State of Minas Gerais, and among them, Melanis alena and Thisbe irenea were observed in this study only.
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A discrete time, multi-gear, and age structured bio-economic model is developed for the East Atlantic bluefin tuna fisheries, a paradigmatic example of the difficulties faced in managing highly migratory fish stocks. The model is used to analyse alternative management strategies for the Regional Fisheries Management Organisation (RFMO) managing this fishery, and to investigate some of the policy implications. For the various scenarios, the optimal stock level varies between 500–800,000 tonnes, which compares with a stock level of 150,000 tonnes in 1995. In other words, there is a very strong case for rebuilding the stock. Moreover, the sustainability of the stock is threatened unless a recovery programme is implemented; indeed, the alternative may be stock collapse. Second, to rebuild the stock, Draconian measures are called for: either outright moratoria over fairly lengthy periods, or possibly a more gradual approach to steady state given by a Total Allowable Catch (TAC) at a low level for an extended period of time. Third, the cost of inefficient gear structure is very high indeed.
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P>Reconstruction of the South Atlantic opening has long been a matter of debate and several models have been proposed. One problem in tracing properly the Atlantic history arises from the existence of a long interval without geomagnetic reversals, the Cretaceous Normal Superchron, for which ages are difficult to assign. Palaeomagnetism may help in addressing this issue if high-quality palaeomagnetic poles are available for the two drifting continental blocks, and if precise absolute ages are available. In this work we have investigated the Cabo Magmatic Province, northeastern Brazil, recently dated at 102 +/- 1 Ma (zircon fission tracks, Ar39/Ar40). All volcanic and plutonic rocks showed stable thermal and AF demagnetization patterns, and exhibit primary magnetic signatures. AMS data also support a primary origin for the magnetic fabric and is interpreted to be contemporaneous of the rock formation. The obtained pole is located at 335.9 degrees E/87.9 degrees S (N = 24; A(95) = 2.5; K = 138) and satisfies modern quality criteria, resulting in a reference pole for South America at similar to 100 Ma. This new pole also gives an insight to test and discuss the kinematic models currently proposed for the South Atlantic opening during mid-Cretaceous.
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The Gulf of Cadiz coasts are exposed to tsunamis. Emergency planning tools are now taking into account this fact, especially because a series of historical occurrences were strikingly significant, having left strong evidence behind, in the mareographic records, the geological evidence or simply the memory of the populations. The study area is a strip along the Algarve coast, south Portugal, an area known to have been heavily impacted by the 1 November 1755 event. In this study we use two different tsunami scenarios generated by the rupture of two thrust faults identified in the area, corresponding to 8.1-8.3 magnitude earthquakes. Tsunami propagation and inundation computation is performed using a non-linear shallow water code with bottom friction. Numerical modeling results are presented in terms of flow depth and current velocity with maximum values of 7 m and 8 m/s for inundation depth and flow speed, respectively. These results constitute a valuable tool for local authorities, emergency and decision planners to define the priority zones where tsunami mitigation measures must be implemented and to develop tsunami-resilient communities.
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Eight marine cyanobacteria strains of the genera Cyanobium, Leptolyngbya, Oscillatoria, Phormidium, and Synechococcus were isolated from rocky beaches along the Atlantic Portuguese central coast and tested for ecotoxicity. Strains were identified by morphological characteristics and by the amplification and sequentiation of the 16S rDNA. Bioactivity of dichloromethane, methanol and aqueous extracts was assessed by the Artemia salina bioassay. Peptide toxin production was screened by matrix assisted laser desorption/ionization time of flight mass spectrometry. Molecular analysis of the genes involved in the production of known cyanotoxins such as microcystins, nodularins and cylindrospermopsin was also performed. Strains were toxic to the brine shrimp A. salina nauplii with aqueous extracts being more toxic than the organic ones. Although mass spectrometry analysis did not reveal the production of microcystins or other known toxic peptides, a positive result for the presence of mcyE gene was found in one Leptolyngbya strain and one Oscillatoria strain. The extensive brine shrimp mortality points to the involvement of other unknown toxins, and the presence of a fragment of genes involved in the cyanotoxin production highlight the potential risk of cyanobacteria occurrence on the Atlantic coast.
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The dusky grouper Epinephelus marginatus historically exploited by fisheries is a marine species showing slow growth, late maturation and protogynous hermaphroditism. Currently, it is considered as endangered by the IUCN. Therefore, it is essential to increase the knowledge about its biology and ecology to help conservation of this species. The present study reports the first record of a dusky grouper individual undergoing sexual transition, from female to male, in the Atlantic Ocean based on histological analyses of gonads. The specimen with total length: 770 mm; total weight: 8.1 kg and age: 21 years was captured in a rocky bottom along the coastline of the southernmost in Brazil.
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Jornadas "Ciência nos Açores – que futuro? Tema Ciências Naturais e Ambiente", Ponta Delgada, 7-8 de Junho de 2013.
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10th International Phycological Congress, Orlando, Florida, USA, 4-10 de agosto 2013.
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Jornadas "Ciência nos Açores – que futuro? Tema Ciências Naturais e Ambiente", Ponta Delgada, 7-8 de Junho de 2013.
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10th International Temperate Reefs Symposium, The University of Western Australia, 12-17 de janeiro.
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European Cetacean Society Conference Workshop, Galway, Ireland, 25th March 2012.