556 resultados para Macrófita aquática
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The larval instars, seasonal occurrence and environmental factors influence on Psaroniocompsa incrustata (Lutz, 1910) (Diptera: Simuliidae) immature were studied according to its physical and chemical aspects of breeding water. Four collects were made at vegetal substrate from margin, middle and floating on the Pium river, city of Nísia Floresta, state of Rio Grande do Norte, Brazil at dry and wet season. Some of larval characters were used to determinate the larval instars number like lateral length of cephalic capsulae, antennae and the distance among cephalic apodema, as well as pH, water temperature, width, depth, stream velocity, discharge and pluviometric precipitation were used for physical factors. Seven larval instars were determined for this P. incrustata community being the lateral length of cephalic capsulae as the best structure with this meaning propose. The seasonality immature abundance of this species were found in dry season and a positive correlation with pH, stream velocity and precipitation
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The species psaroniocompsa incrustata (Lutz, 1910) was studied in relation to its abundance in different and seasonal periods, the physico-chemical of the breending ground and the fauna predation added to the immature of the species. The study was developed during eight months, from April to July, 2005 (rainy season) and from October, 2005 to January, 2006 (drought season), in one natural breending ground situated in the Pium river, that is part of the hydrographical basin of the Pirangi river in Rio Grande do Norte. The immature of Simuliidae were collected manually in vegetal substrate. At the same place, it was made one sampling of the associated fauna using Suber collectors and the measurement of the environment variants. It was also made one analysis of the stomach content of possible enemies of the simulídeos, to observe the predation of the associated fauna. It was collected 7.713 samples, all from de species P. Incrustata, it was observed a bigger abundance in the drought season, and the entomologic fauna associated totalizing 20.1314 species, distributed in the kinds: Diptera, Ephemeroptera, Odonata, Trichoptera, e Hemiptera, with a bigger representativity of Dipteros. The analysis of the stomach content of the species from the families Libellulidae and Hydropsychidae showed the presence of the simulídeos in only 4% of the material analysed, therefore it was not confirmed the presence of one efficient biological control of the simulídeos in this breending ground
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The current study examined spatial-temporal modifications and water quality through chemical and biotic indicators during both dry (January, February and November 2006) and wet seasons (March to June 2006). This study was carried out in Armando Ribeiro Gonçalves Reservoir, RN, Canal do Pataxó and after the water station treatment (WST). The physical-chemical parameters were measured in situ and inorganic nutrients, chlorophyll a and Free Oxygen Demand (FOD) were analyzed in laboratory conditions. Quali quantitative analyses of phytoplankton were carried out utilizing Sedgwick-Rafter camera. Results indicate that DQO concentrations were low. FOD concentrations in the reservoir were comparatively higher in the dry season (5.21 mgL-1; 5.64 mgL-1 e 6.05 mgL-1) in relation to the wet season (4.52 mgL-1; 4.12 mgL-1 e 4.92 mgL-1), in surface, intermediate and bottom waters, respectively. FOD values were inferior to 1.0mgL-1in both Canal do Pataxó and after WST, which is considered adequate for public use reservoirs. Although FOD concentrations were low, Armando Ribeiro Gonçalves Reservoir, Canal do Pataxó and WST were classified as euthophizied, mesotrophic ad oligotrophic, respectively, considering the Index of Trophic State Criteria. Chlorophyll a concentrations in the study reservoir were higher in the surface (199.2 µgL-1) during the wet season, whereas in Canal do Pataxó concentrations decreased from 1.56 µgL-1 to 0.028 µgL-1, and after WST values were low (0.059 µgL-1). Dominance of cianobacterias, such as Planktotrhix agardhii (dry season) and Microcystis sp (wet season) was registered in all three areas. In the reservoir and Canal do Pataxó, density of cianobacterias, such as P. agardhii and Microcistys sp., was superior to the values allowed by the Health ministry (HM). However, after WST, density values of cianobacteria were inferior to values established by the HM
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The response of zooplankton assemblages to variations in the water quality of four man-made lakes, caused by eutrophication and siltation, was investigated by means of canonical correspondence analysis. Monte Carlo simulations using the CCA eingenvalues as test statistics revealed that changes in zooplankton species composition along the environmental gradients of trophic state and abiogenic turbidity were highly significant. The species Brachionus calyciflorus, Thermocyclops sp. and Argyrodiaptomus sp. were good indicators of eutrophic conditions while the species Brachionus dolabratus, Keratella tropica and Hexarthra sp. were good indicators of high turbidity due to suspended sediments. The rotifer genus Brachionus was the most species-rich taxon, comprising five species which were associated with different environmental conditions. Therefore, we tested whether this genus alone could potentially be a better biological indicator of these environmental gradients than the entire zooplankton assemblages or any other random set of five species. The ordination results show that the five Brachionus species alone did not explain better the observed pattern of environmental variation than most random sets of five species. Therefore, this genus could not be selected as a target taxon for more intensive environmental monitoring as has been previously suggested by Attayde and Bozelli (1998). Overall, our results show that changes in the water quality of man-made lakes in a tropical semi-arid region have significant effects on the structure of zooplankton assemblages that can potentially affect the functioning of these ecosystems
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The expansion of shrimp farming has caused a series of environmental impacts, often as a result of lack of planning and adequate management. Organic aquaculture has emerged as an alternative to conventional shrimp farming, and differently, aims at the economical, ecological and farming potential of other organisms, such as fishes, oysters and seaweeds. The present study aimed at evaluating the biological diversity and abundance of the ichthyofauna associated to Litopenaeus vannamei organic culture at PRIMAR farm (Rio Grande do Norte, Brazil). The sampling period consisted of four culture cycles (1, 2, 3, and 4) accomplished in four grow-out ponds (V1, V7, V2, and V4) in 2005. The first two culture cycles were carried out during the rainy season, and the last two cycles, during the dry season. Environmental (temperature, salinity, transparency, and rainfall), biodiversity (diversity and uniformity and abundance indexes) of the ichthyofauna, and shrimp productivity data were collected throughout these four culture cycles. The results obtained for the environmental variables showed that both salinity and transparency oscillated in a significant way (p < 0.001) between culture cycles. In relation to the abundance of the ichthyofauna, fifty four species associated to the organic culture of Litopenaeus vannamei were collected and identified at PRIMAR. For the biodiversity criterion, larger species richness (S = 46) and uniformity (E = 0.59 ± 0.16) were observed during cycles 3 and 4 than in cycles 1 and 2 (S = 41 and E = 0.15 ± 0.12). A positive and significant correlation was obtained for the transparency with diversity and uniformity of fish species between cycles 1 and 2 (wet season) and cycles 3 and 4 (dry season) (p < 0.017 - Shannon Index; p < 0.008 - Pielou Index, respectively). A correlation could not be established between shrimp productivity and fish biomass. However, fish biomass decreased from cycles 1 and 2 to cycles 3 and 4, concomitant with an increase in shrimp productivity, most probably due to a higher (from 58.0% to 71.0%) shrimp survival. Regarding the culture potential of the ichthyofauna, three species (Mugil curema, Mugil liza and Chaetodipterus faber) were identified as potential farming alternatives, either singly or in consortium with Litopenaeus vannamei. A fourth species (Centropomus undecimalis) was indicated as an alternative for single culture or in consortium with other fish species. In conclusion, the large diversity of estuarine fishes associated to Litopenaeus vannamei farming observed at PRIMAR clearly indicated the ecological feasibility for organic aquaculture in northeastern Brazil
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Artificial lakes must differ from natural lakes in important structural and functional aspects that need to be understood so that these ecosystems can be properly managed. The aim of this work was to test the hypothesis that the artificial lakes (impoundments) in the semi-arid region of the Rio Grande do Norte State are more eutrophic and turbid and have different trophic structure when compared to the natural coastal lakes that occur in the humid eastern coast of the State. To test this hypothesis, 10 natural lakes and 8 artificial lakes with about 100 ha were sampled between September and November 2005 for the determination of some limnological variables and the abundance of the main fish species, which were grouped in three trophic guilds: facultative piscivores, facultative planktivores and omnivores. The results show that the artificial lakes had significantly higher concentrations of total nitrogen, total phosphorus, chlorophyll a , total and volatile suspended solids than the natural lakes. Results also show that the values of pH, total alkalinity, electric conductivity, turbidity as well as the coefficient of vertical attenuation of light were significantly higher in the artificial lakes than in the natural lakes. In the artificial lakes, the abundance of facultative planktivores was significantly higher, while the abundance of facultative piscivores significantly lower than in the natural lakes. There was no significant difference in the abundance of omnivorous fish between the two types of lakes. These results suggest that the increase in turbidity together with the other changes in the water quality of the artificial lakes, modifies the trophic structure of the fish communities reducing the importance of piscivores and the length of the food chains
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Since centuries ago, the Asians use seaweed as an important source of feeding and are their greatest world-wide consumers. The migration of these peoples for other countries, made the demand for seaweed to increase. This increasing demand prompted an industry with annual values of around US$ 6 billion. The algal biomass used for the industry is collected in natural reservoirs or cultivated. The market necessity for products of the seaweed base promotes an unsustainable exploration of the natural banks, compromising its associated biological balance. In this context, seaweed culture appears as a viable alternative to prevent the depletion of these natural supplies. Geographic Information Systems (GIS) provide space and produce information that can facilitate the evaluation of important physical and socio-economic characteristics for the planning of seaweed culture. This objective of this study is to identify potential coastal areas for seaweed culture in the state of Rio Grande do Norte, from the integration of social-environmental data in the SIG. In order to achieve this objective, a geo-referred database composed of geographical maps, nautical maps and orbital digital images was assembled; and a bank of attributes including physical and oceanographical variables (winds, chains, bathymetry, operational distance from the culture) and social and environmental factors (main income, experience with seaweed harvesting, demographic density, proximity of the sheltered coast and distance of the banks) was produced. In the modeling of the data, the integration of the space database with the bank of attributes for the attainment of the map of potentiality of seaweed culture was carried out. Of a total of 2,011 ha analyzed by the GIS for the culture of seaweed, around 34% or 682 ha were indicated as high potential, 55% or 1,101 ha as medium potential, and 11% or 228 ha as low potential. The good indices of potentiality obtained in the localities studied demonstrate that there are adequate conditions for the installation of seaweed culture in the state of Rio Grande do Norte
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We present a checklist of the shores fishes of the coast of the Rio Grande do Norte state. Species were registered through the specimens collection, underwater records, samples in landings of artisanal fleet and by compilation of data from literature and ichthyologic collections, between January 2004 to 2006. A total of 440 species form 2 classes, 25 orders, 106 families and 253 genus were registered. It is believed that due the great increase of the number of species registered, the ichthyofauna of the coast of this state is reasonably known
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2016
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O presente trabalho consiste na apresentação da diversidade de seláceos do Farol das Lagostas pertencente à Bacia do Cuanza. Os condrichthyes são componentes comuns da fauna aquática desde o Paleozoico. No entanto, devido à natureza cartilaginosa do esqueleto, o registo paleontológico dos mesmos restringe-se, basicamente, às partes mineralizadas como dentes, dentículos dérmicos e espinhas cefálicas O lugar Farol das Lagostas contém uma fauna de seláceos relativamente rica e variada, representada neste estudo por cerca de 1.000 dentes isolados, além de outras peças esqueléticas. Foram identificados e descritos quarenta e quatro taxa, pertencentes às seguintes ordens: Hexanchiformes, Squaliformes, Pristiophoriformes, Squatiniformes, Lamniformes, Carcharhiniformes, Rajiformes e Myliobatiformes. Trata-se de uma diversidade faunística cuja maioria dos géneros possui representantes atuais. Os Carcharhiniformes representam 53% dos taxa identificados. Estão representadas as famílias Scyliorhinidae, Triakidae, Hemigaleidae, Carcharhinidae e Sphyrnidae, com 18 espécies. Verifica-se a presença de formas bentónicas e nectónicas que indicam condições térmicas moderadas, quentes e tropicais a temperadas, que habitam frequentemente zonas costeiras. A relação faunística identificada corresponde a uma zona litoral. Ora, considerando o conjunto de dados em face da presença de fauna pelágica e dos grandes predadores, especialmente Isurus hastalis e Carcharocles megalodon, podemos admitir que existisse então um Golfo relativamente largo de uma faixa Atlântica aberta (Antunes & Balbino, 2004); ABSTRACT: Selachians from Farol the Lagostas (Cuanza Basin, Angola) The present work consists of the presentation of diversity of selachians from Farol das Lagostas, which belongs to the Cuanza Basin. The condrichthyes are a part of aquatic fauna since the Paleozoic. However, due to the nature of the cartilaginous skeleton, the paleontological registration of the same ones is restricted to mineralized parts like teeth, dermal denticles and cephalic spines. The of formation, Farol das Lagostas has a fauna of selachian relatively rich and diverse, represented in this study for around 1.000 isolated teeth, and other skeletal parts. Forty four taxa were described and identified, belonging to the following orders: Hexanchiformes, Squaliformes, Pristiophoriformes, Squatiniformes, Lamniformes, Carcharhiniformes, Rajiformes e Myliobatiformes. It’s a faunal diversity whose most genera have current representatives. The Carcharhiniformes represente 53% of the identified taxa. The represented families are Scyliorhinidae, Triakidae, Hemigaleidae, Carcharhinidae e Sphyrnidae, with 18 species. There is presence of benthic and nektonic forms that indicate moderate thermal conditions, the temperate and tropical hot, often inhabit coastal areas. The identified faunal relation corresponds to a coastal zone. So, considering the data set, due to the presence of pelagic fauna and large predators, especially Isurus hastalis e Carcharocles megalodon, we can admit that then there was a relatively large Gulf of open Atlantic range (Antunes & Balbino, 2004).
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Foram testados os efeitos, in vitro, de 160, 320, 640, 1280 e 2560 mg/L do óleo essencial (OE) de Lippia alba contra Anacanthorus spathulatus, Notozothecium janauachensis e Mymarothecium boegeri das brânquias de tambaqui. 1280 mg/L e 2560 mg/L mostraram 100% de eficácia in vitro após 20 minutos de exposição ao OE, enquanto nas menores concentrações a eficácia foi após 2-3 h. Nos controles a mortalidade ocorreu em 9 h. Em seguida, 240 alevinos de tambaqui Colossoma macropomum (11,0±1,0 cm e 44,0±10,0 g) foram distribuídos em 4 tratamentos (20 peixes por repetição) e 3 repetições nos banhos com 100 e 150 mg/L de OE, durante 30 minutos e a eficácia contra Ichthyophthirius multifiliis foi 40,7% e 50,3% em peixes expostos a 100 e 150 mg/L do OE, respectivamente. Para monogenoideas houve eficácia de 14,0% somente nos peixes expostos a 100 mg/L do OE, que tiveram aumento de glicose plasmática e variações nos níveis de proteínas totais, hemoglobina, hematócrito, número de eritrócitos, trombócitos e leucócitos sanguíneos e severas alterações histopatológicas nas brânquias. Óleo essencial de L. alba mostrou grande potencial no tratamento antiparasitário in vitro contra monogenoideas e eficácia in vivo contra protozoários I. multifiliis.
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O uso de probióticos na alimentação dos peixes pode estimular o sistema imunológico e agir na prevenção de enfermidades. O presente estudo avaliou a fisiologia de pirarucu Arapaima gigas após alimentação por 30 dias com dietas enriquecidas com probiótico Bacillus subtilis em 3 níveis de inclusão: 0 (Controle); 0,02 (BS0,02%) e 0,05% (BS0,05%) (triplicata), sendo realizada biometria e coleta de amostras de sangue. Os grupos foram comparados entre si (P<0,05). O peso, comprimento e o índice hepatossomático (IHS) dos pirarucus BS0,05% foram menores que os do Controle. As análises hematológicas e bioquímicas indicaram que BS0,02% promoveu aumento do hematócrito e da albumina, com relação aos demais grupos; e diminuição da concentração de hemoglobina corpuscular média (CHCM) e da glicose plasmática com relação ao Controle. A hemoglobina corpuscular média (HCM) e atividade respiratória dos leucócitos do BS0,05% diminuíram com relação ao Controle. BS0,02% apresentaram redução do número de leucócitos, com relação ao Controle, que refletiu na diminuição de monócitos, neutrófilos, LG-PAS e eosinófilos. Assim, os níveis de B. subtilis avaliados não promoveram crescimento ou alterações fisiológicas nos pirarucus, que indiquem melhoria do seu sistema imune.
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Este estudo avaliou o efeito in vitro do óleo essencial de Mentha piperita L. sobre monogenoideas e sua ação tóxica para Arapaima gigas.
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O objetivo deste trabalho foi determinar a curva glicêmica de juvenis de tambaqui alimentados com dietas contendo 35 e 55% de carboidratos.
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2016