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Ecologia do acará-disco (Symphysodon aequifasciatus, Pelegrin, 1904) (Perciformes: Cichlidae) em igarapés no lago Amanã, Amazonas, Brasil
Get PDFOrnamental fishing has become an important economic activity for Amazonas state, withgreen discus Symphysodon aequifasciatus (Pelegrin, 1904) being one of the most important species in the ornamental fish trade in the state, and also the main species traded in the middle Solimões region. Despite its economic importance, little is known about its biological and ecological characteristics. Autoecology studies the relationships of a single species within its environment, essentially defining the limits of tolerance and preference of the species in face of several ecological factors, examining the action of the environment on its morphology, biology, physiology and behavior. Biological and ecological parameters of the main exploited species are poorly known, nevertheless, these studies are fundamental for a better understanding of relationships between fishes and their natural environments, creating subsidies for sustainable management plans for these species. The present study aimed to investigate aspects of the S. aequifasciatus autoecology at Amana Sustainable Development Reserve, in Amazonas state, Brazil. The following aspects were studied: the species diet, evaluating the items consumed and its temporal variation, the trophic category occupied by the species, its growth rate and longevity. The species reproductive biology was also studied by checking its population
structure, estimating the average size of first maturation, investigating its breeding season and determining its spawning type. Additionally, the S. aequifasciatus genetic populations structure was analyzed within streams associated with Amana Lake, identifying different populations and characterizing potential geographic barriers to gene flow. In addition, a revision of the management norms described in the ornamental fishes Management Plan for the study area was carried out. Genetic analyzes failed to separate (sub) populations of green discus along Amanã Lake, indicating that the study area is a single large panmictic population. Both animal and plant origin items were identified within the species diet, classified as omnivore. The feeding temporal variation observed to the species shows its ability to adapt its diet under changes on food items availability.The species has a long life cycle and intermediate growth rates typical of species with an "equilibrium" life strategy. It
reaches sexual maturity in its first year of life measuring around eleven centimeters long, the maximum longevity recorded was of more than eight years and the males are larger than the females. Spawning occurs at the end of the flooding season and it takes place probably in the flooded forest. The species spawns only once during a single hydrological cycle, when approximately 1000 oocytes are liberated. Characteristics of S. aequifasciatus populations life cycle at Amanã Lake indicate a tendency to classify it as a K-strategist species. Once it is a single population, all streams studied (10) can become potential areas for collection of green discus, nevertheless, a previous survey will be necessary in order to calculate the abundances of the species in each of these igarapés. As captivity does not cause green discus mortality neither changes animals‟ health conditions, it is recommended to choose fish catching and selling period according to commercial issues. Although, a breeding peak was identified between April and June, what makes the months of September and October proper for managed collection period. Observing S. aequifasciatus`s sexual maturation point it is suggested that the minimum catch size for managed fishery at Amanã Lake is 11.50 centimeters. The present study generated important information about S. aequifasciatus ecology which can be very useful to improve the management plan elaborated for the species at the Amanã Sustainable Development Reserve.A pesca ornamental é uma importante atividade econômica para o estado do Amazonas, onde o acará-disco Symphysodon aequifasciatus (Pelegrin, 1904) é uma das espécies mais importantes e representa a principal espécie comercializada na região do médio Solimões. Apesar de sua importância econômica, pouco se sabe sobre seus parâmetros biológicos e ecológicos. A autoecologia estuda as relações de uma espécie com seu meio, definindo essencialmente os limites de tolerância e as preferências da espécie em face dos diversos fatores ecológicos e examinando a ação do meio sobre a morfologia, a biologia, a fisiologia e o comportamento. Esses estudos são fundamentais para um maior entendimento das relações entre os peixes e seus ambientes naturais, gerando subsídios para elaboração de planos de manejo sustentáveis para estas espécies. O presente trabalho teve como objetivo analisar aspectos da ecologia do acará-disco S. aequifasciatus na RDS Amanã (Maraã - AM). Foram estudados: a estrutura genética das (sub) populações de S. aequifasciatus em igarapés tributários do lago Amanã, caracterizando as possíveis barreiras geográficas para o fluxo gênico; a dieta da espécie, avaliando os itens consumidos e sua variação temporal a categoria trófica que a espécie ocupa; a taxa de crescimento e a longevidade da espécie; a estrutura da população; o tamanho médio de primeira maturação gonadal; a época de reprodução; e o tipo de desova. Além disso, foi realizada uma revisão das normas de manejo descritas no Plano de manejo de peixes ornamentais vigente na área de estudo. As análises genéticas não conseguiram separar (sub) populações de acarás-disco ao longo do lago Amanã, indicando que a área de estudo uma única grande população panmítica. A espécie apresenta uma dieta diversificada, consumindo itens de origem vegetal e animal, sendo classificada como onívora. A variação temporal na alimentação demonstra que a espécie consegue adaptar sua dieta à disponibilidade temporal dos itens alimentares. A espécie possui um ciclo de vida longo e taxas de crescimento intermediárias típicas de espécies com estratégia de vida “em equilíbrio”. Atingindo a maturidade sexual no primeiro ano de vida, com cerca de onze centímetros de comprimento, possuindo uma longevidade máxima de mais de oito anos. O machos são maiores que as fêmeas. O período de desova ocorre no final da enchente, com a desova ocorrendo provavelmente no igapó. A espécie desova uma única vez ciclo hidrológico, com uma fecundidade em torno de 1000 oócitos. As populações de S. aequifasciatus do lago Amanã, possuem características de seu ciclo de vida que permitem classificá-la com uma espécie K estrategista. Por se tratar de uma única população todos os 10 igarapés estudados podem virar áreas potenciais de coletas do acará-disco. Porém para que isto ocorra será necessário um levantamento prévio para calcular as abundâncias da espécie em cada um destes igarapés. O tempo de cativeiro não causa mortalidade, ou mesmo altera as condições de saúde dos animais, portanto para os acarás-disco recomenda-se que o melhor momento para a retirada e venda dos peixes esteja vinculada a questões comerciais. Foi identificado um pico de reprodução entre abril e junho, sendo recomendados como período de coleta manejada os meses de setembro e outubro. Os tamanhos mínimos de coleta estão relacionados com o ponto de maturação sexual de cada uma delas. Desta maneira fica sugerido que o tamanho mínimo de captura da pesca maneja de S. aequifasciatus no lago Amanã seja 11,50 centímetros. O presente estudo gerou importantes informações sobre as relaçõesentre o acará-disco e o seu ambiente natural, que servirão para o aprimoramento do plano de manejo elaborado para a espécie na Reserva de Desenvolvimento Sustentável Amanã
Diversidade e variabilidade espaço-temporal da ictiofauna da região estuarina do rio Curuçá município de Curuçá, Pará Brasil
Get PDFThe study of estuarine fish communities has called researchers’ attention due to the fact that these ecosystems present a great variety and abundance of fish, many of which have commercial importance. Such studies have become fundamental in the evaluation of fish stocks, and also contributed to the conservation of coastal and estuarine environments. Rio Curuçá’s estuary is located at the coastline in the northern part of the state of Para, although fishing is the main economic activity in towns of the region, there are a few studies on local ictiofauna. The main objective of this study was to characterize the demersal
ictiofauna of the main channels in the Curuçá River estuary, identifying annual and spatial variations in the composition, density and biomass of ictiofauna, as well as non-biotic factors that influence these variations. In order to this, data collection
trips were carried out once every two months, using trawl net, in two of the main estuary channels. At the end of the study, 18.989 individuals of 73 species were captured. Ophichthus cylindroideus, Hippocampus reidi, Sygnathus pelagicus and
Butis koilomatodon had not yet been registered in the state’s north coastline. Sciaenidae, Engraulidae and Ariidae families were the most representative in number of species, density and biomass. 20 species, classified as estuarine, were majority, and presented leading densities and biomass in all months and capture
stations. Average density (0,12 ind/m²) was significantly greater during the rainy season, but biomass (1,11 g/m²) did not present significant changes during the months of capture. The Curuçá area has presented greater richness of species, density and biomass. This difference is related mainly to a greater heterogeneity of
substrat in the area, and thus a greater availability of microhabitats. Physical and chemical composition of water was homogeneous in capture stations, and had little influence on the spatial distribution of ictiofauna. The registration of new species for the region enforces the importance of other studies for a greater comprehension of local ictiofauna, which is an important economic resource to the local human population.O estudo de comunidades de peixes estuarinos tem recebido a atenção de pesquisadores, pelo fato destes ecossistemas apresentarem uma grande variedade e abundância de peixes. Muitas destas espécies possuem interesse comercial, constituido-se numa ferramenta fundamental para a avaliação dos
estoques pesqueiros, contribuindo também para a conservação dos ambientes estuarinos e costeiros. O estuário do rio Curuçá localiza-se na costa norte, região do salgado paraense, apesar da pesca ser a principal atividade econômica das cidades da região, existem poucos estudos a respeito da ictiofauna local. O objetivo principal deste trabalho foi de caracterizar a ictiofauna demersal dos canais principais do estuário do rio Curuçá, identificando as variações anuais e espaciais na composição, densidade e biomassa, bem como os fatores abióticos que influenciam nestas variações. Para isto, foram realizadas coletas bimestrais, utilizando uma rede de arrasto de fundo, nos dois canais principais do estuário.
Ao final do estudo foram capturados 18.989 indivíduos, pertecentes a 73 espécies, destas Ophichthus cylindroideus, Hippocampus reidi, Sygnathus pelagicus e Butis koilomatodon ainda não haviam sido registradas para a costa norte. As famílias Sciaenidae, Engraulidae e Ariidae, foram as mais representativas em número de espécies, densidade e biomassa, dominando as capturas. As 20 espécies classificadas como estuarinas foram a maioria, e apresentaram as maiores densidades e biomassa em todos os meses e estações de coleta. A densidade média (0,12 ind/m²) foi significativamente maior na estação chuvosa, já para a biomassa (1,11 g/m²) não houve diferenças significativas entre os meses de coleta. Entre os perfis, Curuçá apresentou uma maior riqueza de espécies, densidade e biomassa. Esta diferença está
relacionada principalmente a uma maior heterogenidade de substratos deste perfil, fazendo com que este possua uma maior disponibilidade de microhabitat. Os parâmetros físicos-químicos da água se apresentaram homogêneos ao longo dos pontos de coletas tendo pouca influência sobre a distribuição espacial da ictiofauna. O fato de encontrarmos novos registros de espécies para a região,
reforça a importância de novos estudos para uma maior compreensão da ictiofauna local, que é um importante recurso econômico para as populações locais
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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