132 research outputs found
RELAÇÕES PESO-COMPRIMENTO E COMPRIMENTO-COMPRIMENTO PARA 37 ESPÉCIES DE PEIXES DEMERSAIS DO CANAL PRINCIPAL DO RIO MARAPANIM, COSTA NORDESTE DO ESTADO DO PARÁ, BRASIL
Length-length and weight-length relationships are presented for 37 demersal fish species caught in the main channel of the Marapanim River. The mean allometric coefficient (b) in the weight-length relationship (W = aLb) was 3.04 (±0.32). Positive allometry was predominant (15 species, 42.1%), followed by isometry (13 species, 34.2%), and negative allometry (9 species, 23.7%). The present study represents the first reference of length-length relationships for the northern coast of Brazil. Keywords: Demersal fishes; allometric coefficient; Marapanim; northern coast of Brazil.Relações comprimento-comprimento e peso-comprimento são apresentadas para 37 espécies de peixes demersais capturadas no canal principal do rio Marapanim. O coeficiente alométrico (b) da relação peso-comprimento (W = aLb) apresentou média de 3,04 (±0,32). A alometria positiva foi dominante (15 espécies, 42,1%), seguida por isometria (13 espécies, 34,2%) e alometria negativa (9 espécies, 23,7%). O presente estudo representa a primeira referência de relação comprimento-comprimento para costa norte do Brasil.Palavras-chave: Peixes demersais; Coeficiente alométrico; Marapanim; Costa norte do Brasil
ESTIMATES OF ANNUAL FOOD CONSUMPTION/BIOMASS RATIO (Q/B) FROM THE FISH FAUNA OF A MANGROVE ESTUARY IN NORTH BRAZIL
Para contribuir para a construção de um modelo de balanço trófico, as estimativas das relações de consumo de alimentos por unidade de biomassa (Q/B) foram compiladas para 37 espécies de peixes do estuário do Curuçá selecionados no Norte do Brasil usando um modelo empírico. As amostras foram coletadas bimestralmente entre Julho de 2003 e Julho de 2004 no canal principal e áreas intertidais usando uma rede de arrasto modelo “otter trawl” e uma rede “fyke”, respectivamente. O aspect ratio da nadadeira caudal variou entre 0,8 para Poecilia vivipara e 4,6 para Sciades herzbergii e o Q/B variou de 2,3 para Epinephelus itajara para 67,3 para Cetengraulis edentulus. Este estudo representa a primeira referência disponível dos valores de Q/B para 29 espécies de peixes. Esta compilação de Q/B deveria ser utilizada para a construção de modelos de Ecopath específicos para condições tropicais.Palavras-chaves: consumo/biomassa; aspect ratio; modelo trófico; ictiofauna; Ecopath.To contribute to mass balanced trophic model parametrization, estimates of annual food consumption/biomass ratio (Q/B) were compiled for 37 selected fish species of the Curuçá Estuary in Northern Brazil using an empirical model. Samples were taken bimonthly between July 2003 and July 2004 in the main channel and intertidal creeks using an otter trawl and a fyke net, respectively. The aspect ratio of the caudal fin varied between 0.8 for Poecilia vivipara and 4.6 for Sciades herzbergii and the Q/B ranged from 2.3 for Epinephelus itajara to 67.3 for Cetengraulis edentulus. This study represents the first reference available on Q/B values of 29 fish species. This compilation of Q/B ratio presented here should be useful for construction of Ecopath models particularly in tropical conditions.Keywords: consumption/biomass; aspect ratio; trophic models; Ecopath
Jean-Louis BAUDOUIN et Yvon RENAUD, Code civil annoté, Montréal, Wilson et Lafleur Ltée, 1988-89, 3 vol., vol. 1: 776 p., vol. 2: 750 p., vol. 3: 584 p., ISBN 2-89127-090-8, 2-89127-089-4, 2-89127-088-6.
The assumption for this study was that litterfall in floodplain environments of the middle Xingu river follows a pattern of seasonal variation. According to this view, litterfall production (total and fractions) was estimated in four alluvial rainforest sites on the middle Xingu River over an annual cycle, and examined the effect of seasonal flooding cycle. The sites included two marginal flooded forests of insular lakes (Ilha Grande and Pimentel) and two flooded forests on the banks of the Xingu itself (Boa Esperança and Arroz Cru). Total litterfall correlated with rainfall and river levels, but whereas the leaf and fruit fractions followed this general pattern, the flower fraction presented an inverse pattern, peaking in the dry season. The litterfall patterns recorded in the present study were consistent with those recorded at other Amazonian sites, and in some other tropical ecosystems.O pressuposto para este estudo foi que a produção de serrapilheira nos ambientes inundáveis do médio rio Xingu, segue um padrão de variação sazonal. Assim, se quantificou durante um ciclo anual a produção de serapilheira total e de suas frações, e se indagou a correlação entre o regime do nível do rio e a produção de serapilheira. Quatro ambientes de floresta ombrófila aluvial foram estudados: duas florestas inundáveis de lagoas insulares (Ilha Grande e Pimentel) e dois ambientes de floresta marginal no canal principal do rio Xingu (Boa Esperança e Arroz Cru). A produção de serapilheira total nos quatro ambientes mostrou um padrão sincrônico com a variação do nível do rio e com a inundação das áreas marginais. Por sua vez, foi evidente um aumento da produção de frutos durante a inundação local e de forma inversa uma maior produção de flores com o regime de seca. Os padrões registrados para os componentes de serapilheira do médio rio Xingu, confirmam os achados para outros ambientes amazônicos e tropicais
RELAÇÕES COMPRIMENTO-COMPRIMENTO E COMPRIMENTO-PESO PARA A ICTIOFAUNA DAS CABECEIRAS DA SERRA ONÇA PUMA, REGIÃO AMAZÔNICA, BRASIL
Length–length (LLR) and length–weight (LWR) relationships are presented for 19 fish species collected between 2009 and2011 insmall tributaries and headwaters areas of the Tocantins-Araguaia basin, Itacaiúnas drainage, Southwestern Pará, Amazonian, Brazil. This study describes the first reference of LLR for 13 species and LWR for 16 fish species.Keywords: Allometry, Itacaiúnas, ichthyofauna.Relações Comprimento-Comprimento (RCC) e Comprimento-Peso (RCP) são apresentadas para 19 espécies de peixes coletadas entre 2009 e 2011 em pequenos tributários de cabeceira da bacia do Toncantins-Araguaia, drenagens do Itacaiúnas, Sudoeste do Estado do Pará, Região Amazônica, Brasil. Este estudo relata a primeira referência de RCC para 13 espécies e de RCP para 16 espécies de peixes.Palavras-chave: Alometria, Itacaiúnas, ictiofauna
Control knowledge in physics. Tests. Grade 11
Запропоновані тестові завдання можуть бути використані як для поточної перевірки знань учнів, так і для тематичних та семестрових атестацій.Предложенные тестовые задания могут быть использованы как для текущей проверки знаний учащихся, так и для тематических и семестровых аттестаций.The proposed tests can be used to test knowledge of current students, and for thematic semester and certification
PRIMEIRO REGISTRO DE Cymothoa sp. FABRICIUS, 1793 (ISOPODA: CYMOTHOIDAE) PARASITANDO O PEIXE DE QUATRO OLHOS, Anableps anableps (CYPRINODONTIFORMES: ANABLEPIDAE), NA COSTA NORTE BRASILEIRA
This study presents the first record of the occurrence of Cymothoa Fabricius, 1793 in northern Brazil, as well as in four-eyed fish Anableps anableps. The research was conducted in the Curuçá estuary, in northern Brazil, where 158 specimens of A. anableps were collected, with nine Cymothoa specimens being found on nine different fish. These isopods were identified by sequencing the mitochondrial Cytochrome Oxidase I gene. The prevalence of the parasite (4.43 %) in A. anableps was extremely low and Cymothoa sp. specimens were found primarily in the gills of the host fish.Keywords: Amazon; Isopoda; Crustaceans; Four-Eyed Fish; Anablepidae.Este estudo apresenta o primeiro registro da ocorrência de Cymothoa Fabricius, 1793 no norte do Brasil, bem como no peixe de quatro olhos Anableps anableps. A pesquisa foi realizada no estuário de Curuçá, no norte do Brasil, onde foram coletados 158 espécimes de A. anableps, com nove espécimes de Cymothoa, sendo encontrados em nove peixes diferentes. Esses isópodes foram identificados pelo sequenciamento do gene mitocondrial do citocromo oxidase I. A prevalência do parasita (4.43 %) em A. anableps foi extremamente baixa e os espécimes de Cymothoa foram encontrados principalmente nas brânquias do peixe hospedeiro.Palavras-chave: Amazônia, Isopoda, Crustáceos, Peixe com quatro olhos, Anablepidae
LENGTH-WEIGHT RELATIONSHIPS FOR FISH FAUNA FROM WATERBODIES IN THE UPPER TAPAJÓS RIVER BASIN OF PALITO MOUNTAIN RIDGE, BRAZILIAN AMAZON REGION
Relações comprimento-peso (RCP) de 14 espécies de peixes da Serra do Palito, alto Rio Tapajós, região amazônica brasileira foram estimadas. Este estudo apresenta a primeira RCP para o pequeno characídeo Hemigrammus marginatus, e fornece adicionalmente novos registros máximos de comprimento e peso para quatro e três espécies, respectivamente.Palavras-chave: Peixes de água doce neotropicais, relação peso-comprimento, bacia do rio Tapajós, alometria.Length-weight relationships (LWR) of 14 fish species were estimated from Palito Mountain ridge, upper Tapajós river basin, Brazilian Amazon region. This study represents the first LWR to the small characid Hemigrammus marginatus, and additionally provides new maximum record of length and weight for four and three species, respectively.Keywords: Neotropical freshwater fish fauna; Length-weight relationship; Tapajós river basin; Allometr
Redescription and geographical distribution of the endangered fish ossubtus xinguense Jégu 1992 (Characiformes, Serrasalmidae) with comments on conservation of the rheophilic fauna of the Xingu River
The monotypic species Ossubtus xinguense was originally described based on scarce material putatively divided into juveniles and adults. Ossubtus xinguense has a restricted distribution and was previously known only from a few rapids downstream of the city of Altamira, in the Volta Grande stretch of the Middle Xingu River. Until recently, the species was rare in museums because its habitat (large rapids) is difficult to sample. Large-scale collecting efforts targeting rapids throughout the Xingu River basin have yielded an abundance of new material. Based on an analysis of the type series and freshly preserved specimens, we redescribe O. xinguense and provide detailed osteological descriptions along with comments about its relationships within Serrasalmidae. Furthermore, we expand the geographical distribution of the species and discuss its conservation status. © 2016 Andrade et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Temporal patterns in the occurrence of selected tropical fishes in mangrove creeks: implications for the fisheries management in north Brazil
Intertidal Biogeographic Subprovinces: Local and Regional Factors Shaping Fish Assemblages
Intertidal zones shelter a wealth of species and natural resources, provide important ecological services, and sustain several economic activities in coastal communities. However, the tidepool fish species that inhabit the intertidal zone are subject to a wide array of impacts due to the human presence and their accessibility, creating a challenge for the mitigation of habitat loss, in particular in tropical regions where the ecology and distribution of species are poorly known. In this study, we investigated tidepool fish species distribution patterns systematically across ca. 4,900 km of tropical Brazilian coastline (00–21° latitude) in order to verify the latitudinal trends and environmental variables influencing tidepool communities. A total of 5,113 fish specimens belonging to 67 taxa were collected at the 19 sites, revealing four distinct biogeographic subprovinces: Amazon Estuary (AE), Northern Mangrove (NM), Northeastern Semiarid (NS), and Tropical Warm (TW). Distance-based linear modeling evidenced in sequence water salinity, tidal range, shape of rocky shore formation, algae cover, distance to subtidal zone, latitude and rainfall as the most important environmental variables to shape biogeographic subprovinces. Fish species such as Bathygobius soporator, Bathygobiusgeminatus, Labrisomus nuchipinnis, and Scartella cristata presented wide distribution, occupying more than one subprovince. The trophic structure of the tidepool fishes also varied among subprovinces, with carnivores being associated with the AE subprovince, omnivores with the NM, and herbivores dominating the NS and TW. These findings reinforce the determining role of local and regional factors in the geographic distribution of fish and, in particular, highlight a new arrangement for the intertidal subprovinces of the tropical Brazilian shoreline, which may provide a valuable tool for the more effective management and conservation of this vulnerable ecosystem at the land-ocean interface
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