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

Early ontogenetic development of Cynodon gibbus (Characiformes: Cynodontidae) in the Amazon River basin

Abstract Knowledge regarding the early life history of neotropical fish, although incipient, is crucial for the accurate identification of larvae collected from the natural environment. Such details are important for defining spawning, drift, and nursery areas as well as the reproductive periods of species. Herein, the larval development of Cynodon gibbus was described using morphological, meristic, and morphometric characteristics. Specimens were collected from open water limnetic zones and under macrophyte stands in the Amazon basin from 2010 to 2023. Forty-eight larvae with standard lengths ranging from 5.73 to 21.57 mm were studied. The larvae have a long to very long body, small eyes, and a small head, which progresses to a moderate size in the preflexion stage. Furthermore, the larvae had ample mouths with numerous conical teeth, an oval-triangular swim bladder, overlapping dorsal and anal fins, and the tip of the pectoral fin not reaching the swim bladder. Pigmentation pattern comprised two punctate pigments above the fontanelle, the rectum, and at the lower and upper ends of the caudal peduncle. Various body parts exhibited predominant allometric relationships, reflecting differential developmental rates among them in response to fundamental ecological requirements for survival. The C. gibbus larvae can be identified by a combination of the position of dorsal, anal and pectoral fins, pigmentation pattern, swim bladder shape, and the total number of myomeres (51 to 53)