Egg transport and larval behavior of curimba, Prochilodus lineatus (Valenciennes, 1836; Characiformes, Prochilodontidae) in a drift simulator channel

Landscape changes and hydrologic alterations associated with dam construction have greatly hindered reproductive success and the recruitment of migratory species. However, little is known about the flow conditions that are necessary for the reproductive success of migrators. We aimed to analyze one of the important migrants of the Paraná River, the curimba, Prochilodus lineatus(Valenciennes, 1836), to determine the minimum velocities necessary for egg drift and analyze the behavior of larvae at different flow velocities. Thus, we experimentally evaluated the behavior of eggs and larvae released in a drift simulator channel (DSC) under four flow velocities. Additionally, we investigate the swimming ability of larvae in relation to certainmorphometric measures of their bodies. We also performed morphometry and calculations of larval body and fin proportions to determine which structures influence swimming ability. The results indicated that environments with flow velocities greater than 0.081 m s-1were favorable for egg drift and increased the chances of successful transportof eggs to downstream areas. We also observed that soon after hatching, the larvae positioned themselves against the flow, indicating that they had a perception of position and orientation. The larvae were able to maintain and disperse against the flow within the channel 32h after hatching at all velocities, which was mainly due to the development of pectoral and caudal fins that were actively involved in the swimming process, as well as the reduction in the dimensions of the yolk sac, which reduced drag.(AU)

Morphometric characteristics and hydrological dynamics in microbasins with different land uses of cerrado soils in Mato Grosso / Características morfométricas e dinâmica hidrológica em microbacias sob diferentes uso do solo do cerrado Mato-Grossense

Understanding the hydrologic regime, and monitoring runoff at the micro-basin scale is critical for understanding water availability, and for managing water resources in strategic biomes such as the cerrado. The objective of this research is to evaluate morphometric characteristics and the hydrologic regime and determine their relationships with soil characteristics and typical land-use in the cerrado biome. To reach this objective morphometric characterization, runoff and precipitation monitoring, and determination of the water retention curve were conducted in three micro-basins in the municipality of Campo Verde, Mato Grosso. These micro-basins each have a different, but regionally typical land use and were selected strategically to represent this area of cerrado: agriculture, pasture and native vegetation. The results obtained allow for the analysis of the hydrologic regime throughout the period measured. Micro-basins with native vegetation and pasture, with greater altimetric range and more sandy soils, show greater erosion. Despite this, the micro-basin with pasture cover showed greater regulation of runoff. The micro-basin with agriculture showed less regularization of water flux due to the physical characteristics of the local soils.

O conhecimento e monitoramento da vazão, assim como o entendimento do regime hidrológico a nível de microbacias tem sido relevante para se determinar a disponibilidade hídrica, assim como promover o gerenciamento dos recursos hídricos em biomas considerados estratégicos como o cerrado. Este trabalho foi desenvolvido com o objetivo de avaliar as características morfométricas e o regime hidrológico e sua relação com as características do solo bem como do seu uso em três microbacias no bioma cerrado. Para alcançar o objetivo proposto, fez-se a caracterização morfométrica, o monitoramento da vazão e da precipitação diária e elaboração da curva de permanência de três microbacias hidrográficas localizadas no município de Campo Verde-MT contemplando os seguintes usos: agricultura, pastagem e vegetação nativa. Essas bacias foram selecionadas estrategicamente por serem representativas dos principais sistemas de uso do solo na região de cerrado. Os resultados obtidos permitem ponderar que há diferença no regime hidrológico das microbacias hidrográficas ao longo do período analisado. As microbacias com vegetação nativa e com pastagem, por terem maior amplitude altimétrica, além de apresentarem solos de textura arenosa, são mais propensas à erosão hídrica. A microbacia com pastagem apresentou maior regularidade na vazão e, a microbacia com agricultura uma menor regularização do fluxo hidrológico em função das características físicas dos solos que compõe a microbacia.

Morphometric characteristics and hydrological dynamics in microbasins with different land uses of cerrado soils in Mato Grosso / Características morfométricas e dinâmica hidrológica em microbacias sob diferentes uso do solo do cerrado Mato-Grossense

Understanding the hydrologic regime, and monitoring runoff at the micro-basin scale is critical for understanding water availability, and for managing water resources in strategic biomes such as the cerrado. The objective of this research is to evaluate morphometric characteristics and the hydrologic regime and determine their relationships with soil characteristics and typical land-use in the cerrado biome. To reach this objective morphometric characterization, runoff and precipitation monitoring, and determination of the water retention curve were conducted in three micro-basins in the municipality of Campo Verde, Mato Grosso. These micro-basins each have a different, but regionally typical land use and were selected strategically to represent this area of cerrado: agriculture, pasture and native vegetation. The results obtained allow for the analysis of the hydrologic regime throughout the period measured. Micro-basins with native vegetation and pasture, with greater altimetric range and more sandy soils, show greater erosion. Despite this, the micro-basin with pasture cover showed greater regulation of runoff. The micro-basin with agriculture showed less regularization of water flux due to the physical characteristics of the local soils.(AU)

O conhecimento e monitoramento da vazão, assim como o entendimento do regime hidrológico a nível de microbacias tem sido relevante para se determinar a disponibilidade hídrica, assim como promover o gerenciamento dos recursos hídricos em biomas considerados estratégicos como o cerrado. Este trabalho foi desenvolvido com o objetivo de avaliar as características morfométricas e o regime hidrológico e sua relação com as características do solo bem como do seu uso em três microbacias no bioma cerrado. Para alcançar o objetivo proposto, fez-se a caracterização morfométrica, o monitoramento da vazão e da precipitação diária e elaboração da curva de permanência de três microbacias hidrográficas localizadas no município de Campo Verde-MT contemplando os seguintes usos: agricultura, pastagem e vegetação nativa. Essas bacias foram selecionadas estrategicamente por serem representativas dos principais sistemas de uso do solo na região de cerrado. Os resultados obtidos permitem ponderar que há diferença no regime hidrológico das microbacias hidrográficas ao longo do período analisado. As microbacias com vegetação nativa e com pastagem, por terem maior amplitude altimétrica, além de apresentarem solos de textura arenosa, são mais propensas à erosão hídrica. A microbacia com pastagem apresentou maior regularidade na vazão e, a microbacia com agricultura uma menor regularização do fluxo hidrológico em função das características físicas dos solos que compõe a microbacia.(AU)

Diet of two insectivorous fish species in a Brazilian semiarid reservoir

Long periods of aridity can cause changes in the diet of fish since hydrological variations affect the availability of food resources. The objective of this study was to investigate the diet of two species of fish (Astyanax aff. bimaculatus and Triportheus signatus), present in the Umari reservoir in Upanema, Rio Grande do Norte, Brazil, to evaluate the influence of seasonality on their diets. The samples were collected quarterly during the months of February to November 2013, with four days in the field, and at five different sites of the reservoir with nets with meshes ranging from 12 to 70 mm (between adjacent nodes). For the identified items in the diet, the frequencies of occurrence and volume, combined in the calculation of the Alimentary Index (IAi), were obtained. Significant alterations in the diet of the species were observed, predominantly in insects. The changes found in the diet indicate an influence of seasonality on the feeding habits of these species, with a predominance of autochthonous items in the dry period and allochthonous items in the rainy period.(AU)

Diet of two insectivorous fish species in a Brazilian semiarid reservoir

Long periods of aridity can cause changes in the diet of fish since hydrological variations affect the availability of food resources. The objective of this study was to investigate the diet of two species of fish (Astyanax aff. bimaculatus and Triportheus signatus), present in the Umari reservoir in Upanema, Rio Grande do Norte, Brazil, to evaluate the influence of seasonality on their diets. The samples were collected quarterly during the months of February to November 2013, with four days in the field, and at five different sites of the reservoir with nets with meshes ranging from 12 to 70 mm (between adjacent nodes). For the identified items in the diet, the frequencies of occurrence and volume, combined in the calculation of the Alimentary Index (IAi), were obtained. Significant alterations in the diet of the species were observed, predominantly in insects. The changes found in the diet indicate an influence of seasonality on the feeding habits of these species, with a predominance of autochthonous items in the dry period and allochthonous items in the rainy period.

Balanço hídrico e excreção renal de metabólitos em ovinos alimentados com palma forrageira (Nopalea cochenillifera Salm Dyck) / Water balance and renal excretion of metabolites in sheep fed forage cactus (Nopalea cochenillifera Salm Dyck)

Objetivou-se avaliar balanço hídrico e excreção renal de metabólitos em borregos sem raça definida, alimentados com diferentes quantidades de palma forrageira (Nopalea cochenillifera Salm Dyck), na forma in natura e em farelo. Foram utilizados 20 borregos, com peso vivo médio inicial de 20 Kg e foram distribuídos no delineamento inteiramente casualizado, sendo cinco tratamentos e quatro repetições. As dietas experimentais consistiram em uma dieta controle à base de feno de tífton, farelo de soja, suplemento mineral e calcário, os demais tratamentos visaram testar níveis diferentes de palma forrageira corrigida com ureia em duas formas: in natura e farelada e em dois níveis de substituição (50 e 100%) da matéria seca do feno de tífton. Amostras de sangue e urina foram coletadas para determinação de diferentes metabólitos e minerais e utilização de equações para obtenção dos índices de excreção urinária destes metabólitos, taxa de depuração endógena de creatinina e reabsorção de água livre de eletrólitos, além do registro de ingestão de água e volume de urina. A ingestão voluntária de água sofreu influência das dietas, sendo que os animais submetidos às dietas contendo farelo de palma e feno e farelo de palma foram superiores aos demais tratamentos. A ingestão de água via alimentos também sofreu influência da dieta, sendo maior nos animais que receberam palma in natura e farelo mais palma in natura. Com relação à ingestão total de água foi maior para os animais alimentados com dietas contendo palma in natura em relação aos demais tratamentos. As dietas experimentais influenciaram na excreção renal de metabólitos derivados purínicos e minerais, sem alterar a função renal. A presença da palma forrageira tanto na condição de farelo como in natura proporciona aumento do volume urinário sem alterar a função renal, além de que deve ser considerado como uma excelente estratégia alimentar no semiárido.(AU)

This study aimed to assess fluid balance and renal excretion of metabolites in lambs without defined breed standard, fed different forage cactus (Nopalea cochenillifera Salm Dyck), in natura and bran. 20 lambs were used, with initial body weight of 20 kg and were distributed in a completely randomized design, with five treatments and four repetitions. The experimental diets consisted of a control diet based on Bermuda grass hay, soybean meal, limestone and mineral supplement, other treatments aimed at testing different levels of cactus pear plus urea in two forms: fresh and mash and two levels of substitution (50 and 100%) of dry matter of hay. Blood and urine samples were collected for determination of different metabolites and minerals and use of equations to determine the rates of urinary excretion of these metabolites, rate of endogenous creatinine clearance and electrolyte reabsorption of free water, in addition to recording of water intake and urine volume. The voluntary water intake was influenced by the diets, and the animals subjected to diets containing soybean meal and hay palm and cactus meal were higher than other treatments. Water intake via food was also influenced by diet, being higher in animals fed palm fresh and bran over palm in nature. With respect to total water intake was greater for cows fed diets containing palm in nature compared to the other treatments. The experimental diets influenced the renal excretion of purine metabolites and minerals derived, without changing renal function. The presence of cactus pear both as bran as in nature provides increased urine volume without changing renal function, and to be considered as an excellent food strategy in semiarid.(AU)

Relationship between hydrology and aquatic ecosystems in the Araguaia river floodplain - DOI: 10.4025/actascibiolsci.v30i4.5866 / Relações entre o regime hidrológico e os ecossistemas aquáticos da planície aluvial do rio Araguaia - DOI: 10.4025/actascibiolsci.v30i4.5866

The Araguaia river is the most important fluvial system draining the Cerrado biome of Brazil. Results are presented here on the hydro-geomorphologic behavior of this fluvial system and its effect on the floodplain ecosystems. Discharge from nine gauge stations in the upper, middle and lower course of the Araguaia River, from 1970 to 2004, were analyzed. The hydrological regime depends strongly on the tropical wet-dry climate, with floods from January to May and low water between June and September. In the upper and lower courses, there is a high variation between maximum and minimum peaks because the underdevelopment of the floodplain, while in the medium course the flow peaks are smoothed by the presence of a well-developed river floodplain. In this area, the river can lose up to 30% in water discharge, which is stored in the floodplain. Three types of flood categories were defined, and two mechanisms of flow storage and transfer were identified, explaining the discharge loss in the middle course. Three main mechanisms produce the water loss mid-course: the sponge effect of the alluvial plain, the existence of a well-developed mosaic of lakes, and an arboreal-dominated vegetation stratum of alluvial forest.

O rio Araguaia se constitui no principal sistema fluvial que percorre o Brasil central. Neste artigo, são apresentadas algumas observações sobre o seu comportamento hidrogeomorfológico e suas aplicações no estudo de ecossistemas aquáticos. Os resultados foram gerados pelo processamento de dados de vazão de uma série histórica de 35 anos de registro (1970 a 2004), em nove estações hidrológicas, envolvendo o alto, médio e baixo curso. A distribuição de vazões no curso médio resulta atípica nas cheias extremas, pois o rio perde até 30% de sua vazão. No total, foram definidos três tipos de enchentes e dois mecanismos particulares de armazenamento e transferência de fluxos, que explicam as perdas de fluxos no médio curso. Três são os principais fatores condicionantes da perda de vazão: a) a existência de uma planície aluvial bem desenvolvida, b) a existência de um complexo de sistema de lagos na planície aluvial, c) a vegetação dominantemente arbórea, que freia a onda de cheia e contribui para o armazenamento de água na planície aluvial

Determinação de idade e crescimento do mapará (Hypophthalmus marginatus) na Amazônia Central

The present work seeks to contribute for the conservation and management of the mapará(Hypophthalmus marginatus), an important export fishing resource of Amazonas for which is necessary to know essential information of its population dynamics. To contribute to this purpose, the present work established as objective to identify a structure for reading of age rings, to determine the parameters of growth of the mapará (H. marginatus), Central Amazon, Amazonas - Brazil. The work was made through the otoliths analysis collected in the period of December of 1996 to August of 1997. The otolith chosen for reading was the asteriscus, being the reading made in a stereomicroscope with coupled monitor. The mark structures were validated by means of the analysis of the relative marginal increment, being found two rings. The values estimated for the parameters in the period were L FONT FACE=Symbol>¥ /FONT> = 52,63 cm; k = 0,555 year; to = -0,029 and M = 0,552. The hydrologic cycle and reproductive behavior were the responsible factors for age rings.

O presente trabalho visa contribuir para a conservação e manejo do mapará (Hypophthalmus marginatus), um importante recurso pesqueiro de exportação do Amazonas para o qual é necessário conhecer informações essenciais de sua dinâmica de populações. Para contribuir à esta finalidade, o presente trabalho estabeleceu como objetivo identificar o par de otólito mais adequado para leitura de anéis etários, determinar os parâmetros de crescimento do mapará (H. marginatus), Amazônia Central, Amazonas - Brasil. O trabalho foi efetuado através da análise de otólitos coletados no período de dezembro de 1996 á agosto de 1997. Os otólitos escolhidos foram os asteriscus, sendo a leitura efetuada em lupa estereoscópica com monitor acoplado. As marcas de crescimento foram validadas por meio da análise do incremento marginal relativo, sendo encontrado dois anéis/ano. Os valores estimados para os parâmetros no período foram L FONT FACE=Symbol>¥ /FONT> = 52,63 cm; k = 0,555 ano; to = -0,029 e M = 0,552. O ciclo hidrológico e comportamento reprodutivo estão relacionados com a marcação de anéis etários.

Relationship between hydrology and aquatic ecosystems in the Araguaia river floodplain - DOI: 10.4025/actascibiolsci.v30i4.5866 / Relações entre o regime hidrológico e os ecossistemas aquáticos da planície aluvial do rio Araguaia - DOI: 10.4025/actascibiolsci.v30i4.5866

The Araguaia river is the most important fluvial system draining the Cerrado biome of Brazil. Results are presented here on the hydro-geomorphologic behavior of this fluvial system and its effect on the floodplain ecosystems. Discharge from nine gauge stations in the upper, middle and lower course of the Araguaia River, from 1970 to 2004, were analyzed. The hydrological regime depends strongly on the tropical wet-dry climate, with floods from January to May and low water between June and September. In the upper and lower courses, there is a high variation between maximum and minimum peaks because the underdevelopment of the floodplain, while in the medium course the flow peaks are smoothed by the presence of a well-developed river floodplain. In this area, the river can lose up to 30% in water discharge, which is stored in the floodplain. Three types of flood categories were defined, and two mechanisms of flow storage and transfer were identified, explaining the discharge loss in the middle course. Three main mechanisms produce the water loss mid-course: the sponge effect of the alluvial plain, the existence of a well-developed mosaic of lakes, and an arboreal-dominated vegetation stratum of alluvial forest.

O rio Araguaia se constitui no principal sistema fluvial que percorre o Brasil central. Neste artigo, são apresentadas algumas observações sobre o seu comportamento hidrogeomorfológico e suas aplicações no estudo de ecossistemas aquáticos. Os resultados foram gerados pelo processamento de dados de vazão de uma série histórica de 35 anos de registro (1970 a 2004), em nove estações hidrológicas, envolvendo o alto, médio e baixo curso. A distribuição de vazões no curso médio resulta atípica nas cheias extremas, pois o rio perde até 30% de sua vazão. No total, foram definidos três tipos de enchentes e dois mecanismos particulares de armazenamento e transferência de fluxos, que explicam as perdas de fluxos no médio curso. Três são os principais fatores condicionantes da perda de vazão: a) a existência de uma planície aluvial bem desenvolvida, b) a existência de um complexo de sistema de lagos na planície aluvial, c) a vegetação dominantemente arbórea, que freia a onda de cheia e contribui para o armazenamento de água na planície aluvial